Any Home HVAC guys out there?

I have a question.

Our Heat Pump (electric) will not shut off some times.
When it does this, the AUX light comes on also.
My understanding is that the Thermostat is the only thing that can command the AUX Heat to come on. Is this correct? And would replacing the Thermostat be worth trying?

Here are the things I tried:

1. Turning the heat on, then lower the Temp. on the thermostat to BELOW the current room temperature. When I do this, it stays ON and running. The heat and blower never turns off.
And the temperature of the house continues to go up. Also, the AUX comes on and flashes.

2. Turn the Thermostat Off.
If I do this, everything goes off.

This has happened 2x now. And each time, it was when the temperature outside dropped below freezing. Once last year, and then just now this year.

Any ideas, I know very little about HVAC.
I don’t care to call in professional help, but I also know that it can be expensive.
Our current system was installed in 1997, and I afraid most companies will just want to replace the unit.

2020 has been a bad year for us all. I’d like to wait until our finances are a bit better before buy a whole, unless it is absolutely necessary.

 

Try to disconnect the thermostat from the heater. All it does is basically open a circuit on the heater when it “calls for heat”.

you can use a paper clip to temporarily jump the pins to simulate the heat call. If I recall correctly it’s typically the red and white wires but check the diagram on your heater to be sure.

 

Re-reading your post it appears that your thermostat is faulty which luckily is not a very expensive replacement unless you go top of the line LCD smart tech

 

I should also admit, I’m not a professional, just know enough to be dangerous

 

I would replace the thermostat, there fairly inexpensive, especially if it's not shutting the unit off when you set it below the temp in the room for heat. As for the AUX flashing, that's for your 1st stage heat(compressor/reversing valve), your 2nd stage heat would be emergency heat(heat strips)

 

Thanks for the advice guys.

Yeah, I’m going to try a New Thermostat.
I do plan on installing a Smart Thermostat.
Either the Ecobee or Nest E.

I would like to be able to check the temperature in the house while I am away during the day. It’s not at all pleasant to come home to house that is 89 degrees.
At least if this doesn’t fix it, I can catch it, come home and then shut the system off.

Worst case I end up buying a new unit/system.
Maybe the “Smart” Thermostat will help pay for it?

I didn’t know, I guess this is part of life.
Deal with it the best we can and move on.

 

The "smart thermostats" suck imo, there expensive compared to "normal" thermostat, plus their pricey! Their not going to save you any money in the long run, because adjusting the temp up 5 or 6 degrees above or below what you normally keep it set at will keep your unit running longer to keep in to temp, only "real" advantage to the smart thermostat is to see what the temp is in the house when you want if your at work,ect... Best way to do it is to keep thermostat around 2 degrees above or below what you normally keep it at if your gone a lot.

 

I suppose I should have mentioned we have a dog.
She stays inside while we are away.
Really would like to keep an eye on things, even if we get a new unit.

She has access to the garage where it stays cooler.
But it is a bit concerning to me.

 

A baby monitor can do the same AND give you a visual. I had one even years before I had kids to keep an eye on my pup and it displayed room temperature as well.

 

Never thought about that.
We do have cameras around the exterior of our house.
(Thanks to who ever it was that decided to steal our Honda right out of the driveway)
We use the Ring system, I may see if they offer a camera that shows the temperature as well.
Thanks for the idea.

 

How did it work last year??
If the thermostat does not shut off the unit after setting the temp below room temp, then your thermostat is not working as it should.

however, there is a possibility that it is wired incorrectly (depending if it worked fine the previous year)

 

We moved into the house in 2002.
Everything is the same since the day we moved it.
Never changed, repaired, or replaced anything.

Last year when this happened, we just turn the Thermostat Off and back On.
It has worked fine since. Expect for today, when it did it again

 

Depending on your brand it’s a possibility it’s a stuck relay or your board is malfunctioning.

Once had a unit where the spade connector came loose from the board. It would work intermittently.

 

How is your cooling??? Does the thermostat work as it should??

 

It did, we have not used the cooling system in about a month.
I guess I can try it. It only seems to do this on the heat setting.
We just opened to doors and windows to cool the house down earlier.

 

When i quit doing hvac work they were just coming out with the nest type thermostats. They had some sales guy from nest or whoever was making the fancy phone app thermostats come give us a lecture on them and the data they were keeping track of on users. It said most people just ended up not really using them any differently than a normal programmable t stat. I guess if you have a random schedule where your away from home randomly you would probably benefit from a phone controlled tstat, I think they have location sharing on some of them so when you 15 mins or so from home your heat or a/c will kick on.
Sounds like it's the thermostat though if you turn it off and it cuts off the unit, a normal one isnt very expensive.
If it sticks on again you could check the white wire to see if it has voltage when it should be off. They are pretty easy to diy change. I'd try that before I paid a company to come out and take a look at anything else.

 

I forwarded your description of the problem to my Son who has been in this business for 25 years plus. He stated that a thermostat probably would NOT fix the issue.
He said the (some kind of ? ) burners in the furnace are probably out (or going that way) and if that is not it, it's probably your main control circuit board.
Sorry for the bad news -- but you asked for advice from some one that knows these things. He suggests calling a trusted pro in your area -- ask around to get some one you can trust.

 

I’m still curious as to why the “Aux” heat came On.
What I have read, is that the thermostat controls this operation.
And it only comes on when the temperature has fallen or is below a “preset degree”.

For instance, the house current temperature is 5 or more degrees below the current manual setting. (What ever you have it set to). 5 degrees is an example, i don’t know what the Manufacturer has it set to. It is a Honeywell Thermostat.

If there is too great a difference in the current and set temperature, the AUX is commanded ON?

 

Thank you. Don’t be sorry for giving me “bad” news.
It is, what it is. Thanks again.

 

I haven’t done any hvac work in a while but I think that is correct. Aux is for heat strips or backup. And really only comes on when the main heat can’t keep up.

also if you do call somebody it’ll probably be hard for them to really troubleshoot if the problem doesn’t happen while they are there