Advice on Inverter Purchase/Install

[mick2me]

Can anyone advise on this.
I have been looking at the Mitsubishi SRK**ZD Units.

I intend to do all the heavy work of installing the units, pipe runs and electrics, then get a refrigeration engineer to vac out and commission the units.

Any advice on Mitsubishi or alternative units would be appreciated.

Am I right for going with a unit with 410a?

[Brian_UK]

Welcome Mick, sparkies always

Using R410a seems the way to go now, it does make the units a bit smaller for the output so there is a gain there.

Can understand your suggestion of installing yourself but have to ask the question:- Do you know how to braze and the requirements for doing refrigeration pipework?

[Andy AC]

Good choice of unit, great performance and value for money. Ive just ordered one for myself -just a standard srk40hd though.
Only down side is that on the smaller units - up to srk50
wiring the interconnect when machine is on the wall is a real pain in the wotsit.
R410a not a problem if right tools and methods used.

No offence Mick, but over the years I have noticed that sparkies and a/c systems don't mix well !

Good luck anyway mate

[mick2me]

Thanks for the welcome and prompt replies.

In a former life I installed Freezers and cold rooms for a large food chain in the midlands. The rerigeration side was dealt with by our fridge engineers.

Are you saying that these units will require some brazing work? (If so the engineer could do this.) I thought they would be flared at both ends of the pipes?

Also I have read that the pipes need connecting by means of a torque wrench, is this true?

There are easy fit units, that I have considered, with clip together flexible pipes, but I am not sure how good the actual AC units are themselves.

[mick2me]

Good choice of unit, great performance and value for money. Ive just ordered one for myself -just a standard srk40hd though.
Only down side is that on the smaller units - up to srk50
wiring the interconnect when machine is on the wall is a real pain in the wotsit.
R410a not a problem if right tools and methods used.

No offence Mick, but over the years I have noticed that sparkies and a/c systems don't mix well !

Good luck anyway mate

Andy

I noticed the same thing with plumbers

I did struggle to find many suppliers for the SRK or similar units, so that I can shop around.

I will get the supplier to make up the pipes to my measurements, when I order the units.

[Brian_UK]

Mick, if you are installing with a short pipe run, less than the length of a coil of copper then you could get away without brazing any joints.

R410a does require dedicated flaring tools and the use of a torque wrench.

I will get the supplier to make up the pipes to my measurements

That is always an option assuming that they will do that for you.

[mick2me]

Thanks Brian

So brazing is for Pipe joining.
I expect the pipe run to be no more than 5-6 metres.
So just flared connections?

Reading the requirements for installing units that run on R410a is an eye opener!

http://www.bdt.co.nz/comfortmaster/d...410a_guide.pdf

[Makeit go Right]

Suggest:
a) Make sure you keep the pipe ends sealed with some tape to prevent moisture getting inside, until the fridge engineer shows up to make the unit connections etc.

b) Read the install manual as to required space around the units when mounting them.

[mick2me]

Suggest:
a) Make sure you keep the pipe ends sealed with some tape to prevent moisture getting inside, until the fridge engineer shows up to make the unit connections etc.

b) Read the install manual as to required space around the units when mounting them.

Thank you

Any advice on how good these are?
They say "Flexible lines. No vacuum pump or engineer required for installation."?

[andy bailess]

mick if your going to use the above flexi pipes make sure you wear gloves and can push the pipes on with considerable force as they tend to loose refrigerant.

[Brian_UK]

Forgive the question Mick but are those flexi pipe suggested for use with R410a?

Also, does the a/c unit come with the correct fittings to accept those pipes?

Any flexi pipe I would consider dubious for use on R410a due to the higer working pressures involved, a proper brazed or flared joint every time.

[mick2me]

Forgive the question Mick but are those flexi pipe suggested for use with R410a?

Also, does the a/c unit come with the correct fittings to accept those pipes?

Any flexi pipe I would consider dubious for use on R410a due to the higer working pressures involved, a proper brazed or flared joint every time.

I thought the same Brian, being aware of the Pressure of 410a.

But here is the spec sheet for a 'Quick Couple' 410 inverter.

http://global-cooling.co.uk/aircondi...cification.pdf

[Brian_UK]

Thanks Mick, I stand corrected, bemused but advised

[mick2me]

You've got me wondering how good these connections are. I dont see how you can connect them without a small amount of air getting into the system. And what effect would that have?

There must be a lot of people installing these systems from DIY stores.

[Brian_UK]

Having a closer look at those quick couplers and it does look as though they are made a bit stronger than the ones we may all have been thinking of.

The older ones, R22 etc, were simply a screwed connector, male/female ends of course, with a thin metal seal over the pipe ends. You had to start the threads and then crank up the spanners as fast as you could !! You didn't normally have any air gettting into the system because you were busy losing gas through the joints that you were frantically trying to do up.

