R22 comp in R407c Citi multi

[stufus]

Hi all .
I have found myself in an unusual situation this week,after returning to work following a back injury I attended one of the sites I look after and was informed that a compressor had failed while i was absent.
The company i work for had to bring in a contractor to replace the comp.
I decided it was in my best intrests to check the system in question and to my horror found that a R22 comp had been fitted to the system which is R407c.:confused:
So this in its self has opened up a can of worms.
The unit is a 10 year old Pury-p250ymf-c
Obviously both comps use differant oil POE and mineral and with the age of the installation it's safe to assume every component is coated in POE.
So the question is what sort of damage will the intro duction of the mineral oil have on system???,it has been running for three weeks.
The comp will be replaced either way with the correct model,But is the damage done already
Being of the mind to check every part is correct before installing it,I've never had this problem before....

Your's in anticipation
Pi**ed off Stu:mad:

[charlie patt]

you may find r22 comp has been put on a ester oil as original is there a label with grade oil on it some manufactuers will tell you only diff between a r22 and 407c comp is the oil some times there is diff i would look for label first

[stufus]

I checked with Mitsubishi Charlie it's definatly the wrong comp
Original comp =HEV92FA1-YB - OIL=MEL32 = POE
Replacment =HHV92FAA-YB - OIL=MS32 = MINERAL
What im after is what damage will the wrong oil have caused to the system and the refrigerant ,such as acidity waxing etc,etc
The new comp is coming back out along with the ref charge at the expense of the contractor.
I think there is an allowable value for cross contamination of oil to 5%,but as the system is 10-11 years old will the introduction of mineral oil have a detrimental effect ?and if so how bad?
Cheers
Stu

[charlie patt]

what refrigerant is on have they used 407 with mineral comp

[stufus]

IT's a R407c system and they installed an r22 comp charged with mineral oil and re gassed system with new R407c.
There in lies the problem!!
Cheers Stu

[charlie patt]

well that comp wont last long then you will also get waxing ph faults and oilseperation the only answer is new comp flush it put some driers in and regular oil sampling if poss switch unit of imediatley until work done but it will need a flush

[stufus]

Cheers Charlie
That's what I was thinking, was just looking for another opinion.
Not the sort of headache you want when you come back to work.
If nothing else it should make for a very entertaining meeting with the contractor:rolleyes:
And just to make it interesting it's serving an office area occupied by a government body who don't appreciate down time.;)
Cheers
Stu

[DTLarca]

well that comp wont last long then you will also get waxing ph faults and oilseperation the only answer is new comp flush it put some driers in and regular oil sampling if poss switch unit of imediatley until work done but it will need a flush

Can I ask Why?

[stufus]

Can I ask Why?

Yes you can !
I did, it went like this...
Why the f**k did you put a new R22 compressor charged with mineral oil into a 10 year old R407c vrf unit and charge it with new R407c refrigerant???
Cheers
Stu

[marc5180]

I think DTLarcas post was aimed at Charlie Patt mate.

There's not much you can do now apart from obviously change the compressor install new driers and use a refractometer to check the mineral oil content is less than 5%.

Did Mitsubishi send the wrong compressor or the contractor order an R22 compressor?

[stufus]

I think DTLarcas post was aimed at Charlie Patt mate.

There's not much you can do now apart from obviously change the compressor install new driers and use a refractometer to check the mineral oil content is less than 5%.

Did Mitsubishi send the wrong compressor or the contractor order an R22 compressor?

Cheers Marc


So it was !! My bad:o
I understand it is what it is,
Wether mitsubishi sent the wrong compressor or the contractor ordered the wrong compressor is neither here nor there unfortunately.
The responsibility is with contractor to ensure the right part is fitted regardless of what was ordered or delivered.
Plus the old one had a big orange sticker on it stating POE mel32 R407c only.
While the new one was clearly marked mineral ms32 R22
I suppose the moral of the story is only use competent subbies:p
Cheers Stu

[monkey spanners]

Can you change the oil in the compressors?

Does the system have an oil seperator? I wonder if you could tap into the return line to capture the mixed oil and then pump in the sam amount that was removed.

Is the R22 comp the same as the R407C one apat from the oil type?

I wonder if it would be worth considering replacing the R407C with a R22 drop in that would be happy with the mineral/ester mix.

[Thermatech]

My understanding is that it takes 1000's hours for the mineral & synthetic oils mix to form sludge which then makes blockages.

