Heat pump not heating


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Old 09-23-23, 12:38 PM
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Heat pump not heating

Had a Lennox HP and heater [emergency heat] installed 5-7 years ago [$10+k] -- Had a $600+ system check [a few hours] done a couple of weeks ago and nothing out of the ordinary was mentioned [system fine, I guess].

A couple of days later noticed the HP was blowing cool air so had someone come look at it. This technician believes it is the TXV [in the heat pump] and proceeded to demonstrate with ice and comparing with that exterior TXV and an interior TXV. Replacing it would be about $4k because of the labor involved at accessing the valve.

My questions are:

Does this seem right? Can I test it [or other possibilities]?
 
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Old 09-23-23, 01:05 PM
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Replacing it would be about $4k because of the labor involved at accessing the valve.
tpring - Where is the TXV located that makes it so laborious to replace a ~$100-$200 valve? It shouldn't cost more than $400-$500 at the most to replace the TXV. A $600+ system check!

Maybe you misunderstood the tech?
 

Last edited by Kooter; 09-23-23 at 02:56 PM.
  #3  
Old 09-23-23, 02:43 PM
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A $600 system inspection.
If that is the installer or installing company.... that is not acceptable.

$200 for annual "inspection" would be at the upper limit.

There should be only one TXV valve. It's inside in the air handler.
There is a reversing valve out in the condenser.

I'd lean towards a reversing valve solenoid coil defective before a defective valve.
You can easily check the valve solenoid.
In cooling mode set the thermostat to 80
Turn the thermostat off.
Wait 10 minutes.
Using someones help.... have them turn the stat to cool while listening at the condenser.
Listen just above the cooling fan. You should hear a fairly loud click.

You're listening for a click from the solenoid.
Since the stat was set high... the contactor won't start.
 
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Old 09-23-23, 04:08 PM
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Thanks for the replies. I got this info second-hand [from wife] so still piecing things together.

$600 was actually included a check of the water heater, heater & heat pump, but still quite pricey [as is everything on the west coast].

The device that is believed to be faulty is outside so it sounds like the reversing valve in the condenser is what the tech was talking about. He used ice to check whether the TXV and reversing valve were working and the device that is outside is the one that is faulty [according to the tech].

His explanation for the $4k bill had something to do with some soldered connections and taking apart the condenser which all would take several hours.

Thanks for the process to test -- Going to have to do a quick study on heat pumps. Do you think the solenoid coil [or condenser] is a job that a low-voltage electrician could tackle?
 
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Old 09-23-23, 06:00 PM
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The coil is a DIY replacement.
The valve is a major job. Definitely not a DIY job.
The reversing gets power only in cooling mode. No power on heat.

In the link is an interesting way to check Lennox reversing valves.
You may have to pull your fan out to get to the valve.
Testing Lennox rev valve - video
 
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Old 09-24-23, 06:27 PM
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What is the model number of this Lennox heat pump?

I see the XP17 has a TXV outside...


 
  #7  
Old 09-24-23, 08:56 PM
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It is model xp14 and yes it does have a TXV on the outdoor unit and as far as I know [at this point] it is responsible for heating control and, I believe, one indoors that controls cooling. And the HVAC tech "determined" that it is defective and is preventing my HP from heating the house.

Also found that the $4k cost to replace includes various items such as evacuating and recharging refrigerant, nitrogen check, sealing leaks, brazing fittings and about $600 for the TXV.

My goal is to try and verify if the TXV needs to be replaced or if the tech was just guessing. At this point, I might even consider replacing it with an A/C unit. Just not seeing any benefits in the HP.

 

Last edited by tpring; 09-24-23 at 10:27 PM.
 

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