The joints shown in your picture seem to have a more psoitive action. It looks like you push the female pipe end into the male unit socket and perhaps lock it together somehow.

The lever by the guys left hand seems to have a cam attached which will make the final connection thereby breaking the pipe seals and closing the joint.

Mind you, you won't find them on a Mitsi

[frank]

The joints shown in your picture seem to have a more psoitive action.

Hi Brian

Are you just testing the other Brian's theory about the letters being jumbled up

[Brian_UK]

No Frank, I've just spotted it myself and was about to correct when I saw your post.

Now I don't know whether to correct or not; I had better leave it otherwise your post will look as bad as mine

[mick2me]

Not sure what the Letters jumbled stuff is, but anyway. I did buy one, not sure if I did the right thing here but I bought...

DAIKIN INVERTER R410A SPLIT SERIES


FTXS25CVMB WALL INTERNAL WALL MOUNTED UNIT

RXS25CVMB OUTSIDE UNIT
AIR PURIFYING FILTER
REMOTE CONTROL & HOLDER


AVAILABLE FEATURES INCLUDE
AUTO.DRY.COOL.HEAT.FAN
OUTDOOR UNIT SILENT OPERATION TIMER & HOME LEAVE OPERATION

Looks like it will be a flared connection afterall.

Spec can be seen at...
http://www.easyventilation.com/image...unted_spec.pdf

[frank]

DAIKIN INVERTER R410A SPLIT SERIES


FTXS25CVMB WALL INTERNAL WALL MOUNTED UNIT

RXS25CVMB OUTSIDE UNIT
AIR PURIFYING FILTER
REMOTE CONTROL & HOLDER


AVAILABLE FEATURES INCLUDE
AUTO.DRY.COOL.HEAT.FAN
OUTDOOR UNIT SILENT OPERATION TIMER & HOME LEAVE OPERATION

Good Choice.

But these don't come with quick couplers on the pipework. You will need to pressure test and vacuum before opening the stop valves.

[mick2me]

I will pick this up in a couple of days. When I get a chance to look at it I will sort a position out for the outside unit. I may get some brackets and fix it higher up on the wall to minimise ingress of dust.

I am still undecided as to it serving the lounge or bedroom.

I am a lot happier with the flared connection too.

I have been reminded by SWMBO that I have a number of jobs to complete before I start this one.

The spec does not give the length of the interconnecting cable, but I assume it can be extended.

Once mounted and wired I will be looking for an engineer to Vac down and check final gas pressure.

[Brian_UK]

Frank, you must be getting telepathic, you can sell from afar now

[Slim R410a]

I will pick this up in a couple of days. When I get a chance to look at it I will sort a position out for the outside unit. I may get some brackets and fix it higher up on the wall to minimise ingress of dust.

I am still undecided as to it serving the lounge or bedroom.

I am a lot happier with the flared connection too.

I have been reminded by SWMBO that I have a number of jobs to complete before I start this one.

The spec does not give the length of the interconnecting cable, but I assume it can be extended.

Once mounted and wired I will be looking for an engineer to Vac down and check final gas pressure.

You dont get interconnecting cable with a proper split like you have bought, but you will need some 4-core 1.5mm.

If your using an isolator on the indoor unit then dont break the number 3. (comms)

[frank]

If your using an isolator on the indoor unit then dont break the number 3. (comms)

Good advice . Certainly don't put it through the isolator where it could pick up interference. (Crimp it seperately).

Also important is to make sure that you have a good neutral otherwise you will blow the inverter board at switch on.

[puddleboy3]

As already pointed out good choice of unit, the only thing i can throw in to the thread is i would recommend that you cut off the indoor flare nuts and braze the connections, makes a far neater job!

[mick2me]

Thanks

The electrical advice will mean more to me when I see the manual. The Piping side will be dealt with by an engineer. I hope to collect it towards the end of the week.

[Brian_UK]

Glad that it's all coming together for you Mick.

Just follow good electrical practice, as you would, and you shouldn't have any problems.

In this case you have to think about your own safety as you are your own customer

[mick2me]

Glad that it's all coming together for you Mick.

Just follow good electrical practice, as you would, and you shouldn't have any problems.

In this case you have to think about your own safety as you are your own customer

Thanks Brian.

The four core 1.5 cable (or 2.00mm if over 10m)
I have got to sort? Having read online manual I see
the no 3 connecting wire and reason for not isolating it. LIve Neutral Earth Signal.

I may collect the unit tonight or tomorrow.
There will be no doubt more Q's then

Ta'
Mick T.