The mineral oil content needs to be less than 5%. In this case a compressor with about 1.5L of mineral oil has been fitted & pottentialy the mineral oil is now mixed with the systhetic oil. So the mix might be about 50 / 50.
However at this stage I dont think any permanant damage has been done.
If you replace the compressor with the correct one which will have synthetic oil charge then you will have automaticaly reduced the % mineral oil but possibly not enough to get right down to <5%.

Suggest braze a schreader stub in the bottom of the compressor shell so that the oil can be drained from the compressor & recharged with synthetic oil.
Go back to site after a few weeks & measure the oil with the refractrometer & calculate the % mix of the two oils.
Drain & replace with synthetic oil.
Return after a few more weeks & repeat.
After 2 or 3 oil changes you will find the % mineral oil will get down to < 5%.

I did this many many times in the 1990's when we were doing a lot of R407c retrofits. So I know this procedure works.
1/ before installing the correct compressor pour out the oil from the compressor shell through the suction tube.
2/ remove & clean to bear metal a small patch at the very bottom of the compressor shell.
3/ pressure the compressor shell very slightly with OFN.
4/ very carefully drill a hole in the cleaned patch as close to be bottom of the shell as possible.
use a spacer on the drill bit to ensure it only just goes through the metal shell & not deeper as a precaution.
The OFN will blow any swarf out so it wont get into the compressor & cause dammage but make sure you have eye protection.
5/ Silver solder the schreader stub into the hole.
6/ Refill the same volume of oil removed from the compressor with synthetic oil & install the compressor into the unit, pressure test vac & recharge asap.

YMF-C units have a liquid line filter drier in the outdoor unit so its always a good precaution to replace when doing a compressor change.
But
Why did the old compressor fail ? did it burn out leaving acid in the system ?

Suggest always do an oil acid test & if some acid pressent install a suction removable core filter drier & use burn out filter core as per standard burn out clean up procedure.

[stufus]

Cheers Monkey spanners
I'm not to sure how this one's going to play out,IE will the contractor be made rectify it as his expense or will i be tasked with the clean up and my employer charge the subbie for it.As i've said the compressor and gas will be replaced either way.

I'm more concerned with the possible effects the oil mixture has possibly had or may have on internal components throughout the system such as lev's.transducers,solenoids,strainers etc etc
This is a new one for me i've never come across it in 17 years in the trade.
Cheers
Stu

[stufus]

Cheers Thermatech,was hoping you you'd show up;)

The procedure for the clean up is standard stuff ,was thinking about tapping in an oil connection alright.
Not to sure exactly what the cause of the comp failure was
as soon as i reported the wrong comp was installed the subbie clammed up.So facts are thin on the ground at the moment.
Personally I would have changed the drier, and I do an acid test on all comp failures, unfortunately I wasn't around.
Hopefully the damage isn't done so,will just have to get it done and keep an eye on it.
Cheers
Stu

[Thermatech]

My understanding is that the problem is oil mixture eventually forming a sludge which then causes blockages & on a VRF system with many many LEV valves & strainers all around the system this could pottentially write off the system requiring all new units & pipework.

So getting the mineral oil down to <5% is important but at this stage not desperately urgent.

Just use this as a hospital job that you can return to when not desperately busy with urgent work.

[DTLarca]

My understanding is that the problem is oil mixture eventually forming a sludge which then causes blockages & on a VRF system with many many LEV valves & strainers all around the system this could pottentially write off the system requiring all new units & pipework.

So getting the mineral oil down to <5% is important but at this stage not desperately urgent.

Just use this as a hospital job that you can return to when not desperately busy with urgent work.

Hi thermotech, I don't assume anything about anyone I reply too. Like with everyone else I have read your posts in general before replying - I hope to be as knowledgeable on VRV system as you are one day :)

But knowing that you are more knowledgeable on VRV systems than me will not stop me from asking questions when I feel that maybe I have enough reason to remain in doubt.

I thought the original reason why <5% was stipulated in the early days of retrofitting was because the oil experts did not know what would happen otherwise - not because they knew what would happen otherwise.

Floc points are routinely of concern in refrigeration plant but not necessarily in ac plant.

I feel compelled to sit on the side line out of the field of play and simply ask "Why?".

