Lennox 13HPX - Heat pump reversing valve stuck on heat, ~3 years old.

[pezzy84]

So went to flip my heat pump to cooling this past Sunday while cleaning - condo got a little past my high comfort temp (74F during cooling season) so I kicked it on cool and went about my Sunday cleaning ritual. ~7-8 mins go by and I'm wondering why is it getting hotter - go to the bathroom vent which is the easiest to reach to feel and feel heat blasting. Confirm I set it to cooling - yup, Nest app went from 20 mins to reach desired temp (76 to 74) to 1 hr 45 mins to desired temp and interior temp had jumped to 78. Shut system down, open windows (it was a nice 67 degree day) and figure try again in 15 mins. Try again same thing - stuck on heat. Have tried a couple times since (including heat mode) and still stuck on heat no matter if set on heat or cool. Before anyone asks the reason it was so warm with nice outdoor temps, I ran the self clean cycle on the oven which pushes out an amazing amount of heat in 3 hours.

Fortunately it is not the dead of summer and this problem is cropping up when A/C is not a necessity (mid 70's during day, 40's at night). On top of this the company who installed the full system was offering a pandemic special of buy 3 years get 2 years free preventative maintenance and you basically get a bumper to bumper (compressor to air handler?) no deductible warranty on the system for the entire 5 years so cost of this will be $0 no matter what the problem is.

Now hopefully they can get parts if needed. I'm annoyed that this ~3 year old heat pump is already giving problems considering it has PM 2x per year.

 

[brianl703]

It could be a bad connection to the reversing valve. Most default to "heat" if they do not get any 24VAC power.

 

[mk378]

Yes exactly. This is often an electrical problem. Check for 24 Vac at the reversing valve coil in cool mode.

Nest thermostats had a lot of trouble with the drive transistors burning out and causing exactly this situation. If your service contract doesn't cover the thermostat, you can bypass it by taking the thermostat off and hotwiring the red, yellow, orange and green wires all together. It should start up and make cold air.

 

[pezzy84]

It could be a bad connection to the reversing valve. Most default to "heat" if they do not get any 24VAC power.

I am really hoping it is something easy they can fix on the spot but we shall see tomorrow. Even if it is a problem with my Nest I will pay for whatever is on their truck because I can't sleep sweating my arse off.

 

[JimPghPA]

Nest thermostats had a lot of trouble with the drive "TRIAC" burning out and causing exactly this situation. If your service contract doesn't cover the thermostat, you can bypass it by taking the thermostat off and hotwiring the red, yellow, orange and green wires all together. It should start up and make cold air.

Fixed it for you.

 

[loneryder]

So went to flip my heat pump to cooling this past Sunday while cleaning - condo got a little past my high comfort temp (74F during cooling season) so I kicked it on cool and went about my Sunday cleaning ritual. ~7-8 mins go by and I'm wondering why is it getting hotter - go to the bathroom vent which is the easiest to reach to feel and feel heat blasting. Confirm I set it to cooling - yup, Nest app went from 20 mins to reach desired temp (76 to 74) to 1 hr 45 mins to desired temp and interior temp had jumped to 78. Shut system down, open windows (it was a nice 67 degree day) and figure try again in 15 mins. Try again same thing - stuck on heat. Have tried a couple times since (including heat mode) and still stuck on heat no matter if set on heat or cool. Before anyone asks the reason it was so warm with nice outdoor temps, I ran the self clean cycle on the oven which pushes out an amazing amount of heat in 3 hours.

Fortunately it is not the dead of summer and this problem is cropping up when A/C is not a necessity (mid 70's during day, 40's at night). On top of this the company who installed the full system was offering a pandemic special of buy 3 years get 2 years free preventative maintenance and you basically get a bumper to bumper (compressor to air handler?) no deductible warranty on the system for the entire 5 years so cost of this will be $0 no matter what the problem is.

Now hopefully they can get parts if needed. I'm annoyed that this ~3 year old heat pump is already giving problems considering it has PM 2x per year.

My heat pump did that in it’s first year. Guy came out, put it forced reversal and banged on t valve with a hammer. He said it’s not uncommon. Been working great for over three years.

 

[pezzy84]

Well it turned out to be my Nest thermostat (3rd gen) went bad - I would have to look to see when I bought it but it was probably 5.5 years old. I checked the thermostat battery and it was holding normal voltage so may have just been some internal fault - he attempted reseating all the wires and that still didn't work, then he manually wired two of the wires together and that kicked the air on.

