Rheem 14 ton 13 SEER system keeps freezing


  #1  
Old 05-19-10, 07:14 PM
D
Member
Thread Starter
Join Date: May 2010
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
Rheem 14 ton 13 SEER system keeps freezing

I have a Rheem system, 13PJA48A01 condenser/heat pump unit, RHLA-HM4821JA indoor air handler that was installed when our house was built just over two years ago.

There is an extensive service history on the unit, the refgrigerant line was installed so that it was bent almost 90 degrees at the point where it exits to the outside. A faulty thermostatic expansion valve took out the original compressor in late '08, and this past winter the sensor bulb in the outside unit had to be moved to resolve an issue with a knocking sound when the unit was shutting down.

The company who installed it (we didn't pick them, our builder did all that) are a bunch of hacks and in my non-expert opinion seem to cut a lot of corners and don't really care too much about the quality of the workmanship they do. It's RGP, Inc. out of Hiram, GA in case someone in the area needs to know who not to hire.

Recently, the unit is starting to freeze when it runs in Cool mode for a while. Not an issue with clogged filters, that's one of my regular maintenance points. I am concerned that when the tech relocated the sensor bulb this past winter, which was a manufacturer's recommendation to solve the knocking noise issue, he re-used the old insulation and just attached it with a couple of cable ties. It looks tacky to me, but I am not an HVAC tech so I had to assume this guy knew what he was doing.

Now my question is, could this be the cause of the problems I'm experiencing? I know that a low system charge of refrigerant would cause this problem, and I have not had a tech out to check system pressure but I doubt that would be the case here. I'm thinking either defective thermostatic expansion valve (that would make the second one) or the insulation job on the sensor bulb. Possibly also how the bulb itself is actually attached/aligned on the refrigerant line.

I took some pics, and am hoping someone with experience could tell me if it looks like it's acceptable of the possible cause of the freezing issue.





 

Last edited by DBLarsson; 05-19-10 at 07:20 PM. Reason: Fixed image links
  #2  
Old 05-20-10, 02:24 PM
E
Member
Join Date: Feb 2010
Location: usa
Posts: 616
Received 0 Votes on 0 Posts
does it blow cold air while its running? maybe your motor doesnt work? the txv valve on the outside unit is used for heat. but it looks fine and is not the reason you are icing up. it does seem like you are low on freon, probably a leak at the indoor txv in the coil but who knows. i hope the builder is paying and if he isnt you should make him.
 
  #3  
Old 05-20-10, 08:12 PM
D
Member
Thread Starter
Join Date: May 2010
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
It does blow cold air, but if I set the thermostat to lower than a couple of degrees below current temperature, to where it will run for, say, more than 20 minutes, condensation starts to form on the refrigerant and suction line by the inside unit, and soon thereafter it ices up and no air comes out the ducts. I just turn it of and switch the fan from auto to on for a while to thaw it out and its usually good to go again, as long as I don't make it run for too long...

So am I misunderstanding the role the TXV plays, does it only control the flow of refrigerant when operating the system in heat pump more? I was under the impression that it controls the flow of refrigerant in either direction, and the only difference when the system is in heat pump mode is that refrigerant flows through the system in the opposite direction, but I am by no means knowledgeable about these kind of things.

I guess if that is the case, the only remaining issues that could cause freezing would be malfunctioning auto-defrost control (which is rare I hear?) or low refrigerant charge due to a leak in the system. I will have someone (NOT Residential Gas Piping!) out to check that for me tomorrow hopefully, but with a system that's less than two and a half years old, the only cause of a leak I could imagine would be a botched install job. Which, given what I have seen these idiots do, wouldn't be unlikely.

The builder won't help me, they are as incompetent and unscrupulous as the HVAC subcontractor they hired. It is Hunter Homes in Madison county, Alabama in case anyone is interested, but I would quickly go off-topic for this part of the forum if I started ranting about all the problems they have given us.