[stufus]

I don't pretend to know all in relation to oil mixing or the origins of the 5% tolerance,but is it not safe to say mineral oil should not be used with r407c due to it's R134a content.
It's under this reasoning that the original post was made.@ DTLARCA if you feel you may be able to add something to the discussion without straying to far from the point feel free.
However if you would rather sit on the fence asking, why?
I would have to enquire,WHY???:confused:
F A Qs Mixing of Oils
Mineral Oils:
Alkyl Benzenes:
In this regard you may regard Mineral & Alkyl Benzene’s as ‘Sugar’ and Polyolester’s
as ‘Salt’. Mixing any of the same broad type will not effect the overall performance,
although the resultant viscosity will charge proportional to the mix ratio. It is
important is not to mix Mineral with Polyolester unless using with traditional HCFC
refrigerants or blends of these gases. Do not use Mineral on any system using R134a
or a derivative.
These are simple refined products made direct from crude oil. Most
mineral oils utilised in refrigeration are Napthenic type oils. Viscosities
are normally rated at 32; 46 & 68 for use on most systems from -
40
0C to + 150C. Thinner viscosities are also available for very low
temperature systems.
These are synthetically produced oil with very similar characteristics
to mineral oils, however they are claimed to have improved lubricative
qualities.

Polyolester Oils:
These are fully synthetic oils produced in a totally different manner to
synthetic Mineral oils. These are the commonest lubricants for HFC
based gases. These oils use the same ISO grading system as Mineral
/ AB types. however they tend to be more viscosity stable and may
offer improved lubricative qualities to the compressor in extreme
situations.
Cheers
Stu

[Thermatech]

I dont claim to be a refrigerant oils expert.
But I do know from experiance how to carry out the retrofit process on VRF systems.

Interestingly there was the case on one site where due to very unusual set of circumstances the oil change procedure was not followed through & the systems were left to run for a couple of years with aprox 50 / 50 mix.
There were no end of blockage problems & the maintenance contractor ended up replacing all the indoor unit coils complete with LEV valves & strainers due to sludge contamination. This was an ongoing problem for a number of years at this site so it really was a complete disaster.

However I regularly work on other sites with R22 VRF equipment which was retrofitted to R407c back in the late 1990's & the systems have never had any blockage problems.These systems are currently running at arround 50 to 70,000 compressor run hrs. On these sites the oil change procedure was carried out & <5% mineral oil.

So although I am personally unable to defend the <5% mix from a technical standpoint I do tend to consider it to be a good precaution to follow in view of the pottential risk of sludge formation & blockages.

I suppose it a belt & braces approach
Better safe than sorry.

[charlie patt]

ok guys its getting a bit political i personally think and its only my opinion 407c and mineral no good it will run but for how long and with what other problems/ whatever goes wrong now will be blamed on the incorrect comp /oil weather it is its fault or no. degas it rip out the old comp flush it drier it and fit correct comp then ph test it a week later if contractor wants to keep customer fit a oil sep with a float

[DTLarca]

I dont claim to be a refrigerant oils expert.
But I do know from experiance how to carry out the retrofit process on VRF systems.

Interestingly there was the case on one site where due to very unusual set of circumstances the oil change procedure was not followed through & the systems were left to run for a couple of years with aprox 50 / 50 mix.
There were no end of blockage problems & the maintenance contractor ended up replacing all the indoor unit coils complete with LEV valves & strainers due to sludge contamination. This was an ongoing problem for a number of years at this site so it really was a complete disaster.

It could be that what was thought to have been the cause was the cause. But also it could have been a coincidence.

Miscibilities are a major concern - minerals are not miscible with the new refrigerants. But the new oils are generally miscible with the old refrigerants.

I would expect erratic LEV and heat exchanger performance if the system was 100% mineral - miscibility issues - not floc issues until lower temperatures such as applies to freezer applications.

But if there is a substantial amount of synthetic oil in the system will there still necessarily be a problem?

Even if in the end the better think to do is to replace the entire oil charge - retrofit procedure style - would it still be necessary to also change the compressor out?

[charlie patt]

it will be the only way to keep customer happy we are not taking about a fan motor out of back of a van we are talking about a specially ordered part not a out of date or no longer available part.if it was a 22 comp and the wholesaler had fitted ester then not so much of a problem right oil to right refrigerant surely its just basics?

[DTLarca]

it will be the only way to keep customer happy we are not taking about a fan motor out of back of a van we are talking about a specially ordered part not a out of date or no longer available part.if it was a 22 comp and the wholesaler had fitted ester then not so much of a problem right oil to right refrigerant surely its just basics?

You're looking at the matter from a political point of view.

I'm looking at it from the neutrality of being simply curious about the technical aspects :)

It seems to me that one oil change after a full load run and oil harvest cycle will be sufficient.