[S_Line]

As already pointed out good choice of unit, the only thing i can throw in to the thread is i would recommend that you cut off the indoor flare nuts and braze the connections, makes a far neater job!

yep cant agree more, the connection to the inside unit MUST be brazed, we always Braze these as they are always either behind the unit or halfway through a wall, we have been called to many ( other installs) where these have not been brazed and had to take the whole wall unit down , braze and re install costing the customer a small fortune


Always braze the back of wall units, it takes 10 Min's max and will provide the customer with a proper job

[mick2me]

Thanks for that.

Are we saying that the connection on the indoor unit is not reliable?

Brazing does that mean that the pipes need to be charged with nitrogen?

Anyways I picked the Daikin Inverter unit up last week, and am very pleased with the quality of the units.

First question on this is regarding the pipe.

Daikin specify
GAS OD 9.5 mm
liquid OD 6.4 mm
thickness 0.8 mm

I know someone who has a coil of
1/4 X 22G- 6.35 X 0.71MM
Is this suitable?

Also Other sizes I have seen listed are Imperial?
1/4" 3/8" 1/2" 5/8"

Are there imperial sizes and metric?

What do I buy for the Daikin spec pipe?

Thanks

[frank]

Normal refrigeration quality 1/4" and 3/8" pipework will be fine.

Don't get concerned about having to braze the indoor connections, it's not compulsory and the flare joints are OK if made correctly - some engineers prefer to cut off the flares and make a brazed joint. I do it too when the flares would end up in to the wall with no future access.

As you intend to get a fridge guy in to vac out and commission why don't you get him to make the flares?

[Andy]

Normal refrigeration quality 1/4" and 3/8" pipework will be fine.

Don't get concerned about having to braze the indoor connections, it's not compulsory and the flare joints are OK if made correctly - some engineers prefer to cut off the flares and make a brazed joint. I do it too when the flares would end up in to the wall with no future access.

As you intend to get a fridge guy in to vac out and commission why don't you get him to make the flares?

Hi

in defense of flares the new offset rotary flaring gear is great, you don't even ream the pipe and provided your cutters are sharp the flare comes out like a machined flare

I will confess if the flare is hard to get at I would smear high strength lock tight on the flare mating surface, it will never leak, but be careful don't use too much, my mate says I block gomex fittings

Kind Regards Andy

[mick2me]

Thanks Frank & Andy.

I checked the indoor Unit for the first time today.
The pipes come out of the right hand side looking from the front. They terminate in the center of the unit, which is where the joint will be. If I take the pipe run in through the left hand side of the unit, there will be access to the joints by lifting the inside unit off its mounting plate.

I was suprised to see that both pipes ran in one insulation sleeve? Surely isnt one very hot and the other cold. Should they not be thermally insulated from one another?

Talking of getting an engineer?
I will make that subject of another thread post.
By which you may or may not be suprised!

[frank]

Talking of getting an engineer?

You did in your first post.

I intend to do all the heavy work of installing the units, pipe runs and electrics, then get a refrigeration engineer to vac out and commission the units.

[mick2me]

No, Frank I met an engineer the other day.

Here is my experience!

http://www.refrigeration-engineer.co...ead.php?t=5160

[mick2me]

R410a does require dedicated flaring tools and the use of a torque wrench.

Can someone explain this.

Is it a different shape of flare?

And what type of Tork wrench is used for the nut?

[Brian_UK]

In theory you are flaring a slightly thicker pipe wall and the tool allows for this by 'forming' the flare not just squeezing the flare shape out of the pipe.

The torque wrench is an open ended spanner head that fits into the torque wrench handle. The handle will 'snap' at the correct setting.

[mick2me]

In theory you are flaring a slightly thicker pipe wall and the tool allows for this by 'forming' the flare not just squeezing the flare shape out of the pipe.

The torque wrench is an open ended spanner head that fits into the torque wrench handle. The handle will 'snap' at the correct setting.

Thanks Brian, in my research I have never seen a flaring tool that specifies that it is suitable for 410 or a thicker grade of pipe?.

[mick2me]

Good advice . Certainly don't put it through the isolator where it could pick up interference. (Crimp it seperately).

Now I am wondering if I am reading this right?

Putting it through the Isolator?

I am running the 2.5mm T&E feed to the inverter back entry into a 20A rotary disconnector



Breaking live and neutral, bottom exit via flexible conduit to feed the inverter. The 1.5mm 3 core and earth leaves the inverter by the same flexible conduit, to the switch box, but is not broken by the switch. It just exits through the back of the switch into the house, running up the wall inside before rejoining the pipework on its route to the interior unit.

This allows the use of light Twin & Earth, and 3 Core and earth cable as opposed to Armoured cable.

Are you saying that running the control cable through the isolator will cause some kind of interferance?