I went ahead and replaced with same Nest thermostat, I know I know the first one died after 5.5 years why buy another considering how expensive they are ($199 after GA Power rebate) but I really like the interface and I have a whole Nest/Google Home ecosystem at home and did not feel like installing a whole new thermostat. Not to mention it took about 5 minutes to replace as it is just pop the old wiring base off (two screws), plug the new wires in and pop the new thermostat face on and all we well in the world.

Glad it wasn't anything wrong with the system so it didn't need to be opened up.

 

[RhondaHonda]

Some meth-heads stole my buddy’s outdoor unit once and it somehow made the indoor unit run on aux heat so when he got home that night it was super hot in the house. Glad you got yours figured out.

 

[mk378]

The problem is in the base part of the thermostat. The top part will be OK. Google sells the base separately, though they are out of stock.

Nest Learning Thermostat 3rd Generation base - Google Store

Use this as a replacement base for Nest Learning Thermostat 3rd generation in the United States and Canada. Requires a Nest Learning Thermostat 3rd generation.

store.google.com

 

[brianl703]

Some meth-heads stole my buddy’s outdoor unit once and it somehow made the indoor unit run on aux heat so when he got home that night it was super hot in the house. Glad you got yours figured out.

There's a wire from the outdoor unit that turns on aux heat when it's in defrost. If this was touching the Y wire then it would do that. Those meth-heads should have carefully taped up all the wires so they weren't touching after they stole the unit.

 

[pezzy84]

The problem is in the base part of the thermostat. The top part will be OK. Google sells the base separately, though they are out of stock.

Nest Learning Thermostat 3rd Generation base - Google Store

Use this as a replacement base for Nest Learning Thermostat 3rd generation in the United States and Canada. Requires a Nest Learning Thermostat 3rd generation.

store.google.com

This is good to know - might keep my eyes peeled to see if the base goes back in stock. Have a friend who would want my old one if it will work with a new base. Thanks for the heads up!

 

[billt460]

I have a heat pump...... And I never use it on "HEAT" because of experiencing similar issues, turning it back and forth from "HEAT" to "COOL" every season. My neighbors always seem to have similar issues with their heap pumps.

I basically run mine as an air conditioner only. And as a result, I've never experienced a problem. I do have the luxury of living where it rarely gets that cold. And almost never gets below freezing. I have a gas fireplace, along with a couple of electric space heaters, that easily take the early morning chill out of the house. Once the Sun rises, nothing is needed to heat the house.

My house actually warms up faster without it. Every heat pump I've had or experienced, wastes a LOT of electricity, and only blows luke warm air out of the registers. I've never seen one that really heats the air effectively.

 

[brianl703]

I have a heat pump...... And I never use it on "HEAT" because of experiencing similar issues, turning it back and forth from "HEAT" to "COOL" every season. My neighbors always seem to have similar issues with their heap pumps.

I basically run mine as an air conditioner only. And as a result, I've never experienced a problem.

Most heat pumps energize the reversing valve in "COOL" (except for Rheem and RUUD units and possibly some others) so unless yours is one of those, you are accomplishing exactly nothing by not running it in "HEAT".

And if it's above freezing and your heatpump only blows out lukewarm air, I'd suggest that there is something wrong with it.

 

[billt460]

Most heat pumps energize the reversing valve in "COOL" (except for Rheem and RUUD units and possibly some others) so unless yours is one of those, you are accomplishing exactly nothing by not running it in "HEAT".

And if it's above freezing and your heatpump only blows out lukewarm air, I'd suggest that there is something wrong with it.

It doesn't accomplish much when it IS run in "HEAT". Which is why I don't bother using it. And I've never seen a heat pump that really puts out hot air. When you get down to it, they're nothing more than an air conditioner that runs backwards.

 

[brianl703]

It doesn't accomplish much when it IS run in "HEAT". Which is why I don't bother using it. And I've never seen a heat pump that really puts out hot air. When you get down to it, they're nothing more than an air conditioner that runs backwards.

I have no idea what's wrong with your heat pump, but I heat my house with a heat pump. In a climate that gets way colder than where you are. And I have the aux heat disabled, and I've never needed to turn it on.

And, by the way, a typical heat pump is at least 200% more efficient than a space heater at any outdoor temp above about 10F. At 30F it's more like 300% more efficient.

No, they don't blow air as hot as a gas furnace, but I've had a house with a gas furnace and getting blasted with hot air with it running isn't exactly my idea of comfort. Heat pump provides way more even temperatures.

 

[billt460]

I have no idea what's wrong with your heat pump, but I heat my house with a heat pump. In a climate that gets way colder than where you are. And I have the aux heat disabled, and I've never needed to turn it on.

And, by the way, a typical heat pump is at least 200% more efficient than a space heater at any outdoor temp above about 10F. At 30F it's more like 300% more efficient.

