30 ton split R-22 to 410a

[Jimmyhat 597]

Sounds like a job bid by someone with just enough knowledge to put the car in Drive but not enough to check the brakes. Any AC DX job with an Accumulator or an Oil sep. Is a bad system wich has been band aided already suggest T&M only

[allstar08]

Did you hear "looks as if Trane is having problems with their 15 ton scrolls" directly from Trane? Or is this wishful thinking/supply house rumor?

I think your words above would have more street cred if these 15 ton scroll failures were occurring in brand new 410A systems (the entire system, including evap, coils, linesets) at a rapid pace, systems that had not been converted from R22. Perhaps they are, but I personally would be asking that question were I told "we're seeing a lot of failures with these 15 ton scrolls and the factory is running of them" with no other qualifiers.

In your case I'm wondering if some time and $$ spent on RX11 flush may have made the difference between your scrolls failing or staying alive.

I heard it on this site and around the water cooler. I know what you are getting at, and I see your point. None the less I have heard mutterings about the compressors made south of the border and how they perform running 410. Why else would it take over a month to get replacements? I can call my local supplier and can count on my right hand how many times they have not had a compressor, including the three of these I have ordered.

If you read the Trane installation manual it does not recommend using R-11 flush kits.

[allstar08]

I guess that that my prayer for you is a little too late. But now you must continue with a little hope.
As for the failure this was to be expected. As the others have stated, R-22 and 410A components should never be mixed. The equipment is not interchangeable. You now have a monster out of control.
It sounds like you have a tandem scroll compressor arrangement which will normally require replacement of both compressors. Sounds easy enough Huh?

I don't think so. Your compressor failed because a lack of oil. This was evident from the noise and the locking up of the scrolls. Now you will have to first clean up the mess. There are now fine metal micron fragments in the system which must be removed or expect another quick failure. You know the routine with a high capacity clean up suction filter/drier. You will also need to perform an acid test.

Having left behind some mineral oil and mixing with POE oil has resulted in the form of two liquids. This is a direct result of oil loss.

As for the remedy you will need to consider operation in a part loaded condition. The installation of a hot gas bypass line will need to be installed so that proper circulation of oil can be maintained and returned to the compressor. Liquid line size will need to be evaluated so as to maintain a minimum velocity of 260 feet per minute and a recommended maximum of 400 feet per minute. Suction Line size may need to be at least 1-5/8 or maybe even 2-1/8 so as to maintain proper oil return

REMEMBER: With 2 stage units you must look at the suction line velocity at reduced capacity to insure velocity remains above 1000fpm on suction risers. If it does not, reducing the riser size by one size will correct the problem


I will send you a sizing chart as an example for your use in the next post:
If you want I can email it as an excel file.

In addition I would remove the suction accumulator and install one sized correctly for your application. It sounds like you have a single circuit with one TXV.

The other problem that you will have is that when one compressor is running it will have the tendency to draw oil from the compressor which is off by means of oil misting. You will have to install a crankcase heater and possibly two so as to prevent this from happening.

The head pressure will also need to be maintained at a minimum set point and controlled by a speed controller such as a Penn/Johnson VFD 66 Drive and with the use of a pressure transducer P499.

I can go on but not tonight.

Troubleshooting is not part of the repair..............understand the symptoms and you will find a solution.

I can tell you love this stuff. Thanks for the input.
System has hot gas bypass and two txv's. Each txv has a check valve and a liquid line solenoid.
Compressors come with 1 1/8 equalizing line between them. There is a head pressure control, a Trane original, a damper controlled by an actuator on top of the fan discharge.

[Cmstech]

Never let the customer, your company, or anyone else cause you to sacrifice your integrity and quality of work.

[Armament]

I find this thread very interesting. Everyone seems to be incredibly worried about the "components" not being rated for 410. I don't like Soft tubing running 410a, 500psi behind flares and new thin aluminum coils because they're cheaper to make but manufactuers seem to think this is still dandy. Are the coils 30 years ago really not rated for the higher pressures? Liability aside I'd be very interested to see if anyone has proof that the coils are (and I repeat in reality) not able to withstand 410A. As mentioned yes, not rated for 410 but when it the age where it was unrealistic to rate a coil for that pressure why would they?

I do understand the concern over liability and there is something to be said if another company (which can be compared to some of the worry warts in this thread) came in and started running their mouth about how it's not a 410 coil. Is type m copper? Is it still silphos? Yeah ok, if the coil is soft solder I understand. The evaporator and the existing piping is the only issue.

