So posted this but didn’t have all the images when I made it and things changed. 

I’ll place the original post under this. Seeking general advice as this cost over 35 grand and it’s not working. 

So as an update I think I know the issue. My attic and basement are completely finished livable spaces. When this was installed they installed 2 units. The upstairs is a 3 ton unit for the attic and second floor. The other unit is a 2.5 ton unit for the downstairs (1st floor and basement) but here is my issue. My ceilings are 10ft tall. And my 1st floor is 1590sqft feet the basement is the largest space at 1610sqft. Livable spaces. Not counting closets/bathrooms. The upstairs second floor is 1540sqft and the attic is 1480sqft: so it’s slightly more than 3000sqft per unit and over 6000sqft for the whole house. So I think these units are extremely undersized. The upstairs seems to be doing okayish now but I think purely because that unit is the bigger one and heat rises. Does it seem like these are undersized? It’s 5.5 tons total for 6,000sqft. My hvac says if anything it’s bigger than it needs to be but it never gets to temp. I’m waiting for him to come out with a Bosch tech now.

Also they tried to tell me the issue was a draft. But I can shut the heat off and even in the negatives outside it takes 35 minutes just to drop 1.5 degrees. 5 hours to drop close to 10 degrees and that was during a power outage. So nothing was running. I insulated the windows where they said the draft was an issue and of course the same problem is occurring

But of course it couldn’t get up to time and kick off in the 30s-50s and now it’s in the negative and the house at this point is lucky to stay in the upper 50s with them running nonstop. The units are definitely working correctly too. I just don’t know what to do at this point. I can’t afford to pay another company to come in after the cost of this. And he has a guarantee policy for all his work for either 2 or 3 years. 

Original post: 

So I just had a new hvac system installed. I opted to replace their $29 Honeywell non programmable thermostats with two Sensi 2.

To cover the details they installed a 2 ton unit for the upstairs and 3 ton downstairs. Bosch heat pumps with aux electric heat. This allowed the systems to be installed easier without running ducts through the walls. So it was heating fine the. Before they finished they replaced the Honeywell thermostats. At first there was some confusion on how to set up the Sensi 2. It ran as expected but did kicked off for decent periods of time before kicking on again. Well as soon the Sensi 2 were set up the stopped kicking off. Or at least never stopped calling for heat. And the blower which is on auto, never stops running now either.

Under configuration they said the flow is B. After awhile it was decided to set outside to HP1 and inside to EL1. It gets to temp. It maintains temp. But it just never stops calling for heat with these Sensi 2 where it did with the $29 Honeywell. I can get model numbers if need tomorrow when I get home. And a picture of the wiring on each thermostat.

I read that because it’s more than one stage it should be HP1 then EL2. So I jut tried that. I’m not sure if it’s a wiring issue or these Sensi 2 just aren’t doing the job.

For additional context I’m heating 4 floors. Basement-attic. All finished living areas. The basement first and second floor are around 1500 sqft each. So 3 ton is handling just over 3,000 sqft and the 2 ton is handling around 1500 for the second floor then the attic is between 1100 and 1200 sqft. For second floor every room has at least 2 vents pushing and 1 for cold air return. Downstairs is a little different. Dining and living room have 2 pushing per room. 1 in entrance/hall. 1 in kitchen. Then there is one big air return in the living room. Then there is one per room in the basement so 4 and we have one that runs to a side room we have. Oh and then one on each side of the finished attic space. And it is tall ceilings. Upper half has vent in ceilings. Lower half is all floor other than basement is the ceiling.

I’ve also tried changing the cycle from medium to low. Aux boost off for efficiency or on. Just never kicks off at the thermostat now. Is this just bad thermostats for this and I should use different ones? Or is this something else? If I remember before work in the morning I’ll get pictures of at least the wiring.



So they are both wired exactly the same. Update as well. At least one of the units wasn’t defrosting at all. So it’s frozen and off now and we have went to electrical only. But both are essentially always running. I’ll post the usage next. Usage pictures attached as replies on this post. It did just get brutally cold but prior to this it was mid 30s to 50s and was still running 22-23 hours a day with about the same aux as well. I’m not sure if the two heat pumps aren’t just working well or maybe not big enough as well. My hvac said these Bosch ones are rated for -20 and to expect the aux of course which I did. But my sisters house is about as big but hers kicks off for big periods of time even thought my house has updated and been re-insulated  and hers is not insulated well right now

 

Bosch/Sensi Thermostat plus sizing concerns