[Brian_UK]

I think he is saying that you shouldn't put the control wire through the switch contacts, "crimp it". Ideally the control and power wires could be separated but in practice very rarely are.

However if you put them through a switch the line quality can fall and the signal gets corrupted. Depending on the make etc the control signal may be a modulated 12vdc or a modulated 120v or a carrier low voltage, so any break in the line can cause problems.

PS see other thread for flaring data

[mick2me]

I think he is saying that you shouldn't put the control wire through the switch contacts, "crimp it". Ideally the control and power wires could be separated but in practice very rarely are.

However if you put them through a switch the line quality can fall and the signal gets corrupted. Depending on the make etc the control signal may be a modulated 12vdc or a modulated 120v or a carrier low voltage, so any break in the line can cause problems.

The three core & earth will pass straight through the switch box without breaking the conductor, conductor insulation, or outer cable insulation. Though it will run parallel to the 2.5mm power supply cable for about a metre, and passes close by the switch (which would only be operated under emergency conditions).

As the entire lenghts of the three core & earth interior unit feed, will carry 240v parallel to the signal cable, I cant see it causing any more intereference passing it through the switch?

Im just wondering where running a signal cable alongside 240v cores fits with the IEE regs?

[Brian_UK]

Im just wondering where running a signal cable alongside 240v cores fits with the IEE regs?

Sorry, have the Japanese read the IEE Regs

Honestly there are very rarely problems on splits, it can be more sensitive on the VRF/VRV type kit because the data list and flow is probably greater.

[TopMechanic]

Yeah you pickup about 5% capacity fo rthe same physical size unit, and at a higher SEER rating. Drawback is , its like a loaded gun at the pressures it runs. JMO,

[mick2me]

Sorry, have the Japanese read the IEE Regs

Yes, Silly Me!

[frank]

I think he is saying that you shouldn't put the control wire through the switch contacts, "crimp it". Ideally the control and power wires could be separated but in practice very rarely are.

However if you put them through a switch the line quality can fall and the signal gets corrupted. Depending on the make etc the control signal may be a modulated 12vdc or a modulated 120v or a carrier low voltage, so any break in the line can cause problems.

Exactly Brian

BS7671 recommend a minimum seperation of 300mm between data and power cables but in practice this isn't possible on an split install. Just don't put the data cable through the switch contacts.

[mick2me]

Just a point about Earth Bonding.

I intend to run a 6mm bonding cable from the consumer unit via the flexible conduit, and earth bond the brackets and inverter assembly.
Any comments on 'Equipotential Bonding' ?

[mick2me]

Yeah you pickup about 5% capacity fo rthe same physical size unit, and at a higher SEER rating. Drawback is , its like a loaded gun at the pressures it runs. JMO,

Efficient, Powerful, and a novel method of committing suicide

[frank]

Just a point about Earth Bonding.

I intend to run a 6mm bonding cable from the consumer unit via the flexible conduit, and earth bond the brackets and inverter assembly.
Any comments on 'Equipotential Bonding' ?

Why?

The CPC within your T&E will be sufficient and the whole casing will be connected to it, therefore, so will your brackets (and the missus when she touches it ).
Equipotential bonding ensures that all metallic parts are at the same potential. Unless you are installing seperate traywork for your cables/pipes to run on then you don't need a seperate earth.

[mick2me]

Why?

The CPC within your T&E will be sufficient and the whole casing will be connected to it, therefore, so will your brackets (and the missus when she touches it ).
Equipotential bonding ensures that all metallic parts are at the same potential. Unless you are installing seperate traywork for your cables/pipes to run on then you don't need a seperate earth.

Exactly, Pointless, Bonding items together via cable link, that are themselves physically bonded together, and already a good conductor of electricity.

Bonding Soldered pipework a good example.
OTT but required by the said regs? (perhaps not 'Big in Japan')

However, as I have the cable and the clips, and it will take 5 mins, I will do it. It will look good on any inspection.

"Bull**!t", I call it!

[Slim R410a]

Mick are you getting an engineer to do all the pipework, pressure testing etc and when??

[mick2me]

I have changed the run of pipes now. Its much simpler run, One 90 bend at the Inverter one at the wall. Not a problem for me to pull the pipes in now, with the aid of a bending spring. Just like Pyro, anyone remember that?

However extesive reading here and elswhere, has convinced me that flaring pipe, ensuring leakproof system and vaccing out are a professionals job.

I am (or was) a sparky, mate, so, feel competant to mount units and do the electrics. In fact all the bits I do are probably overkill, doubling up on fixings, earthing bits that probably dont need earthing etc.

I am nowhere near that stage yet, as I have had to have the (stainless steel) brackets cut and drilled by an engineering firm.