[stufus]

OK GENTS
Thanks for all your replies , much appreciated.:)
Just so we are all on the same page ,
The comp will be removed and the CORRECT model fitted and gas will be replaced as this is what the end user has paid for !
And what the subbie was paid to do !

The general consensus if I have interpreted the replies correctly is,,, that although not an ideal situation to be in it can be rectified easily enough without having long lasting or major implications.

Maybe the 5% thing is a myth,maybe it's not,but surely it's just better to err on the side of caution;)

Cheers
Stu

[DTLarca]

OK GENTS
Thanks for all your replies , much appreciated.:)
Just so we are all on the same page ,
The comp will be removed and the CORRECT model fitted and gas will be replaced as this is what the end user has paid for !
And what the subbie was paid to do !

The general consensus if I have interpreted the replies correctly is,,, that although not an ideal situation to be in it can be rectified easily enough without having long lasting or major implications.

Maybe the 5% thing is a myth,maybe it's not,but surely it's just better to err on the side of caution;)

Cheers
Stu

The most difficult task is to try find an easy method of changing the oil to get the % levels you want.

If you have say 4 litres of oil in the system of which we think there is now say 40% mineral then you would want to remove 7/8ths of the total oil charge in order than when 7/8ths synthetic is charged back in the remaining mineral oil will account for just 5%.

So in the imaginary case where the total charge is 4 we would want to remove 7/8 x 4 = 3.5 litres.

You want to seriously avoid any need for "flushing".

[stufus]

The most difficult task is to try find an easy method of changing the oil to get the % levels you want.

If you have say 4 litres of oil in the system of which we think there is now say 40% mineral then you would want to remove 7/8ths of the total oil charge in order than when 7/8ths synthetic is charged back in the remaining mineral oil will account for just 5%.

So in the imaginary case where the total charge is 4 we would want to remove 7/8 x 4 = 3.5 litres.

You want to seriously avoid any need for "flushing".
With the compressor getting replaced for the correct model with the correct oil:rolleyes:this will account for a significant portion of the total oil present,
As Thermatech suggested a schrader will be tapped in to the sump for future use in oil removal and charging.
And as I said earlier , I will err on the side of caution and carry out regular oil changes and acid test's until such time as the percentages and Ph levels are acceptable.
Hopefully all will work out ok and no issues arise in the future.:D
Thanks again
Cheers
Stu

[DTLarca]

As Thermatech suggested a schrader will be tapped in to the sump for future use in oil removal and charging.

Yes - excellent idea :)

[stufus]

Yes - excellent idea :)
I better spin up the new comp before I install it as I don't think Mitsubishi will honour a warranty claim for a comp that was DOA if I drill a hole in the arse of it .:o
Cheers
Stu

[monkey spanners]

Are the mitsi comps or copeland ones?

If they are copeland then you will be able to buy one with an oil fill port and sight glass already in it.

[stufus]

Are the mitsi comps or copeland ones?

If they are copeland then you will be able to buy one with an oil fill port and sight glass already in it.

To the best of my knowledge they are mitsubishi built,but don't quote me on that;)Could very well be rebadged.
Will look into it.
Cheers
Stu

[Thermatech]

To be honest I have no idea exactly how long it would take for the new oil in the compressor to become fully mixed with the old oil in the system.
The thing is 99% of the oil gets seperated out at the oil seperator & gets dumped into the suction accumlator. Most of the rest of the oil is in the accumlator.
The accumlator is in two sections.
A very small amount of oil ends up going arround the system. This eventually gets back to the accumulator & is transfered from one half to the other half via SLEV lev valve.

So its difficult to estimate how long it would take to fully mix. I guess if you had some time it would be an interesting excercise.

Perhaps we should make an open invitation to refrigerant oil experts to provide upto date technical guidance on this matter :D
Perhaps there is a technician working in an oil manufacturers laboratories
some place in the world who has done lots of test rig trials with motitoring & evaluations of oil mixtures in refrigeration systems ?:cool:

In the mean time I would continue to suggest as above:)

[mad fridgie]

May I suggest you contact
Fri3Oil System (http://www.refrigeration-engineer.com/forums/member.php?u=37723) he seems very knowledgable on oils, mixtures and contamination

[stufus]

May I suggest you contact
Fri3Oil System (http://www.refrigeration-engineer.com/forums/member.php?u=37723) he seems very knowledgable on oils, mixtures and contamination

Spoke to Fri3oil via e-mail earlier today.
Waiting to see how the in house politics plays out before taking any further action.
Cheers
Stu