Hi, I am replacing my thermostat to a progammable unit. i have a hp with aux heat and i want to replace a honeywell(T874R) thermostat with a Honeywell (pro 8000 TH8320U).the old unit has 6 wires connected (R,Y,W,O ,B, AND G) there were also two wires tuckd away( black and brown) the new thermostat has two columns with the following with the RC and the R factory jumped--

conventional.........heat pump------both have the RC/R jumped
RC..(jumped with R)..RC--------i know R goes to R and G to G
R...(jumped with RC)..R---------y to y but where do W,O,and B go?
W........................O/B
Y...........................Y
G...........................G
C...........................C
i have read quite a few post and have an idea where they need to go but i rather know for sure than to take a guess and screw something up.
thanks for any help i can get

 

Are you sure that the t-stat is supports aux. heat? It should have an aux or W2 terminal.

BTW heatpumps and programmable t-stats don't mix. On colder days, the heatpump alone won't be able to recover in a reasonable amount of time. The heat strips will run a lot more, offsetting any savings. Set it at one temperature and forget it.

 

Like said I dont like a programmable tstat on a heat pump. Slow pick up or it will turn the eme heat on to help. They do have some tstat now that pick up slow so it dont turn on the back up heat. But it takes a long time to get the temp back up in the home.

 

Intelligent recovery or not, if the outdoor temperature is near the balance point (as it often is), a heatpump will never be able to recover without running the aux heat.

If you get a new t-stat which works with heat pumps, leave it on HOLD. Draft proof and add insulation to save energy.

 

first don't hook up the c-c or blue to c - bad mojo


r to either rh or rc-leave the jumper
stat
g- g
y- y - with a jumper to W
w- o
I'm pretty sure the honeywells have an aux terminal.

 

my bad--- apperently i have two t stats with a different model # and different options on the wiring. the old tstat has the R,W,O,G,Y and B. the new tstats have the following (TH8320U) has the following optoins RC,R,O/B,Y,G,C,AUX,E,L and Y2 the other tstat (TH8110U) has the following options RC,R,O/B,Y,G,C ----both tstats have the RC and R factory jumped.
thanks for your help

 

Return the TH8110U - it's incompatible with your system.

Follow the installation instructions - the newer models do not require a jumper from W to Y. (though you have to ensure that the system settings are correct for a heatpump so that Y is energized on a call for heat.

For the record:

R = Power
C = Common (directly back to the transformer)
G = Fan
Y = Outdoor unit contactor
Y2 = Second stage cooling (do not connect this unless you have a 2-stage unit)
W = Conventional heat (Furnace, electric heater, etc.)
W2/Aux = Auxiliary for heatpump or 2nd stage heat for a furnace
O = Reversing valve (energized in cooling or heating mode depending on the outdoor unit)
B = Reversing valve (either or re: O terminal)

**I'm not sure what having O and B means**

If you aren't familiar with the above, call a technician.

 

what make and model t-stat do you recomend for a heat pump.
last spring i replaced a older stat with a honeywell rth7000.a/c cycles good but in heat mode it runs all the time and electric bill has increased $60 plus a month as oppossed to last years.

 

I need help wiring my thermostat similar to yours and so far have connected these wires:

Red = RC/R
White = W
Yellow = Y
Green = G

The heat works but can't get the A/C to work. I have a heat pump unit.

Did you get yours to work?

Thanks!

 

your going to need to energize your reversing valve circuit - either o or B
usually 0 but you need a heatpump t- stat