Some beginner questions on split units.

[Reptile]

Hi all

I have just put in my first MHI split unit, which went well overall, but I have a few questions which I'm not going to find in the documentation, so thought I'd keep them all together in one place. Apologies if they are a bit random or daft.

1) In the evacuation process I had my digital gauge inline inbetween the manifold low-side and service valve, and the pump in to the centre port of the manifold. I had to see positive pressure when releasing the gas before I could remove my gauge, and lost some gas in the meantime. What is the best configuration and process to use when evacuating? (idiots guide). Should I have my gauge tapped into my manifold instead just using one port on it (ie not 'inline')?

2) Related to the above... I was seeing 300 microns with the pump running, but isolate the pump and that quickly rose (within 1 minute) to 1000 where it settled and didn't rise. I evacuated for another 3 hours and this was still the same, so figured it was fine, as it was a lengthy pipe run. I was careful to keep the caps on the pipes when installing and it pressure tested fine. Is this normal behaviour, or have I been too hasty in releasing the gas?

3) I know it will change according to many factors, but roughly what pressure should I be seeing on my manifold low-side when all the gas is released into the system? Just as a peace-of-mind check.

4) I couldn't find imperial sized insulation. For 1/4" (6.35mm) and 3/8" (9.52mm) copper I ordered 6mm and 10mm armaflex. The 6mm fits great, but the 10mm is pretty loose on the pipe. A bit concerned it will not be effective !?

5) Insulation again - how far up into the indoor unit do you insulate with armaflex? My indoor unit came with both pipes held loosely together in some sort of foam. I installed it as-was and then stripped what I could off the pipework that was external, and replaced with armaflex up to the hole in the wall, but the internal pipe is still just loose in the original stuff.

6) Last one - I did have to re-do the flare a few times to get it to seal. Eventually I just nipped it up a bit extra on the torque wrench, and this worked. Especially on the 1/4". I have the proper eccentric 410a tool and oiled the outside of the flare, but when the tool completes a flare it leaves 'ridges' in the copper at 180 and 360 degrees, where it snaps off when it is done. Could this be causing a problem? Or do you generally just need an extra turn on the wrench (18 & 42 nm I think it was).

Cheers

Reptile

[fridge doctor]

Trying hard not to be rude... Have you actually had any training?

1/ Common sense
2/ 3 hours is ridiculous
3/ Don't concern yourself
4/ It's fine
5/ It's fine
6/ " I did have to re-do the flare a few times to get it to seal" This is not good, nor are the 'ridges' you are doing something very wrong. I re-iterate have you had any training?

[monkey spanners]

Hi Reptile,

A lot of this would have been covered in your F gas training, assuming you have passed it, if you have not you are working illegally.

Changing the oil in the vac pump can often bring about a better vacuum. Once the oil is saturated with moisture no amount of vac time will reduce the vacuum in the system. An indicator is the level of vacuum the pump will pull just connected to the vac gauge, should be something like 50 microns or so but check the handbook for your specific pump.

The pressure in the system once the refrigerant is released is determined by the temperature of the pipe work and system, look it up on a pressure temperature chart, the pressure will be constant at a constant temperature so long as there is enough refrigerant for a drop of liquid to form right up until the system is nearly full up! pressure tells you very little really. (again this would have been in you F gas test...)

The ridges on the flare are likely due to the two halves of the flaring block not having been aligned properly before the were clamped together.

Take care, this stuff is dangerous, and sometimes fatal, i know a few seasoned techs who have had near misses,

Jon

[Contactor]

1. You can have your gauge anywhere that is open to the vacuum, there is no 'correct method' - you may find some ways are more practical though. Ideally you should have the gauge at the furthest point from the pump, particularly on bigger jobs. Some lines have in line valves and you could also try using quick couplers to prevent loss of gas. There is a wrong and right way to remove gauges but some systems (most splits) only have a low side access fitting.

2 For the depth of vacuum measure the ambient temperature at the coldest point in the system and refer to a steam chart for your given ambient to calculate the depth of vacuum. Generally speaking, the warmer the ambient the shorter time it will take (relative to system size). Obviously if the temperature is below 0c you will not be able to achieve sufficient vacuum at all.

3 Your gas will be sitting as a two phase mixture at saturation point. Therefore you will need to know what gas you are using and refer to a pt chart to determine the pressure, this can be a useful tool if you turn up to site and the units are not labelled.

4 The internal bore of insulation varies between manufacturers even in imperial sizes so dont worry about being too exact.

5 All exposed copper should be insulated, they sometimes supply the units with both pipes pre insulated a short distance, you can leave it on.

6 The face of your flare should be smooth, either your tool has had it or you are not forming the flare properly, it's easy to make the flare too big for example

It all comes with a bit of experience, sometimes being thrown in at the deep end is a great way to learn.