The good news is that the manufacturer, Rheem, called me today after I contacted them and explained the situation, and their regional technical trainer will be in touch with me after he follows up with RGP to try to resolve the issue. I'm hoping that they will realize that letting incompetent "technicians" install and service their equipment will cost them a fortune in warranty replacement parts (they've already had to foot the bill for a TXV and a compressor, and if the system runs low on refrigerant for much longer they could end up having to give me yet another compressor).

Is there anything in particular I should look for at the inside air handler? Anything I could take pictures of for someone with experience to be able to help me assess this? I greatly appreciate all the help I can get here.
 
  #4  
Old 05-26-10, 08:30 PM
D
Member
Thread Starter
Join Date: May 2010
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
An update on this: Finally had one of Rheem's independent certified contractors out to look at the system. It was indeed low on refrigerant, almost 4 lbs low on a system that should normally have about 10 lbs. No obvious signs of a leak, but there is a good chance that when RGP last messed with it they either didn't charge it the right way, i.e. by measuring superheat, and rather just went by the crappy chart on the sticker on the outside unit. Oh, and see these pictures, with the feeler bulb for the TXV mounted on the compressor discharge line...



Obviously the tech moved it to the suction line, and used a more, ahem, professional approach to insulating it.

Residential Gas Piping were contacted by Rheem's regional rep, and fed him a bunch of lies, basically saying that the system is working fine. They have not even been out here since December of last year. Fortunately, I have pretty good documentation of the professional malpractice RGP has engaged in, so I am hoping to be able to recover what I've had to spend so far on repairs. That R-22 doesn't come cheap nowadays.
 
  #5  
Old 06-06-10, 09:26 AM
M
Member
Join Date: Jun 2010
Location: USA
Posts: 1
Received 0 Votes on 0 Posts
Undercharge

How long is your copper lineset from the inside unit to the outside unit? This can make a difference in the charge required. I had one last week where the charge was also over 4 lbs low. The evaporator was frozen solid.

I used the subcool method to charge and got the system to 15.5 degrees subcooled with normal operating pressures of 80 low side and 195 high side at 85 degrees ambient.

I also could find no leaks. Keep us posted on how your system does.

Superheat will let you know that the txv is functioning properly but is not used for charging a heat pump.
 
  #6  
Old 06-06-10, 11:59 AM
E
Member
Join Date: Feb 2010
Location: usa
Posts: 616
Received 0 Votes on 0 Posts
did i read this correctly, did you say a 14 ton unit for your house? what is it, a mansion? the unit itself must be gigantic. and if it is then money is no issue for you, just replace it all. not to mention 4 pounds low, most convetnional 3 or 4 ton units only hold 4 pounds of freon.
 
  #7  
Old 06-07-10, 02:20 PM
D
Member
Thread Starter
Join Date: May 2010
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
Originally Posted by ender2272 View Post
did i read this correctly, did you say a 14 ton unit for your house? what is it, a mansion?
Oops, I blame butterfingers. It's a 4 ton unit, nothing else. The house is a two-story single family dwelling, approximately 2300 sq ft.

Originally Posted by mdswinterpark
How long is your copper lineset from the inside unit to the outside unit? This can make a difference in the charge required. I had one last week where the charge was also over 4 lbs low. The evaporator was frozen solid.
I am not sure about the exact length of the lineset, but we estimated it to around 20 ft. It runs inside the wall, between the floor truss and up into the HVAC closet on the second floor, so it doesn't have to run all the way up to the attic or anything. The tech who charged the unit said he believed the system would hold a total of about 10 lbs of R-22. Since I don't know exactly how long the lineset is, it's not very meaningful to speculate in this I suppose.

He charged it for 10 degrees of subcooling at 90 degrees ambient temperature, and verified this to be the appropriate charge by reading 18 degrees of superheat, down from over 40 degrees when he first arrived. Does that seem about right?

Tech will be out to leak check on Thursday, it will be interesting to see what they will find.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: