overcharging 410A heatpump

[thorton]

Originally posted by airworx
subcooling is used to check the charge on any expansion valve system. type of refrigerant has nothing to due with it. subcooling tells you how much refrigerant is in the system. if charge is low subcooling will be low if charge is high subcooling will be high.

Hi Airworx: Would you mind explaining to me how tech's check the subcooling.

Thanx--Thorton

[dpatty]

Originally posted by thorton
Hi Airworx: Would you mind explaining to me how tech's check the subcooling.

Thanx--Thorton [/B]

Per site rules we are not allowed to give instruction on how to do this, sorry

[beenthere]

Originally posted by dpatty

Originally posted by thorton
Hi Airworx: Would you mind explaining to me how tech's check the subcooling.

Thanx--Thorton

Per site rules we are not allowed to give instruction on how to do this, sorry [/B]

All he has to do is a search, and he'll find the for your interest, and a whole bunch of other post that tells anybody how to do it.

[dpatty]

Yea thats true, That does seem to contradict the site rules doesn't it. Maybe Boss needs to look into that.

[thorton]

beenthere & dpatty--I'm not looking to try and fix the heat pump myself. What I'm trying to do is become more informed when my equipment is being serviced. You two may be very good refridgeration mechanics, nevertheless, there are some in the business that are not that great. This leaves consumers at the mercy of these not great contractors. So I try to become informed about things that I'm buying or having serviced. Hope you understand.

Thorton

[dpatty]

When a unit is serviced the tech should hook up some kind of temp probe to the lines comming from the unit, Thats how they get superheat and subcooling numbers. If they are not checking these temps then they are not doing there job. If the tech just wraps his hands on the lines then you know your not dealing with a good company and your unit will suffer.

Most companies that cannot figure out whats wrong with a unit do not even have the tools to do this.

[Edited by dpatty on 07-16-2005 at 02:05 PM]

[hvac r us 2]

Thorton you have the right approach, as a homeowner myself I understand where you are coming from.

TXV’s can go bad, a lot more TXV’s have failed due to foreign material, overheating, or just plan old miss-diagnosed in my opinion.

Non-condensable can shut a TXV down right now; of course changing the TXV will correct the problem after the system has been cleaned up properly. But it probably would not have failed in the first place if a proper evacuation and start was performed during installation.

Puron can be “topped off” so to speak. It is a 50/50 blend with an even leak rate. But the bigger question is why should it have to be topped off? Don’t let anybody kid you when they say, “better to be a little low” that is just as damaging to the compressor.

When you’re low on refrigerant there is not enough suction gas to properly cool down the compressor.

A little high, a little low…here’s a novel idea, how about being right on?

Sorry, you caught me monologing…sore subject with me (refrigerant charging)

Anyhow, checking sub cooling would be to complicated to explain to somebody with no refrigeration knowledge. But it would not hurt to ask you’re dealer how they determined if the charge is right, guys that respond with “the pressures looked good” are scary.

In your case the answer would be they charged by sub cooling, probably for that unit in the range of 12-14 degree’s of sub cooling.

Another thing to look for, did they change the liquid line drier? If the answer is no I would worry about their workmanship…insist on a new drier since they have been into the system.

Good luck, there are lots of great HVAC guys out there. Protect yourself by educating yourself on the subject.


One thing I did not see mention was the serial number? There were some units that got out with contaminated accumulators. I believe without looking most was in the 04 range.

There is a policy for that which gives the dealer the ability to change out the unit and labor.

Something you might want to look into.

[beenthere]

I'm not concerned if your trying to check the system yourself or not.
I just pointed out that the information is all over this board.

If you want, you can do the search, and print it out and study it.

Heck, it might even help a tech learn something, if you show it to them.

[thorton]

Originally posted by hvac r us 2
Thorton you have the right approach, as a homeowner myself I understand where you are coming from.

TXV’s can go bad, a lot more TXV’s have failed due to foreign material, overheating, or just plan old miss-diagnosed in my opinion.

Non-condensable can shut a TXV down right now; of course changing the TXV will correct the problem after the system has been cleaned up properly. But it probably would not have failed in the first place if a proper evacuation and start was performed during installation.

Puron can be “topped off” so to speak. It is a 50/50 blend with an even leak rate. But the bigger question is why should it have to be topped off? Don’t let anybody kid you when they say, “better to be a little low” that is just as damaging to the compressor.

When you’re low on refrigerant there is not enough suction gas to properly cool down the compressor.

A little high, a little low…here’s a novel idea, how about being right on?

Sorry, you caught me monologing…sore subject with me (refrigerant charging)

Anyhow, checking sub cooling would be to complicated to explain to somebody with no refrigeration knowledge. But it would not hurt to ask you’re dealer how they determined if the charge is right, guys that respond with “the pressures looked good” are scary.

In your case the answer would be they charged by sub cooling, probably for that unit in the range of 12-14 degree’s of sub cooling.

Another thing to look for, did they change the liquid line drier? If the answer is no I would worry about their workmanship…insist on a new drier since they have been into the system.

Good luck, there are lots of great HVAC guys out there. Protect yourself by educating yourself on the subject.


One thing I did not see mention was the serial number? There were some units that got out with contaminated accumulators. I believe without looking most was in the 04 range.

There is a policy for that which gives the dealer the ability to change out the unit and labor.

Something you might want to look into.

Hvac R us 2: Thanks for the support. I was hoping that some people would understand where I was coming from. Yes, they changed the liquid line filter/dryer when they opened up the system. I just want you to know that it was the fan coil that they changed the TXV in. The serial # is 2001A62237, model # is FV4ALK003

Thanks Thorton

[hvac r us 2]

I was actually looking for the outdoor unit serial number, probably a 01 since the air handler is. That would put it out of range...

[thorton]

Originally posted by hvac r us 2
I was actually looking for the outdoor unit serial number, probably a 01 since the air handler is. That would put it out of range...

Hi hvac r us 2--Yes it looks like the heat pump was made in 2001, serial # is 2001A62237. Thanks for your info anyways.

Thorton