[nike123]

1) In the evacuation process I had my digital gauge inline inbetween the manifold low-side and service valve, and the pump in to the centre port of the manifold. I had to see positive pressure when releasing the gas before I could remove my gauge, and lost some gas in the meantime. What is the best configuration and process to use when evacuating? (idiots guide). Should I have my gauge tapped into my manifold instead just using one port on it (ie not 'inline')?

http://www.mediafire.com/?zmyztx5gnzm

It could be tapped. But, when evacuating, ordinary hoses (and manifold gauges) are not good, because they are not designed to maintain negative pressure.
You need specially designed manifolds and hoses to make and hold good vacuum.

http://www.appioninc.com/products/hosefeatures.html
http://www.appioninc.com/products/mgamanfeatures.html
http://www.appioninc.com/downloads/f...t_Brochure.pdf

Therefore your problem below:

2) Related to the above... I was seeing 300 microns with the pump running, but isolate the pump and that quickly rose (within 1 minute) to 1000 where it settled and didn't rise. I evacuated for another 3 hours and this was still the same, so figured it was fine, as it was a lengthy pipe run. I was careful to keep the caps on the pipes when installing and it pressure tested fine. Is this normal behaviour, or have I been too hasty in releasing the gas?

6)

Last one - I did have to re-do the flare a few times to get it to seal. Eventually I just nipped it up a bit extra on the torque wrench, and this worked. Especially on the 1/4". I have the proper eccentric 410a tool and oiled the outside of the flare, but when the tool completes a flare it leaves 'ridges' in the copper at 180 and 360 degrees, where it snaps off when it is done. Could this be causing a problem? Or do you generally just need an extra turn on the wrench (18 & 42 nm I think it was).

After cutting pipe you should remove burr with special tool:


Than you could proceed with flaring after you oiled flaring tool forming surface

Your flared pipe end should be withot any scrach, perfectly flat and even.
Buy Imperial "Roll-AIR"
http://www.imperial-tools.com/tools/...gtools_02.html

or Ridgid ratchet flaring tool
http://www.ridgid.com/Tools/458R-Rat...l/EN/index.htm

[Reptile]

Thanks Nike. My flaring tool is almost exactly like that Ridgid one. My ridges are on the outside of the flare. I have identified the problem - my tool is out of line. You can tell my running your fingernail over the loop, and it catches on the rim. Obviously the inside of the flare is smooth and fine to the eye, but must be slightly distorted if the outer edge is distorted.

I have 2 types of de-burrer. The sort you posted, at the end of my cutting tool, and a cone type. I find that if I use the one you posted, I mark the inside of the pipes, so I've been using the other. Might invest in a proper one like you posted - and a new flarer

[Reptile]

Trying hard not to be rude... Have you actually had any training?

1/ Common sense
2/ 3 hours is ridiculous
3/ Don't concern yourself
4/ It's fine
5/ It's fine
6/ " I did have to re-do the flare a few times to get it to seal" This is not good, nor are the 'ridges' you are doing something very wrong. I re-iterate have you had any training?

No offence, but you failed.

Clearly No, I have not had any training, I am a DIY'er. I have read enough threads on this forum to know what the general opinion is of DIY'ers, so i don't need you to repeat them. I think the reasons people like me are starting to DIY are pretty obvious, and I was in a unique position that I could get all the necessary equipment. If you feel that replying causes you legal or moral issues, then I respect that.

1) In light of the above, I disagree.
2) I've read of people doing it for longer on here!
3) Why not? it seems reasonable to me to know a figure so i can attach my manifold gauges and satisfy myself I haven't had a leak.
4) OK. But again not the most helpful reply I've ever read. I have been reading posts about leaks caused by condensation, and other posts saying insulation must be on tight, and covering all joints etc. So not too unreasonable a question I didn't think.
5) As above
6) I've just clarified this, but my tool appears to be at fault, if it isn't normal.

Regards

Reptile.

[monkey spanners]

I didn't even get told i was rude

[Reptile]

Monkeyspanners, I must apologise, having re-read your post, somehow I have missed your explanation on the 2 halves of the flaring tool being misaligned. Must have skimmed it. As it goes, you were bang right. And your post was informative and not rude, even thought you didn't miss the opportunity to mount the high-horse about the F Gas just slightly.

So is it common then? The ridges on the flare? I'm guessing to some extent they get squished down by the flare nut. Or is it a no-no?

Slightly annoyed my expensive tool came like this, AND I've installed one unit with it, blowing a fair amount of Nitrogen in the process.

[Brian_UK]

<snip>even though you didn't miss the opportunity to mount the high-horse about the F Gas just slightly.<snip>

You might consider it high-horse but when we have invested a fair amount of time and money to enable us to work legally within the law of the land we do a get little peeved when others, such as yourself, are able to simple ignore it without penalty.

It is the same with the Gas Industry so you are not unique in this matter.

