Just bought a home with a bonus room upstairs - split unit AC.
Thermostat on the first floor was a 2 stage totaline P474-0100 and
upstairs was a single stage manual robertshaw CM200.
I bought two Honeywell 5-2 Day Programmable Thermostat's to replace
both. Replacing the bonus room went well. When I replaced the
totaline the unit would not engage (nor the fan). All contacts were
The bonus room was a four wire (no Rc, just Rh). The first floor had a
five wire and the totaline marked it "C" - matching it up to Rc on the
honeywell (I also removed the Rh/Rc jumper). Everything appeared to be
wired up correctly.
First - the Honeywell YRTH230B1009 stated - "For single stage heating
and cooling or millivolt systems" - so from what I read I took a step
back from the 2 stage totaline moving to the single stage honeywell.
Second - was there a reason why there was a 4wire single stage in the
bonus room vs the 5 wire 2 stage on the first floor - would it cause
the problems when I installed the second honeywell?