Sticking or Jammed Air Conditioner Thermostatic Expansion Valve
How to Fix an A/C or Heat Pump TEV that's not working, won't cool, warm air flow
TEV STICKING REPAIR - CONTENTS: repair of a jammed thermostatic expansion valve at new air conditioner or heat pump installations. Data about & contact information for KeepRite air conditioners & Tempstar air conditioners & heat pumps
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Sticking or jammed thermostatic expansion valves:
In addition to debris, dirt, or icing problems that occur in TEVs or thermostatic expansion valves, sometimes the thermostatic expansion valve on brand new air conditioners may need an extra jolt to get it working, as we explain here.
Sticking Air Conditioner or Heat Pump Thermostatic Expansion Valves at New Installation
At TEV INSTALL & REPAIR where we list various troubles with thermostatic expansion valves and suggest diagnostic and repair procedures we noted the following:
[Click to enlarge any image]
Sticking TEV valves:The TEV and also AEVs depend on a little oil or oil mist flowing along with refrigerant to lubricate the interior of the valve.
Occasionally debris in the refigerant system can cause the TEV to jam, chatter, or fail to perform properly.
But we suspect that a more common cause of TEV valve sticking is the freezing of a droplet of water at the needle valve, holding it stuck. The valve stops working properly.
But as we learned from Ontario reader E.T. and her HVACR installation and service company, TEVs may be "sticky" right out of the box from the manufacturer. At left: a KeepRite™ air conditioner compressor / condensing unit, newly installed.
The installer used a simple "overcharge" procedure to free the TEV as we describe in this reader report.
Reader Question: new KeepRite® air conditioner not working well: does not cool the house
I placed a comment on the InspectApedia website last night about my new air conditioner not working well. Here are the photos you asked for. Our house is 980 square feet with a finished basement. I have closed all the vents in the basement.
We live in Ontario and are having fluctuating temperatures. Today it is 72F outside with an expected high of 85. I turned the air conditioner on yesterday when the outside temp was 65F and the temp inside my house was 78 because it had been a hot day and the air conditioner was not able to bring the temperature down.
I set the thermostat for 72F. It took 5.5 hours to bring the temp down to 76F, which is when we went to bed. Thorough the night it managed to bring the temp down to 72. In the morning I turned the thermostat up to 73 and the air conditioner has not stopped running, even momentarily, since I got up this morning. The couple of times I woke through the night it was running as well (I have a young baby).
I was not given a manual, only an invoice for the unit and the work done. It was installed 4 weeks ago. We had the ducts cleaned 3 years ago and they do need cleaning again - I have an appointment booked for Friday. If you would like to see the emails that were exchanged with the installer I can forward them to you.
Thank you very much for getting back to me so quickly. I appreciate that I am able to ask questions this way. - E.T. 7/21/2014
Reply: why doesn't the installer fix their installation SNAFU?
I see in your photos a newly installed air conditioning system that by your description certainly is not cooling.
Your additional photo (left) shows that a refrigerant-drier was installed, though I can't tell from the image if it's in the right direction or not. The flow direction is marked plainly on the canister label.
Something as simple as failure to adequately clean (pull a vacuum) and filter the refrigerant system could cause the system not to cool even if the compressor and air handler themselves seem to be working.
It's usually easy to diagnose a new system by checking refrigerant charge, pressures, temperatures, and current draw. Why didn't the installing company return to fix it?
Enlarging your third photograph of the data tag on the KeepRite condenser / compressor unit (shown at below left) gives us more information about this unit.
The Product model number begins with N4A318K ... which is the same as found on Tempstar® R-410A refrigerant air conditioning compressor / condenser units in the N4A3 series. These units use a Copeland® compressor and are factory-charged with R-410A refrigerant.
It's possible that your KeepRite® air conditioner is using the same equipment components, re-branded with the KeepRite® name.
Decoding the Model Data on a KeepRite® Air Conditioning Compressor / Condenser Unit
Since you were given no information whatsoever about your equipment, not even an installation/operation manual we're providing some data here.