[monkey spanners]

My expensive ITE flairing tool did the same thing last week, i haven't used it for a month or so as i braze everything in now if possible, i put it down to operator error on my part.
The tool has a hinge at one end and a taper pin to align the two blocks at the other, the next time i used it i paid more attention to the block alignment before i clamped the two halves with the windy cone doodad.

You get a free high horse when you finish your F gas course, its costing me a fortune in hay at the moment what with the poor summer we have had...

On a more serious note i don't really have a problem with people doing stuff themselves, i work on my car and lorry yet am not a motor technician, but something you may not be aware of is that we as an industry have had to spend ££££ on training ££ on registration £££ on waste transfer licences and personally have just spent £££ on some digital gauges to help us comply with the new law, the one saying you shouldn't be doing what you are doing, only for the government to not enforce it and the general public to carry on as before, so sometimes while we're sat here at home trying to help some one get something working and not injure themselves or heaven forbid release refrigerant into the atmosphere we might just be slightly flipant or even rude

I suppose a motoring equvalent would be that you are an uninsured driver with no mot speeding down the road, and we are paying the extra premiums and having to suffer speed cameras.

Jon

[Reptile]

You might consider it high-horse but when we have invested a fair amount of time and money to enable us to work legally within the law of the land we do a get little peeved when others, such as yourself, are able to simple ignore it without penalty.

It is the same with the Gas Industry so you are not unique in this matter.

Thanks for your input Brian.

I must admit, I don't know the ins and outs of the law, but I fail to see how Joe Bloggs installing a DIY special from B&Q is any better than me, who has spent months reading about the correct procedures and buying the right gear, installing a pre-charged split. I am not 'dealing' with the refrigerant. I am releasing it. At my current level of knowledge, if I moved house, I'd probably get someone in to do it. As I would if my system developed a leak and needed re-charging. But I might keep learning

I believe it is an easy smoke-screen to hide behind, this 'law' thing. I have to wonder if what is really going on, is anger that the air-con industry is becoming accessible to the DIY'er. I have seen the thread about "DIY sales are killing our industry". I have also seen a post by yourself, if memory serves - but I could well be wrong, saying that you wouldn't commision an AC unit if someone had installed the equipment themselves. Why? This is slightly galling to someone like me, who hasn't sat the course, but is MORE than capable of coring a hole in my wall, screwing some trunking to the wall, and bending some pipe. Why should I pay someone to do that? In fact I'd go a step further, and say the planning and care I've taken on my OWN property, is more than a 'professional' would have.

Which brings me to another post, where someone was telling a story of a 'professional', their colleague no less, that installed a system without pressure testing and messed up the evacuation. Why should i risk that?

Last week my car went in for its MOT, and failed. I did the work myself, saving myself a bundle. The garage retested it for me, it passed. I fail to see any major differences here. Those mechanics have also invested time and money sitting courses and training.

I've spent 7 years training myself in my profession, but I still post advice on forums for others who are willing to try, and don't whinge at shops employing monkeys who don't know what they are doing.

I use a lot of forums, a really wide range, and I've never come across any so generically inverted as this one. It is a great site - wealth of information, but you all seem to believe that you have the right to reserve this work for yourselves. I would have happily paid someone a reasonable amount to come an commission my gear. I am probably the 1% that have the urge to do it myself, so whats the harm? I wonder if you are ultimately hurting yourselves. I've already seen a few posts by some people who are snapping up comissioning work, I think it was "Those who do, do, those who don't whinge on forums". Well in times like these I hope those that don't do OK.

[frank]

Hi all

I have just put in my first MHI split unit, which went well overall, but I have a few questions which I'm not going to find in the documentation, so thought I'd keep them all together in one place. Apologies if they are a bit random or daft.

1) In the evacuation process I had my digital gauge inline inbetween the manifold low-side and service valve, and the pump in to the centre port of the manifold. I had to see positive pressure when releasing the gas before I could remove my gauge, and lost some gas in the meantime. What is the best configuration and process to use when evacuating? (idiots guide). Should I have my gauge tapped into my manifold instead just using one port on it (ie not 'inline')?

2) Related to the above... I was seeing 300 microns with the pump running, but isolate the pump and that quickly rose (within 1 minute) to 1000 where it settled and didn't rise. I evacuated for another 3 hours and this was still the same, so figured it was fine, as it was a lengthy pipe run. I was careful to keep the caps on the pipes when installing and it pressure tested fine. Is this normal behaviour, or have I been too hasty in releasing the gas?

3) I know it will change according to many factors, but roughly what pressure should I be seeing on my manifold low-side when all the gas is released into the system? Just as a peace-of-mind check.

4) I couldn't find imperial sized insulation. For 1/4" (6.35mm) and 3/8" (9.52mm) copper I ordered 6mm and 10mm armaflex. The 6mm fits great, but the 10mm is pretty loose on the pipe. A bit concerned it will not be effective !?

