ADC T3000 Tstat with Heat Pump AUX heat running too much

Hello,
I have an ADC t3000 thermostat installed with my water furnace geothermal two-stage heat pump with LP backup auxiliary furnace.

All seems to be working as it should, however I noticed that my LP furnace is running far too often and I’m wondering if you can assist me with any particular settings that would adjust this.
I am a surety customer and I believe you can see my advanced settings on the thermostat, which I have tried to increase pump staging delay but I continue to notice my propane firing instead of the Geo running to heat my home.

My Geo is on green power and it is far more cost-effective for me to run this for hours, as is designed, then to kick it over to my auxiliary heat source.

Considering the cost of propane I am ready to reprogram the thermostat to tell it I do not have a backup heat source until the time comes that I lose power just to stop burning through the gallons of LP I have so far.

As always, thanks so much for your time, consideration, and any input or assistance you can provide.

Justin

Do you notice the temperature dropping a couple degrees below the set point often? In this case it may take a little longer for the Geo pump to keep up with the temperature drop.

One thing to try in this case to keep the aux stage from triggering as often is to adjust the heating differential setting on the advanced page. Try increasing that differential so that the temperature must drop further before the aux stage kicks in.

Hi Jason thanks for the reply.

No I do not see the temp drop that often, but I did have my away degree setting about 3° off of my home setting.

My differential was set at 3° and then I change to 5° yet the furnace still seemed to kick on with LP.

Ideally my LP furnace should be used solely as an emergency heat source as my Geo is sized appropriately for my home and other than needing to run a bit longer, should not require AuX heat for a supplement. This is especially true right now as we are nowhere near the coldest days for my area which the heat pump is sized for.
I have since removed the secondary heat system from my thermostat to remove any chance of firing the LP.

My fear here would be of course if we lost power and I happen to be away, my LP furnace would not turn on to keep the house heated which could be disastrous in the winter. Otherwise I do not anticipate being away for any extended time.

I suppose I could reconfigure the thermostat when needed, for being away an extended period of time…not ideal either.

Can you confirm this is how the various settings work?:
I thought the temperature differential was also what was used to engage the next stage of my heat pump along with the pump timing delay?

Which one takes precedence?

I do not want my heat pump to run in the first stage for longer than it needs if it could satisfy the heating call within the second stage.
What I do not want to have happen is the pump delay time run out on my heat pump second stage which I believe would then kick off the aux LP heat stage, correct?

If I set the aux stage delay timer to a high setting does this delay the LP from coming on for that many minutes after the second stage heat pump has been running or does that require the LP to run for however many minutes I set on that delay until it shuts off?

I thought the temperature differential was also what was used to engage the next stage of my heat pump along with the pump timing delay?
Which one takes precedence?

It’s my understanding that these two settings work in tandem and the first criteria met activates the next stage.

In general setting a longer timer or higher differential should increase the time before additional stages run, including the aux.

I’m happy to reach out and see if I can get extra clarification from ADC.

I think so that we can best assist and describe the issue to ADC, we will need to provide them with data on the frequency the aux is running.

Set your delay and differential and then test over a period of time. Note how long it takes after a call for heat before the Aux furnace kicks in, and note the temperature when this happens.

Some examples of when the aux is running should help identify what is going on.

Hi Jason,
Sorry for the delay, but thank you for your reply, as always!

I have since removed the Propane furnace as an AUX/Emergency unit to my Thermostat, as it was just running far too often.
No matter how I adjusted the pump delay timings, or differential degree, the furnace would kick on after the pump staging delay expired.
At no point regardless of my differential setting, did the temp range go beyond 2*F; it seems the staging time delay would run through stage 1, then stage 2, then go to furnace based upon my setting.

I did not have any issues to this scenario when I utilized the Water Furnace provided Thermostat, as I assume there is different programming within.

Ideally, my furnace is not Auxiliary, but EMERGENCY only.
The ONLY time I want my propane furnace to turn on is if I lose power.
For a heat pump, as I’ve read and been told by 3 different HVAC professionals, this (power loss) is the only time it should utilize the secondary heat source, as they’re designed to run non-stop if need be during the coldest days.

I hope this helps if you’re able to reach out to ADC for clarification. I am more than happy to provide further details if they require.

The ONLY time I want my propane furnace to turn on is if I lose power.

I don’t believe this sort of setup is possible in ADC settings, but I will check with ADC to see what options are available

Yeah, there is no way for the T3000 to function this way in and of itself, but you should be able to instead use a separate 24VAC relay to monitor power from the Heat pump (the R terminal output) and switch on the Propane furnace only when the Heat pump is down.

Thanks Jason.
I guess the ADC T3000 doesn’t have similar code as did the Water Furnace thermostat in that it won’t pull the Aux/Emergency heat unless there’s actually an issue. The T3000 seems to go by the differential and time delay and moves through the stages.

To your point with the additional/separate relay, I’d still have the T3000 programmed without the aux/emergency propane furnace, as is now, but if power goes out it’d call for the heat pump and energize the relay which would turn the furnace on; correct?
It seems the relay would only be connected to the R terminal on the Heat Pump as a switch if power is lost?

That is the idea, though I am not sure exactly how your system would be triggered, and where power is coming from for the propane furnace if power is out.

The thermostat relays 24VAC from the R input to W/W2/Y etc. for heat and cool calls. If the propane furnace is 24VAC control, do you have a generator for it?

I won’t be able to provide exact installation steps for something like this, it is outside of the scope of the thermostat, so I would recommend asking your HVAC specialist how to wire it with a relay in the way you desire.

The confirmation and your explanation helps and will get me on the right path.

Thank you.