30 ton split R-22 to 410a

[allstar08]

30 ton split system using existing 30 year old coils. All lines left in as well as accumulator. Txv's were replaced as well as liquid line solenoids. Suction line filter added and lines blown with nitrogen. How much left over oil in the system is acceptable? The coils had to stay I wish it could have been replaced. Holes were drilled in the traps and taps were added so oil could be drained and blown out with nitro. Thoughts and feelings? Unit is not fired off yet. I am thinking of removing accumulator, and flushing with a flush kit.

[AiResearch]

Pretty sure this is a huge mistake.

[Gibbo]

You need to take a step back and think about this.
UNDER NO CIRCUMSTANCES START THIS UNIT UP WITH R410A.
None of the components will be rated for R410A and are likely to fail using R410A.
If you want to change out R22 then you need to change to a compatible refrigerant USING SIMILAR PRESSURES such as R417A R422D depending on size of unit.

This is an accident waiting to happen.

[SouthTex]

Recently did a conversion on two 20 ton units as the condensers needed replaced. Warned the customer not to do it turns out we were right chasing refrigerant leaks on the indoor coil that were not there when the conversion was done. Big mess

[maxster]

both ends of the system was tested for R-22 now its going to see and feel 410A oil is the least of your problems,rebraze all the lines and do a 1000PSI nitro test maybe tonnage has to be effected with the higher pressures in what could be considered a low pressure original install

[ga-hvac-tech]

Seems to me a lot of similar refrigerants to R22 are available. I would be seriously worried about the system not handling the higher pressures.

Your prep sounds good... however a refrigerant that both operates at similar pressures and uses mineral oil would be my choice.

Let us know how this works out.

[allstar08]

I will say this job got dropped in my lap to wrap up and fire off. I have checked the majority of all the brazed joints and have a 450 psi test on it right now. I am just trying to make the best of a bad situation. I had heard there were some new schools of thought about actually leaving oil in the system. I am curious if anyone had done it. The job has to be fired of on Tuesday regardless of what I want, it is out of my hands.

[allstar08]

You need to take a step back and think about this.
UNDER NO CIRCUMSTANCES START THIS UNIT UP WITH R410A.
None of the components will be rated for R410A and are likely to fail using R410A.
If you want to change out R22 then you need to change to a compatible refrigerant USING SIMILAR PRESSURES such as R417A R422D depending on size of unit.

This is an accident waiting to happen.

condensing unit is installed and is 410. I think we have to use 410 t this point.

[allstar08]

Recently did a conversion on two 20 ton units as the condensers needed replaced. Warned the customer not to do it turns out we were right chasing refrigerant leaks on the indoor coil that were not there when the conversion was done. Big mess

have you had any acid problems? did you reuse the line sets as well as the coils? did you flush the indoor coils?

[ascj]

I will say this job got dropped in my lap to wrap up and fire off. I have checked the majority of all the brazed joints and have a 450 psi test on it right now. I am just trying to make the best of a bad situation. I had heard there were some new schools of thought about actually leaving oil in the system. I am curious if anyone had done it. The job has to be fired of on Tuesday regardless of what I want, it is out of my hands.

I haven't done a 22 to a 410a conversion using a unknown rated coil. But with that said, I have done conversions from a mineral to a POE refrigerant. From what you have said, I would skip the flush kit, but change the accumulator for good measure.

Why is there is an accumulator? And you only have one......is this a single lineset?

[allstar08]

I haven't done a 22 to a 410a conversion using a unknown rated coil. But with that said, I have done conversions from a mineral to a POE refrigerant. From what you have said, I would skip the flush kit, but change the accumulator for good measure.

Why is there is an accumulator? And you only have one......is this a single lineset?

original with the old system, I don't think it is needed with the new system. safety for low ambient operation I assume, the line set isn't very long.

[acwizard]

Pretty sure this is a huge mistake.

I tend to agree.The coil parameters are not even close between R-22 and 410. As far as accumulators goes, it needs to be resized for the change in refrigerant. Accumulators are inexpensive compared to compressors.These are the types of jobs that any good service company would love to chase. Lots of problems, and there is nothing like doing the job twice.

[ga-hvac-tech]

I tend to agree.The coil parameters are not even close between R-22 and 410. As far as accumulators goes, it needs to be resized for the change in refrigerant. Accumulators are inexpensive compared to compressors.These are the types of jobs that any good service company would love to chase. Lots of problems, and there is nothing like doing the job twice.

Seems I end up doing it the second time... after the first contractor has a phone number change...

I appreciate hacks (not referencing anyone)... they make me lots of $$$