5) Insulation again - how far up into the indoor unit do you insulate with armaflex? My indoor unit came with both pipes held loosely together in some sort of foam. I installed it as-was and then stripped what I could off the pipework that was external, and replaced with armaflex up to the hole in the wall, but the internal pipe is still just loose in the original stuff.

6) Last one - I did have to re-do the flare a few times to get it to seal. Eventually I just nipped it up a bit extra on the torque wrench, and this worked. Especially on the 1/4". I have the proper eccentric 410a tool and oiled the outside of the flare, but when the tool completes a flare it leaves 'ridges' in the copper at 180 and 360 degrees, where it snaps off when it is done. Could this be causing a problem? Or do you generally just need an extra turn on the wrench (18 & 42 nm I think it was).

Cheers

Reptile

Hello David

I must say that I have never come across an eccentric flaring tool that failed to do it's job correctly if it was used right.

Also, you say that you connected your gauges to the suction service valve and then applied a vacuum pump - did you also connect to the high side? if not, how do you know you had a complete circuit and obtained a deep vacuum prior to releasing the refrigerant?

As you can see from the replies you have received so far, there is a lot more to the fridge trade than DIY fitting a 'split'.

Out of interest, what is your trade?

How long do you expect your DIY installation to last?

No offence intended by the way.

[Reptile]

I suppose a motoring equvalent would be that you are an uninsured driver with no mot speeding down the road, and we are paying the extra premiums and having to suffer speed cameras.

Jon

Jon, how odd that I used the same analogy whilst ranting above.

But, i disagree - the uninsured driver is hurting everyone else in the pocket directly. I am not - it matters not to you people whether I install my own gear or not. Had I been able to get a quote for labour for anything even near half of the purchase price, I would have done, but those people who can, will always have a go. And for the record we are grateful of advice on forums like this, from people like Nike and yourself. But don't for a second think we are not giving out equal advice on our professions on other forums.

Mine is sat here now working a treat! Again I ask why (other than the 'law') you lot are different to any other profession out there?

[Reptile]

Hello David

I must say that I have never come across an eccentric flaring tool that failed to do it's job correctly if it was used right.

As above, it seemed to be misaligned.

Also, you say that you connected your gauges to the suction service valve and then applied a vacuum pump - did you also connect to the high side? if not, how do you know you had a complete circuit and obtained a deep vacuum prior to releasing the refrigerant?

I dont My unit doesn't have an accessible high side port. Nor is that in the installation instructions.

As you can see from the replies you have received so far, there is a lot more to the fridge trade than DIY fitting a 'split'.

I don't doubt it - big up yourself - but all I am trying to do is, a DIY fitting of a split.

Out of interest, what is your trade?

I didn't say I had a 'trade'. (But then, what is a 'trade')

How long do you expect your DIY installation to last?

Well, assuming I have pulled a decent vacuum, and it doesn't leak (which it didn't when pressure tested), then I expect it to last as long as a professionally installed unit (or longer, if if the professionally installed unit was installed by a 'professional' as described above, that skimped!)[/quote]

No offence intended by the way.

None taken I wish i'd had this volume of replies to my original questions, I'd be a 'tradesman' by now

[Contactor]

Fitting a split is hardly an advanced engineering project, it can be done correctly by anyone with basic DIY skills, with or without F-Gas certification.

[Reptile]

You might consider it high-horse but when we have invested a fair amount of time and money to enable us to work legally within the law of the land we do a get little peeved when others, such as yourself, are able to simple ignore it without penalty.

Sorry to return to this, but I think there is the difference. I would never do this for profit, on anyone else's property, but this is my own house.









Thankyou Contractor. I have to say, so far, replies by me = all. Replies to any of my questions, = Zero.

[Brian_UK]

Last week my car went in for its MOT, and failed. I did the work myself, saving myself a bundle. The garage retested it for me, it passed. I fail to see any major differences here. Those mechanics have also invested time and money sitting courses and training.

Now consider the situation where you had said it had passed and put it on the road with an unauthorised MOT ticket.

Sorry to return to this, but I think there is the difference. I would never do this for profit, on anyone else's property, but this is my own house.

You seem to miss the point slightly I believe. The fact that you can do the job, with the correct tools, is not the crux of the matter. It is the fact that you are, according to our knowledge of the regulations, handling hazardous waste illegally.

Yes, a DIYer could install a DIY split bought from a store as sold but, you have not done this. You began installing pipes and fittings to make a pressure circuit which brings you within the regulations.

Thankyou Contractor. I have to say, so far, replies by me = all. Replies to any of my questions, = Zero.

You should know from your other forum usage that threads will often travel sideways before getting to the end.

[lawrence1]

Maybe the Air Cond manufacturers in UK should do like most manufacturers do here where you don't get warranty unless the appropriate Arctick 'L' Gas Licence is on the warranty/commissioning form.
No license,,,no warranty.