Decoding the KeepRite® product number, N4A318KC100, based on TempStar's data (cited below)
N = "Tempstar Entry" brand ( KeepRite®-branded equipment, according to the manufacturer cited below, uses a product nomenclature beginning with a K, such as KMHA050 H2- HT4A-A)
4 = Refrigerant is R-410A
A = Air Conditioner (H would indicate a heat pump)
3 = SEER = 13
18 = 18,000 BTUH or 1 1/2 tons of cooling capacity
K = Voltage code 208/230V - 1- 60 (single phase 60 cycle)
Reader Follow-up: sticking thermostatic expansion valve on new AC installations
I had the oven on for approximately 20 minutes at lunch time. The inside temp has risen and is staying at 76F although it is 72F outside and I have the thermostat set for 73. The air conditioner still has not stopped running. We have two dogs, our ducts do need cleaning as I mentioned before. But we did have it done 3 years ago.
Can this affect the air conditioner functioning to this extent? The unit is obviously working because it did finally bring the temp down through the night and maintained it this morning - but why it's struggling so hard is unclear to me.
The A/C installer did identify the problem and he came back to fix it.
I'm relaying the information that I recall from what he told us so it may not be perfectly clear, but he said the diaphragm on the TY [TEV or Thermostatic Expansion Valve- Editor] valve (??i think) was sticking on the new installs and causing it to not be seated properly.
When he contacted the manufacturer they advised to overcharge the system and force it open further, which would cause it to then close properly and seat the valve.
I hope I got the information right, as this seems to be an innate problem with these units and I would hope that this information could be useful to someone else down the road.
I also want to say that I found this website just through a Google search when we were having the issues with the A/C and I was feeling desperate that something had to be wrong and was being told that it probably wasn't. You provide an invaluable service allowing yourself to be contacted with questions and providing service to others the way you do. It's a very generous thing to do and do and I, for one, am grateful that you took the time to respond. Thank you very much!
I was very glad that our install person kept coming back and looking into the issue and finally got it fixed.
Reply: Expansion Valve SNAFUs
Indeed even a small amount of dirt or debris in a new refrigeration system can foul up the thermostatic expansion valve causing it to fail to operate properly. If the installer is making an error in cleanliness during initial installation, or if s/he forgets to install the proper refrigerant filter/dryer on the refrigerant lines, or if the refrigerant charge is incorrect the TEV may jam or fail to open and close properly. Of course it's true that the TEV itself could be defective.
The result is failure to release refrigerant at the proper rate into the cooling coil in the air handler. In turn that would allow the air handler to run without adequately cooling the building.
Reader Follow-up: using a refrigerant "overcharge" to clear a stuck TEV
Our air conditioner installer installed an identical unit to ours (a Keeprite) at another customer's house this week and was having the same issues as us. He contacted the manufacturer and was told that there is an issue in that model with a valve not closing properly on installation. The unit needs to be overcharged which forces the valve open so that it snaps shut. He came tonight to do just that and it seems to be cooling.
I will be able to send more information about the specific valve etc when my husband gets home as he understands it better than I do, but I wanted to send an update to let you know that the problem has been found and in a case anyone writes in with a similar issue.
Reply: watch out for refrigerant overcharging
Watch out: The overcharge needs to be removed lest the compressor motor be destroyed.
Watch out: warranty coverage: You should register your product to assure proper warranty protection, and you should obtain the owners or installation manual for your air conditioner from the installer or if that contractor cannot help you, use the contact information we provide above to contact the company. Our search of the KeepRite websites we found did not provide links to manuals or installation guides for equipment matching your product number.
You had told me that the overcharge needs to be removed, so I checked and he did remove it at the time.
Company Contact Information for KeepRit®e & TempStar® air conditioning & heat pump product types & series
KeepRite® Heating & Cooling Products, Website: http://www.keeprite.com/ (At this website the company does not provide an address, company information, nor contact information). The KeepRite website does cite HVAC contractors in West Chester OH, USA, and Toronto, Ontario, Canada. Other contact information for KeepRite® Refrigeration is at http://k-rp.com/node/149, Factory telephone: 1-800-463-9517 Email for Warranty claims: warranty@k-r0pcom Customer Support Email: firstname.lastname@example.org
The KeepRite® compressor/condenser unit features a two-stage scroll-type compressor motor and the company cites a 10-year warranty.
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 "Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]
 Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects" section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and home inspection educator.
 Thanks to Jon Bolton, an ASHI, FABI, and otherwise certified Florida home inspector who provided photos of failing Goodman gray flex duct in a hot attic.
 Thanks to Scott at SJM Inspect for suggesting this EPA document and for technical editing remarks regarding our air conditioning website,
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"Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]