Trouble with Honeywell RTH7000 thermostat changeover.

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Old 01-07-09, 06:52 AM
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Trouble with Honeywell RTH7000 thermostat changeover.

Hi all
Great forum here.
Here’s my dilemma. I have a heat pump as primary heat source with an oil furnace backup. I wanted to change the old thermostat to a new programmable. I purchased the Honeywell HTR 7000 series. The old thermostat was a Carrier MS21 (only model # I could find). I removed the old unit and marked all the wires according to the instructions from the new unit. There were two sets of cables coming from the furnace and heat pump unit, one with a black and a white wire, one with red, white, black, green, blue, and orange wires. The hook up for the old unit was as follows.
R - red
R1 - black from black and white pair
C - White
Y1 - White from black and white pair
W2 - Black
G - Green
E - Blue
O - Orange
I hooked up the new thermostat according to the installation manual as follows. RC and R are jumpered.
RC - Red
R - Black from black and white pair
O/B - Orange
Y- white from black and white pair
G - Green
C - White
E - Blue
Aux - black

From the installation manual and the section on system setup, I have parameter 0170 set to 7, 0190 set to 0, 0240 set to 5, 0270 set to 5, 0300 set to 1.
When the new thermostat calls for heat the furnace fan comes on but the compressor does not. After the heat in the house drops down far enough, the oil burner kicks in.
The indicators on the front panel show the proper function that are supposed to be taking place. The system was working fine with the old thermostat before I changed it out, and after I notice the problem I put the old back in again to verify that something wasn’t damaged. It again works fine with the old thermostat.
Any help would be appreciated.

Wipper
 
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  #2  
Old 01-07-09, 07:57 AM
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From the installation manual and the section on system setup, I have parameter 0170 set to 7, 0190 set to 0, 0240 set to 5, 0270 set to 5, 0300 set to 1.
When the new thermostat calls for heat the furnace fan comes on but the compressor does not. After the heat in the house drops down far enough, the oil burner kicks in.
How many wire go to the outdoor unit? How many wires terminate at the furnace?

Sounds like it may not programed correctly, try setting function 190 to 1, this should direct a call for heat.
 
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Old 01-07-09, 09:34 AM
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Update
I spent the time last night to do some tests with my voltmeter on the old thermostat still connected so the I can understand what is going on. All measurements were using C as common, R and R1 as 24vac supply
With the unit calling for heat only
C to Y1 = 24vac
C to W2 = 0vac
C to G = 24vac
C to E = 0vac
C to O = 0vac
With the unit calling for Aux + heat
C to Y1 = 24vac
C to W2 = 24vac
C to G = 24vac
C to E = 0vac
C to O = 0vac
This is how I suspected it to work and it does. I did not test the cooling cycle.
The RTH7000 unit is battery powered and operates without being plugged in. I checked parameter 190 and made sure it was set to 0. I was able to use my meter switched on continuity to test all leads to see what was happening during different stages.
Theses are my results. I have Rc and R jumpered.
With the unit calling for Heat only
Continuity between R and Y and G
With the unit calling for Heat + Aux
Continuity between R and Y and G and Aux
With the unit calling for Cool
Continuity between R and Y and G and O/B
With the unit calling for EM Heat
Continuity between R and E and G and Aux

Based on the results that I found when testing the old thermostat, my results from the new is exactly what I would have anticipated. When I plugged in the new, the compressor did not come on again.
All measurements have been taken at the thermostats and not on the furnace or compressor. I have yet to tackle this yet as the wiring on the furnace was IMHO installed in somewhat of a hurried mess. It will take some time to identify everything.
This should have been a direct swap out.
Wipper
 
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Old 01-09-09, 09:18 AM
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Just wondering if someone might have an answer before I take this unit back. Any help would be greatly appreciated.
Thanks
Wipper
 
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