[Reptile]

Now consider the situation where you had said it had passed and put it on the road with an unauthorised MOT ticket.

I was referring to the situation where someone (you? - cant remember) said they would not commission an install someone had done the DIY on. I was querying why, when you can do the work on your car yourself and have it 'signed off'.

You seem to miss the point slightly I believe. The fact that you can do the job, with the correct tools, is not the crux of the matter. It is the fact that you are, according to our knowledge of the regulations, handling hazardous waste illegally.

I've already stated, by the letter of the regulations, I may well (I don't know them) be acting illegally.

Is 410a hazardous?

What do B&Q units run on? How does this differ to what I'm doing?

Did you read my comment above about hiding behind a 'legality' smoke screen? Exceeded the speed limit lately? Would you like me to reprimand you on it?

Yes, a DIYer could install a DIY split bought from a store as sold but, you have not done this. You began installing pipes and fittings to make a pressure circuit which brings you within the regulations.

Forgive my ignorance, but how does that differ to a B+Q jobbie? Surely they run a pressure too?

You should know from your other forum usage that threads will often travel sideways before getting to the end.

Yep - sideways is OK, how about some answers to the questions I've posed
Lets start with who said they would not commission a self-install system... who was that? I vaguely remember it was a mod... I am intrigued as to why...




Lawrence - That would have deterred me. I'd take the risk. 500 quid for a system I can install myself, or 1200 quid to have a 'tradesman' come and do what I could do... I could buy it twice over and still have change! Sorry......

[Reptile]

How long do you expect your DIY installation to last?

Frank

Can you clarify why my installation would not last as long as one installed by a 'pro'?
In other words, what would a 'pro' have done that I haven't done?

Cheers

Reptile

[frank]

I didn't say how long it would last, I asked you how long do you expect it to last
By your own admission you may have been a little hastie in releasing the gas and you have lost some
Did you replace this gas or are you running with a short charge?
Your readings on the gauges during evacuation could indicate either a leak or moisture in the system
These things would have been picked by a Pro and rectified

[Reptile]

I didn't say how long it would last, I asked you how long do you expect it to last
By your own admission you may have been a little hastie in releasing the gas and you have lost some
Did you replace this gas or are you running with a short charge?
Your readings on the gauges during evacuation could indicate either a leak or moisture in the system
These things would have been picked by a Pro and rectified

In asking that, what I believe you meant was that it won't last long as it was a DIY install. If that isn't what you meant, then I think the answer is very obvious: I think it will last the same as every other split type air conditioner out there. Why wouldn't it?

Upon further thought, the miniscule amount of gas I lost when releasing the vac gauge, would have happened anyway, when I disconnected the manifold. I'm guessing a split second of gas loss is OK without recharging, otherwise you'd have to recharge every time you attached/release a manifold. Also it came charged for 0-15m pipe length. Mine is 7m, so I have room to play. If I'm not right in my thinking here, please correct me

I didn't say I had been hasty - I was querying the behaviour of the vacuum gauge - something that has already been cleared up above. My vacuum held fine at 1000 microns. Even so I reflushed with nitrogen, and vacuumed again (for too long apparently), to be doubly sure. I've read plenty of times on here than 1000 microns held is fine. If you disagree, please do give me your thoughts.

OK - so what would a pro have done, in that situation? Apart from nitrogen test again and further vacuuming? Englighten me I'm genuinely interested... it might happen again next time. Educate me

[Quality]

it sounds you have done what anyone has and would have done so no trouble there - don`t listen to the gripe just enjoy your install

[Brian_UK]

Is 410a hazardous?

What do B&Q units run on? How does this differ to what I'm doing?

Forgive my ignorance, but how does that differ to a B+Q jobbie? Surely they run a pressure too?

All refrigerant gas is classified as Hazardous Waste.

B+Q et al normally come with sealed connecting tubing with one shot connectors. There is no pipe preparation required.

I have just put in my first MHI split unit, which went well overall, but I have a few questions which I'm not going to find in the documentation, so thought I'd keep them all together in one place. Apologies if they are a bit random or daft.

1) In the evacuation process I had my digital gauge inline inbetween the manifold low-side and service valve, and the pump in to the centre port of the manifold. I had to see positive pressure when releasing the gas before I could remove my gauge, and lost some gas in the meantime. What is the best configuration and process to use when evacuating? (idiots guide). Should I have my gauge tapped into my manifold instead just using one port on it (ie not 'inline')?

2) Related to the above... I was seeing 300 microns with the pump running, but isolate the pump and that quickly rose (within 1 minute) to 1000 where it settled and didn't rise. I evacuated for another 3 hours and this was still the same, so figured it was fine, as it was a lengthy pipe run. I was careful to keep the caps on the pipes when installing and it pressure tested fine. Is this normal behaviour, or have I been too hasty in releasing the gas?

