Which HAI Thermostats for Dual Fuel Heat Pump systems

snickster

Member
I have made some previous posts on this subject , however I'm probably more confused than ever on which HAI stats to get.
I purchased 3 RC 100Bs from 2 different online dealers after explaining what I needed .
Well, the HVAC guy came by today to connect them and work on a few airflow issues.
One of them appears to be just what I need and is working fine with the Heat Pump that heats and cools the upstairs.

Downstairs we have 2 Dual Fuel (NG furnaces tied into Heat Pumps). He the stats wouldn't work properly with the DF system and would not turn the heat pumps off when the furnace was running.
So now I have to hopefully return the other 2 unopened thermostats and replace them with another model. The question is which one ?
These are units single stage heat pumps with a high efficiency Furnace.
It would seem to me that if I have to go with the more expensive newer HAI stats , that the HAI RC 1000WH is what I will need to go with.
If anyone has any input on this , I will appreciate your input , as I want to be sure and get the correct stats this time !

Thanks !
 
Thanks ASI

The confusing thing is my neighbor , who is responsible for me wiring my house has the same stat wired up to his duel fuel system . From what my HVAC guy said it would be able to turn the NG furnace on and off but not disengage the heat pump while the furnace was operating. That would really be inefficient !
 
Perhaps this is a question for HAI support. I bet you can fire off an e-mail to them and see what they say. Perhaps they can provide you with a wiring diagram that you can take back to your HVAC guy if they confirm the thermostats should work.
 
The older RC series thermostats are not designed for Dual Fuel. The RC100B will turn on the Aux heat at the same time as the compressor when setup as heat pump. The RC100B also does not use balance setpoints which is common in dual fuel applications. There is probably a way for your system to turn off the compressor when using the Aux heat using an external relay. You could also do the same thing for balance setpoints using the omni and some very specific program lines to emulate this. This would be a lot of work and I do not suggest this, especially when the RC1000 & RC2000 series thermostat will do this all for you.
 
Thanks for the comments . The suggestion to call HAI support was on target and I appreciate all the comments made on the subject.

As Rarbour mentioned ,I found out that there is a detailed work around for the RC100B thermostat to make it work with a DF system , but you have to give up the defrost mode on the heat pump to do it and add an inline part. My HVAC guy says I need to keep the defrost feature ,

I have a request in to ASI (where I purchase the RC100Bs ) to accept the return of the stats (unopened) that I bought last month and let me trade up to the newer series of stats for the increased difference in price . I talked with ASI about it 2 days ago and still don't have an answer. I wouldn't think it would be a problem since these stats cost considerably less. The issue seems to be that they are now discontinued even though they are still on thier website. I really had to search afround the country to find the third one , so they are hard to come by. If they suits somes needs it will save them some $ over the new models.
I'll keep updating how this pans out.
 
The older RC series thermostats are not designed for Dual Fuel. The RC100B will turn on the Aux heat at the same time as the compressor when setup as heat pump.
Is "Dual Fuel" support any different from having a "heat pump with auxiliary electric heat strip" support? I don't have my RC100B installed yet, but I assumed it would work since it is advertised as a "2 Stage Heat/1 Stage Cool Heat Pump Thermostat". I assumed my two stages are 1=heat pump and 2=heat strips. What am I missing here? I sure don't want my heat strips running unless it is so cold that the heat pump cannot keep up (not often in Florida).
 
The older RC series thermostats are not designed for Dual Fuel. The RC100B will turn on the Aux heat at the same time as the compressor when setup as heat pump.
Is "Dual Fuel" support any different from having a "heat pump with auxiliary electric heat strip" support? I don't have my RC100B installed yet, but I assumed it would work since it is advertised as a "2 Stage Heat/1 Stage Cool Heat Pump Thermostat". I assumed my two stages are 1=heat pump and 2=heat strips. What am I missing here? I sure don't want my heat strips running unless it is so cold that the heat pump cannot keep up (not often in Florida).

Wayne,
It sounds like you have a normal heat pump and the RC100B should fully support your system. Dual fuel heat pumps normally have a gas aux heat. This is more common in cold weather climates (north of Florida), where staying below freezing is normal. As far as functional differences, the dual fuel systems are designed so that only the heat pump or the aux heat will be on at once, not both. This is different than a normal heat pump where the aux heat can compensate the heat pump when necessary, not completely take over. There are a few other differences, but if your aux heat is not designed to be the sole source of heat in the harshest climates for your location, you have a normal heat pump and the RC100B will suit your needs.
 
snickster,

I'd give ASI (assume you mean ASI Home) another call. This sounds very unlike them, but I guess even the best business occasionally drops the ball.
 
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