Florida home has a heat pump split system. Condenser is an Ameristar M4hp4042a1000aa. Air Handler is an Ameristar M4AH4044A1000aa. The fan and cooling in our current heat pump thermostat work but when the heating option is on, the fan works but the home does not heat up at all (even after many hours). This is how the thermostat is set up (picture included).

Old Thermostat (Honeywell Thermostat 50018270-002 - no batteries used):


Switching the position of orange to O did not fix this. Moving the white wire to E also did not work. As a test, we switched our old thermostat with a new smart thermostat (Honeywell rth6360d1002-1738) and somehow the heating now worked BUT the cooling stopped working. The home raised in temperature within minutes. The wirings were all the same in this new thermostat EXCEPT B/O was one connection on the back panel, and the white wire ONLY worked when it was placed on W, not W2/Aux or E. There is no defrosting situation here with the outdoor condenser.



We reconnected the old thermostat and the situation there is the same, but when we reconnected the new thermostat to get some heat again, it stopped working altogether. Right now the old thermostat is set up and I'm having trouble figuring out how to get the heating to work. It's clear that the cooling and heating functions of the heat pump are fine. I have no idea how to troubleshoot this and would appreciate some help to avoid freezing at our place. I included photos of the wiring in the outside condenser for reference. I can't find a manual for my exact model but it seems based on other manuals for Ameristar condensers that it utilizes B for the reversing valve.

Thank you in advance.

 

Welcome to the forums.

Not sure what you mean here. You said the heat wasn't working.
Is the heat pump working or not ?

Based on your wiring you have backup electric heat.
The thermostat must be programmed for B power on heat. Default is O power on cool.

Ameristat heat pump manual (pdf)

 

Hello and thank you for the comments.

When I mentioned that heating/cooling work, I meant that the heat pump, when wired/setup correctly, appeared to work properly (although they couldn't switch from heat to cold and vice versa). I doubt that me replacing the thermostats has suddenly broken the entire heat pump's ability to function.

For thermostat programming, I can't find the manual for the old thermostat anywhere. I found out how to program it but I don't understand what the function numbers refer to. I see functions "6, 8, 9, 14, and 15" but newer thermostat manuals only list "6, 8 and 14."

For the smart thermostat, when the heating did work, I had forgotten to switch to heat pump mode (it was set to Conventional Forced Air Heat by default). When I re-installed the new one, I reprogrammed it to work as a heat pump to be used with B. I placed the white wire on W2 like it says on the manual (here) and neither the cooling nor heating worked. I then tried to replicate the default setting on the smart thermostat like when it did work previously and yet neither cooling or heating worked.

If I had some reference for what the functions on the old thermostat are and what the options mean, I may be able to fix this.

EDIT: I provided the wrong model number for my old thermostat. It's actually a TH3210d1004. I did find it's manual and will troubleshoot it further tomorrow after reprogramming it.

 

That is pretty much a basic thermostat. Those are just fine alignment settings.

6 - aux heat ------> 9
8 - emer heat ----> 9
9 - comp cycle per hour ----> 4
14 - temp display -----> 0 - Fahrenheit
15 - comp protect ------> 5 (five minute restart)

 

Thank you. I just tested the unit after programming the old thermostat and when I turned heating on, I felt air coming through the ducts but the outside condenser unit was not spinning. The air coming into the rooms was not warming anything.

 

When you go to cooling mode.....R gets connected to Y and the compressor runs in cooling mode
When you go to heating mode....R gets connected to Y and B. The compressor runs and the reversing valve gets 24v on the B wire to activate the valve into heat mode.

If your thermostat isn't doing this..... try connecting the wires manually.
Connect Y and B and G together first..... and then connect R to them.