3) I know it will change according to many factors, but roughly what pressure should I be seeing on my manifold low-side when all the gas is released into the system? Just as a peace-of-mind check.

4) I couldn't find imperial sized insulation. For 1/4" (6.35mm) and 3/8" (9.52mm) copper I ordered 6mm and 10mm armaflex. The 6mm fits great, but the 10mm is pretty loose on the pipe. A bit concerned it will not be effective !?

5) Insulation again - how far up into the indoor unit do you insulate with armaflex? My indoor unit came with both pipes held loosely together in some sort of foam. I installed it as-was and then stripped what I could off the pipework that was external, and replaced with armaflex up to the hole in the wall, but the internal pipe is still just loose in the original stuff.

6) Last one - I did have to re-do the flare a few times to get it to seal. Eventually I just nipped it up a bit extra on the torque wrench, and this worked. Especially on the 1/4". I have the proper eccentric 410a tool and oiled the outside of the flare, but when the tool completes a flare it leaves 'ridges' in the copper at 180 and 360 degrees, where it snaps off when it is done. Could this be causing a problem? Or do you generally just need an extra turn on the wrench (18 & 42 nm I think it was).

1. You've done what most people would do with limited access to the system.

2. Did you pressure test to the required pressure? About 620psig for the strength test.
The vacuum reading will often be lower when the pump is running and is 'one of those things'; isolate the pump and watch the gauge, as you did. 1000micron is OK, a bit lower should have been achievable but depends how good your pump is.

3. You need to relate the temperature of the system at the time to the pressure. Check with a Pressure Temperature chart or your gauges may have temperature scales on them to give you a rough idea.

4. As long as the lagging is vapour sealed there shouldn't be any problems with condensation inside the lagging.

5. The manufacturers' insulation should be OK for the job otherwise they wouldn't fit it. Once again a good vapour seal will prevent problems.

6. I think that you have had that one covered already.

Lastly, some people won't commission others work because they do not know the history of the installation. The last man to touch it is responsible for the whole system.

[Reptile]

Cheers Quality - I am enjoying my install Loving it in fact - its been blowing 10 degree air at me today as I've been dashing round installing my next 2.

[Reptile]

Brian

Cheers for the reply.

All refrigerant gas is classified as Hazardous Waste.

Is it though? I thought R410a was Ozone friendly? By the same logic should my Gillette Spray not be classed as Hazardous waste? Serious question...

B+Q et al normally come with sealed connecting tubing with one shot connectors. There is no pipe preparation required.

You can also buy these types of pipes/fittings for splits, but I have read they are LESS reliable than flares.

Question: I was told in no uncertain terms earlier in this thread that I was acting illegally. If I install a mini-split, with pre made pipes, therefore removing any making of pipework by myself, ala a B&Q jobbie, am I still acting illegally?

1. You've done what most people would do with limited access to the system.

So, what you are saying is, I've done basically what a general 'pro' would have done, but at 500 quid less per unit?

2. Did you pressure test to the required pressure? About 620psig for the strength test.
The vacuum reading will often be lower when the pump is running and is 'one of those things'; isolate the pump and watch the gauge, as you did. 1000micron is OK, a bit lower should have been achievable but depends how good your pump is.

My pump is a 5CFM, brand new. But my install was lengthy. 8m or so. I pressure tested to just shy of 40 bar, wound that down to 25 for an hour, and 10 bar overnight. You can say that isn't enough pressure if you like, but it was enough for me, on my first go.

So, after 30 posts of rantings and slaggings off, and being called ridiculous by your forum members, "it would have been in your training", and being told a pro would do things properly, your explanation of my issue is "one of those things". Sorry, but, Brilliant

Lastly, some people won't commission others work because they do not know the history of the installation. The last man to touch it is responsible for the whole system.

And what about the mechanic that passes my car after:
I've fitted a new suspension joint
Apprentice at quick-fit has fitted a new tyre
His own employee has replaced my CV joint
?

What about the satellite engineer that goes out to realign a dish, that may or may not fall off the wall next week?

Come on... What is so special about your line of work, that makes it necessary for me to pay you to drill holes in my wall, mount trunking, bend pipes, push on insulation, and sit big chunks of metal on brackets? ALL of which I can do, for a damn sight less than you will charge. Furthermore, what is so hard about all of that to check and verify?

If you want to kid yourself that installing a split holds more responsibility than MOT'ing a car, regardless of who had done the work, which is going to travel at 70mph, then go ahead.

Do you know Brian, that the first post I read on here, was a genuine question, probably about vacuuming, and the reply from one of your members was "plenty of fridge tech's in your yellow pages". Well if that is the best advice this forum can offer to someone seeking help, it may as well not exist! Elitist, moi?