It's recommended (by dupont anyways) that it have no more than a 5% mineral oil left in the system. Drilling the traps was a good idea. Definitely changing the suction accumulator. My "personal" opinion is that this thread is filled with a slight air of hysteria but we all know what they say about opinions . There is always the "absolute right" thing to do but frankly in some cases it's unrealistic in financial terms. You could have had a coil to match that air handler manufactured, repiped the entire run and done it that way but was that realistic? Is it still going to work in the fashion you described?

Time will tell.

[cy]

interesting thread....

[allstar08]

I agree, I have never been concerned with the integrity of the components. I have been concerned with the need of the accumulator. The indoor coil is in the basement and the outdoor unit is about 8-10ft above it. I don't think we even need it.

[alcomech]

I find this thread very interesting. Everyone seems to be incredibly worried about the "components" not being rated for 410. I don't like Soft tubing running 410a, 500psi behind flares and new thin aluminum coils because they're cheaper to make but manufactuers seem to think this is still dandy. Are the coils 30 years ago really not rated for the higher pressures? Liability aside I'd be very interested to see if anyone has proof that the coils are (and I repeat in reality) not able to withstand 410A. As mentioned yes, not rated for 410 but when it the age where it was unrealistic to rate a coil for that pressure why would they?

I do understand the concern over liability and there is something to be said if another company (which can be compared to some of the worry warts in this thread) came in and started running their mouth about how it's not a 410 coil. Is type m copper? Is it still silphos? Yeah ok, if the coil is soft solder I understand. The evaporator and the existing piping is the only issue.

It's recommended (by dupont anyways) that it have no more than a 5% mineral oil left in the system. Drilling the traps was a good idea. Definitely changing the suction accumulator. My "personal" opinion is that this thread is filled with a slight air of hysteria but we all know what they say about opinions . There is always the "absolute right" thing to do but frankly in some cases it's unrealistic in financial terms. You could have had a coil to match that air handler manufactured, repiped the entire run and done it that way but was that realistic? Is it still going to work in the fashion you described?

Time will tell.

So what are you trying to say about preventing a future failure. Its obvious that he has an issue. It is true that its any one's guess as to why he has experienced such a sudden failure, but unless he covers the basics- it is guaranteed that it will happen again..
As for myself I am not concerned with the fact that its a mismatched system, however if the components are not compatible they must then be replaced. It is not likely that his piping is type "M" copper and most likely it is at least type "L".

There are not too many people here blurting.... just stating the facts.
To down play this situation at hand and to not give a positive solution is not "realistic".

Trouble shooting is not part of the repair..........understand the symptoms and you will find a solution.

[Ohio 614]

Had a customer that did this. We gave them a quote to replace the evap coils but they went with a mom and pop operation that reused everything except the txv's. Well, 4 compressor replacements later I think it has finally run for 3 months straight. I noticed the suction line is always warm but I won't work on it because this customer is one of those that thinks " you touched it, its your problem now".

[Jimmyhat 597]

Salesman called me asked why i figured so much time to replace a compresser on a Desert Air unit. Says another shop beat us by 2k
"first I never saw it run, the customers maint. condemed it. Unit should be replaced. Every time I work there the Maintanence staff tells me how sharp they are and why am I here. Good luck to who got it" I figured 2 days for making it work right but go ahead cut the bid I'll slap a new Comp in and hit the button and walk away then wait for the customer wanting warranty after maint staff works on it.

[toocoolforschool]

Salesman called me asked why i figured so much time to replace a compresser on a Desert Air unit. Says another shop beat us by 2k
"first I never saw it run, the customers maint. condemed it. Unit should be replaced. Every time I work there the Maintanence staff tells me how sharp they are and why am I here. Good luck to who got it" I figured 2 days for making it work right but go ahead cut the bid I'll slap a new Comp in and hit the button and walk away then wait for the customer wanting warranty after maint staff works on it.

I think this is a new thread

[B1978]

I ran into this situation. Another contractor had the factory approve the huge slab coils from 22 to 410A. I went higher up and had it looked at and they said no. I quoted it the right way and lost out. Now its someone elses mess for life!
Didnt make the money from the job, but we also didnt risk the consequences of a lifetime of leaks.
Keep us updated if things start going bad?
You can also have a custom coil built once this one fails, etc.

[dunkman]

Had a customer that did this. We gave them a quote to replace the evap coils but they went with a mom and pop operation that reused everything except the txv's. Well, 4 compressor replacements later I think it has finally run for 3 months straight. I noticed the suction line is always warm but I won't work on it because this customer is one of those that thinks " you touched it, its your problem now".

Ha! Aren't they all???