No, they don't blow air as hot as a gas furnace, but I've had a house with a gas furnace and getting blasted with hot air with it running isn't exactly my idea of comfort. Heat pump provides way more even temperatures.

I've found them to be extremely non efficient in relationship to the amount of electricity they use. Gas is far more efficient, cheaper, and heats much faster. If gas is available I can't understand why anyone would choose a heat pump over it.

They're a waste of money in comparison. They're also problematic and more expensive when compared to a straight A/C unit.

As I said, I'm glad I live in a climate where I don't really "need" one. They're put on all the homes out here, because not a lot of homes have gas available.

 

[brianl703]

I've found them to be extremely non efficient in relationship to the amount of electricity they use. Gas is far more efficient, cheaper, and heats much faster. If gas is available I can't understand why anyone would choose a heat pump over it.

They're a waste of money in comparison. They're also problematic and more expensive when compared to a straight A/C unit.

As I said, I'm glad I live in a climate where I don't really "need" one. They're put on all the homes out here, because not a lot of homes have gas available.

They are more efficient than resistance heating, which is practically the only alternative if you're using electricity for heating.

And if gas isn't available your other options (besides electricity) are propane and oil, and a heat pump is usually cheaper than both of those.

The additional cost of a heat pump over a straight-cool AC unit is less than $1000--a reversing valve, a defrost control board, and a heat pump capable thermostat are the main differences.

In the places I've lived (three) which had a heat pump--never had a problem with it. Well, except the one day I woke up to find my house cold and the 50 amp breaker for the air handler tripped. Reset it and the unit worked fine.

Did a little more investigation and found that the installer had swapped the feeds for the 50 and 60 amp breakers in the air handler, so what should have been on the 60 amp breaker was on the 50 and vice-versa.

I swapped the feeds around and it's been fine since.

Attention to detail is important.

 

[pezzy84]

I have a heat pump...... And I never use it on "HEAT" because of experiencing similar issues, turning it back and forth from "HEAT" to "COOL" every season. My neighbors always seem to have similar issues with their heap pumps.

I basically run mine as an air conditioner only. And as a result, I've never experienced a problem. I do have the luxury of living where it rarely gets that cold. And almost never gets below freezing. I have a gas fireplace, along with a couple of electric space heaters, that easily take the early morning chill out of the house. Once the Sun rises, nothing is needed to heat the house.

My house actually warms up faster without it. Every heat pump I've had or experienced, wastes a LOT of electricity, and only blows luke warm air out of the registers. I've never seen one that really heats the air effectively.

It turns out it wasn't anything with the unit - it was something with my 6 year old Nest thermostat that was causing the issue - someone above mentioned base plate failure and a new base plate may fix it. Ended up buying a new thermostat and everything is working fine now. Honestly my Lennox is now a little over 4 years old and has never had an issue except for a noisy startup that is apparently just common to the model - my service tech recommended a hard start kit so had that done but it really didn't do anything for the rowdy startup so I just live with it at this point.

Not sure where you are getting info that heat pumps waste a lot of electricity - they are by far the most efficient way to heat in climates that can support it which is about the lower 2/3 of the United States, even now with the high $$ variable speed units they can still heat in temps below the single speed units. Now if you are allowing or forcing the backup (Emergency) heat to kick in yeah that will blow your electric bill to the moon, even dipping down in the teens here in Atlanta I don't ever recall seeing my Nest calling for the backup heat strips to kick on. IDK your system though so just passing on what I know - your climate is prime for a heat pump though.

 

[Rand]

The only gas use in my house is the furnace. so I have to get socked with the monthly 44.83 service connection charge. I use 0 gas 6-7 months of the year.

small house I bet a heat pump would be cheaper after you factor in I use around 37 mcf per year and could ditch the 45$ monthly charge.
Natural gas is very cost effective esp. when you lock in a decent rate (currently $3.31)

so the natural gas supply charge for the year is around ~~122$ there is additional distro charge of around 70cents per mcf. or 26$ based on last years use.
so I pay 148 in usage based charges + tax + utility recovery type fees. and 540$ in connection charge + taxes + more fees.

So even if a heat pump cost 3x as much to provide as much heating as 37mcf of natural gas.. I'd be ahead.

For those with larger houses, gas water heaters and stoves etc.. the numbers are different.
Although I bet most are paying more than the supply charge of 3.31.. the normal dominion rate last winter was 6-7$
Propane is crazy high to heat with.. iirc 6-10x the cost of natural gas.

 

[ragtoplvr]

After several instances of my nest thermostat turning off the heat while it thougt I was not home it went in the trash.

My new dumb programable thermostat has been working just fine.

Rod