Perhaps you should consider a banner, stating that no-one should post unless they are fully trained in 'whatever bit of paper is required that month'. I wouldn't have done then. Perhaps I wrongly assumed a forum was there to offer advice and help

Regards

[Brian_UK]

Well, we've tried but we obviously aren't up to your standards so I think I'll give you a miss from now one. I have better things to do.

Enjoy.

[Reptile]

Asked the wrong questions, did I?

[carl simpson]

because we know what we are doing ................and by the if your flares do leak again how are you going to re gas the system because you carnt just go in a shop and buy some refrigerant also has your condenser enough gas for your pipe run you have attempted

[Reptile]

Not sure where to disect this to be honest.

because we know what we are doing ................and by

So do I

the if your flares do leak again how are you going to re gas the system because you carnt just go in a shop and buy some refrigerant also has your condenser

Why not, where do you buy yours?

enough gas for your pipe run you have attempted

Pre-charged for up to 15m my friend. They all are - thought you'd have known that !!

[Reptile]

With the total wall thickness (plaster skim to brick) of a new house at 33cm, why do MHI make the pipe terminations of the indoor unit 32cm? Doesn't arf make life hard work!!

[Contactor]

You may find it easier to leave the pipes under the unit and make your connections there.

This will be better if you need to get to them for leak testing or to re-make the joints.

[Contactor]

How did you get on with the drain, did that make it through the wall?

[Reptile]

Yeah the drain was OK - hung out by about 1.5" or so. Ended up bending it down and fixing it into the trunking by means of an overflow clip, then straight into an overflow pipe.

The 1.4" pipe hung out about the same so was ok. The 3/8" I could have just got to, probably, but ended up just attaching a flare inside, and sticking it through the wall with 1.5m of pipe attached, and bending (by hand - no room for bender). Tomorrow will tell if its good or not.

Didn't want to keep the pipe inside, as I'd have to have a foot or so of trunking on the inside. Heard many times of "back to back" installs, is it just MHI that make it so hard?

[Tayters]

If possible, cut the flare connections off the indoor unit, braze on a long bit of pipe then poke the whole lot through the wall with some lagging.
That way no flares that could leak in time to cause you grief.

Cheers,
Andy.

[Reptile]

I'm sure that would be the best way, no doubt, but I can't braze. Well, I have never brazed anyway.

Just seems odd they would design the pipes to this lengh. 3" longer i'd have been fine. 6" shorted I'd have jointed them inside.

[Reptile]

Any answers to my questions Brian?

[raz5]

After following this thread with interest I have to say "Well done" for reading up and reading up before attempting what can be a dangerous and mind bending task for DIY with no previous experience.
I think the Fgas regs that have been rammed at us along with ozone and greenhouse effects have made us all cynical to comprehend that someone can actualy take the time to study and know whats right and wrong before even attempting the dark arts of an install. And your asking questions that many of us may have asked in our earlier nieve days

Its a pity more DIY fridges dont follow your example and reading up before making sometimes fatal mistakes thinking they can do it .

As my teacher once said, what you learn in the sterile confines of this classroom is nothing to real world outside the door but follow the basics out there and at least you will not hurt yourself or others which you seem to have grasped from the beginning.

Well done ... and hats off for looking and learning and i bet you are over the moon at the brass you have saved

[Reptile]

Thanks Raz5 - blimey what a refreshing attitude.

I know I've been an ass on this thread - but no more so than every other ass than would rather put me down than try and help. And again, very sadly, that includes the mods.....

Every one of my questions were ones that I wouldn't find on this forum and by that nature they were silly, newbie questions!

It has been mind bending, and I've already admitted that I was in a unique position of being able to lay my hands on whatever I needed. I wouldn't attempt it now without this. I don't even know if my latest install has been successful or not. Tomorrow will tell!

Again I really do feel that the vast majority on here are bitter that the 'trade' (god I hate that word) is being simplified. What about me? I'm IT tech for the Government... but do I bitch about PC world "tech-guys"? No - I offer simple and free advice on the internet to those that need it. I have never replied with "Your 2 years at college, 4 years at Uni, and subsequent 5 years of ball-bending courses would have covered that!"

Chill...... out........

Brian?

[lawrence1]

Reptile,
You're name wouldn't be Wayne Kerr by any chance.

[sumsor]

Hi Reptile,

god on you for trying to get all the right information before installing your own a/c unit. There's really nothing to it, the whole procedure is in depth explained in most good installation manuals.
You have to understand though that most of the guys in this forum have done their apprenticeship and sat a few licences on top.
Here are you, asking for free advice....
Refrigerants and high pressure, Nitrogen testing are dangerous and should only be handled by trained technicians! If you do some research on it, you'll see my point.
I've just been to a job where the "professional" had to recover refrigerant out of sixteen Daikin units (approx 200 kg R410a) because he didn't know that he had to use a vacuum gauge.
You shouldn't be so sarcastic about the replies you got, take the good advice and forget about the rest.
Some of us have to spent quite a bit of money to pay for all the licences that come with the trade and might get a bit touchy about DIY installations.

Hope you don't have any trouble with your installation though, a service call out to a DIY installation is usually very expensive, there's obviously no warranty to cover the cost.

All the best Dude,

Sumsor

[Contactor]

DIY splits will never kill or simplify refrigeration.

People who only fit splits are not refrigeration engineers, despite what they may think.

DIYers can declare war as far as i'm concerned.

[lawrence1]

sumsor,
well spoken.

[Reptile]

I kno what you mean, but I'm gonna do it anyway... in fact I'm in the middle of doing it, so surely a bit of free advice, or a few Q's is no skin off anyones nose... it has taken them all longer to insult me than it would to answer a few Q's.

Is it common for a vac pump to overheat? Mine is sat pumping with the sun beating down on it, and just turned off and refused to start for 10 minutes. Have tried to shelter it a bit now.

Regards

Wayne

[exotiic]

Can I ask, if there is a warranty issue with the unit will you be proud to tell MHI that you installed the unit yourself which would void any warranty they would otherwise be liable to provide?

I am not stating that your installaiton would be case for fault, but if a component were to fail, either by fault of your own or not?

[Reptile]

Interesting question! (I'd have rather known if you've ever had a vacuum pump overheat, frankly, but...)

I have no idea what the warranty situation is to be honest. I'll look into it. If it was going to void my warranty, then fairly obviously no, I wouldn't ring Mitsubishi and tell them.

But at the start if someone had said (ballpark) £3k for 3 units with warranty, or 1.5k without, I'd have taken my chances!

My other units have gone in fine guys. Experienced the same issue with the vacuuming, ie, it will pull to 300 but then rise to 1000 when the pump is switched off, regardless of where the gauge is installed, how long its been done for. I tested pulling a vac on just the gauge and a 1m pipe, and it did exactly the same thing... so I can only assume the pipes are no good at holding a vacuum.

My 2 installs this week have gone flawlessly flare-wise, despite having to do one 'through' a wall (see above), and one at height, so I must be getting better. Still got the 'ridges' due to the flare block not aligning, guess they get squashed out when I torque up.

I think thats pretty much it for me then, barring failures. So unless anyone has got any questions for me, or Brian has got any answers for me, I guess I'll sign off, go 'chill', and cross my fingers

[Contactor]

I've never known a vac pump overheat, I didn't even know they were thermally protected.

Is it dual voltage, is it tripping the mains, is the supply a radial or ring final, is it RCD protected?

[monkey spanners]

My vac pump has cut out twice, both times i was in a plant room at well above ambient temps. On thing to be carefull of is if the pump stops the vacuum in the system sucks the mineral oil out of the pump into the system, this is very bad.

Just out of interest and for the purposes of comparison google 'hvac forum' and post your original question on there and see what response you get.

Jon

[Reptile]

Not sure on most of those, but its a modern house and it is not tripping the RCD. It is a UK pump, new.

Changed the oil (even though it had only done 1 evac), and it was still doing it later on when the sun had gone. Tripped after 15 mins, shut down, obviously reduced vac as the line was still open, and then restarted itself after 5 mins! Was too hot to touch.

Is that knackered too? Still confused about the vacuuming. Exactly the same symptoms on all 3 of mine.

I don't think I'm doing anything wrong, but for the sake of it, I'll detail it. Not that I expect any responses, either that or I'll make an utter berk of myself - maybe Brian will reply then

I always start by opening the little knob thing for 2 mins, then closing. Vac for 1 hour or so. Using the 1/4" port on the pump that fits my pipes... other 2 capped with plastic cap things... winding handle fully open... Using various pipes - tried them all, mainly pipes from my manifold / nitrogen kit. All installs fully pressure tested.

Using any of the following:

Method 1: Vac pump to centre port of manifold, high side closed, low side open. Low side port to "vac" port of VG64. "aux" port of VG64 (inline) to service valve of outdoor unit.

Method 2: Vac pump to centre port of manifold, high side closed, low side open. Low side port to service valve of outdoor unit. VG64 "vac" port connected to extra port on centre port of manifold (not inline).

Method 3: Vac pump to VG64 (inline) to service valve of outdoor unit.

All methods get down to 300-400 microns and then stop. But wind the pump in, with it still running, and it shoots up to 1000-1200 microns, no matter how long its been going. Then it rises very slowly - 50 microns every few mins.

How on earth do people get it to hold 500 microns?

As I say, tested my pump just to the "vac" port of the VG64, and it does exactly the same, so nothing to do with my installs I'm guessing.

Done now anyway.... but would still like to know.

Regards



Monkeyspanners, I would suspect heat, but it happened later on too, in the shade. Don't fancy another forum battle now, its done anyway. Whenever it happened it vac'd right back down to circa 350 anyway... :s