gas heat or 2nd stage heat overide

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
N

Neal

Well-known member
Joined
May 13, 2009
Posts
539
Location
East Texas
Many times when heat is required in the AM, the heat pump only runs for a period of time, then turns on the gas heat. We would like to be able to keep only the heat pump running most of the time, without having to watch how far above actual temperature the thermostat is set.

Does anyone know if it is possible to install a switch in the Winnebago heat  pump/gas furnace heating system, so that the gas furnace would be disabled and continue heating with the heat pump until the added switch was turned on?
 
What is the outside temperature when this happens?  It's normal for a heat pump system to switch to the furnace when the outside temperature is too low for heat pump operation.  This is typically when the temperature is below about 40F but may be as low as the mid 30s.  This function is independent of the thermostat set point.
 
On mine if the outside temp is above 40, I can use the heat pump if I set the thermostat at only 3 degree increments. If I go above 3 degrees the propane kicks in.
 
The gas furnace will start (while you are on heat pump) if the thermostat set temperature and room temperature are more than five degrees apart.  Try keeping your set temp under five degrees.  The heat pump could operate with air temps of the 30s depending on the humidity - lower the humidity the lower it will operate.
 
I think he understands how the t-stat works. The question was about modifying the control circuits to include an override switch. The only way I can see to do that would be to disconnect the control line form the t-stat to the furnace and insert a switch there. That would stop the "heat demand"  signal to the furnace, but it would do it in furnace only mode as well as when the heat pump wants help.

Does your heat pump continue to run after the furnace comes on? That's how it works in my American Tradition with the Atwood Comfort Control System t-stat.
 
Ned said:
What is the outside temperature when this happens?  It's normal for a heat pump system to switch to the furnace when the outside temperature is too low for heat pump operation.  This is typically when the temperature is below about 40F but may be as low as the mid 30s.  This function is independent of the thermostat set point.
Click to expand...

Most of the time, the outdoor temp will be above 40 degrees. We may either have the system off overnight or may have gone to bed with the air on, then wake up needing to warm up the house. We like to get up, turn the heat on to a comfortable temperature, then get back in bed & wait till the house warms up.
 
tallyo said:
On mine if the outside temp is above 40, I can use the heat pump if I set the thermostat at only 3 degree increments. If I go above 3 degrees the propane kicks in.
Click to expand...

Yes, we try to do this also, but it means I have to be up & keep moving the t-stat setting up gradually.
 
RV Roamer said:
I think he understands how the t-stat works. The question was about modifying the control circuits to include an override switch. The only way I can see to do that would be to disconnect the control line form the t-stat to the furnace and insert a switch there. That would stop the "heat demand"  signal to the furnace, but it would do it in furnace only mode as well as when the heat pump wants help.

Does your heat pump continue to run after the furnace comes on? That's how it works in my American Tradition with the Atwood Comfort Control System t-stat.
Click to expand...

Sometimes the heat pump continues to run & sometimes it cuts off. This is why I questioned whether putting a switch in a 2nd stage t-stat wire would work or not. It seems there may be a logic module which controls the heat pump operation under some circumstances.
 
John Canfield said:
You could call RVP and run that by their techs, but they might not be willing to help you hack the thermostat.
Click to expand...

excellent idea. Just might try that. Chances are, the t-stat may get hacked even if they do not wish to participate.  ;D
 
tallyo said:
I have the Little Woman trained to handle this job! ;D
Click to expand...

Some people have all the luck.  ;D  Since I am usually the first one up, I guess she has me trained.
 
I added a 2nd digital set-back thermostat just to control the gas furnace.   This is a very easy project since the gas furnace uses only two wires to turn heat on/off.  I disconnected the control wire from the Coleman thermostat so that I don't have it calling for gas heat when the temp is >5 deg.  But what I like when dry camping is not having the furnace coming on (draining the battery) all night but only in the morning when you set the time/temp in the digital t-stat.

If your Winnie is like my '04, you have a Coleman-Mach True Air thermostat.   The thermostat has two set of wires, one set to a 3-pin connector goes to the gas furnace, and the other is a 9-pin going to the heat pump.

If you wire a switch in-line with the WHITE wire on the 3-pin connector, you will force the furnace off when the switch is open.  When the switch is closed, everything operates like normal.

If you want to install a second digital thermostat to control the gas furnace, you need to connect the WHITE wire noted above and also use the RED/WHITE wire on the 3-pin connector.  When these two wires are shorted together the furnace will come on.   I bought a digital Ritetemp 8022C t-stat at Home Depot for about $35.  It is programmable so you can set for say 65 deg at night and then 75 deg in the morning 30 minutes  before you plan to get up.  It runs on two AA batteries for around 2 yrs.  It has relay  contacts that  close to turn on the furnace.   On the RiteTemp,  you connect the white wire to W ternimal and the red/white to RH terminal.   It's as simple as that.
I see that Home Depot doesn't sell the 8022 anymore, but I just checked and they do sell 6022 for $25.  The terminal connections are exactly the same as mine.

Check it out:RiteTemp 6022
 
Duner said:
I added a 2nd digital set-back thermostat just to control the gas furnace.   This is a very easy project since the gas furnace uses only two wires to turn heat on/off.  I disconnected the control wire from the Coleman thermostat so that I don't have it calling for gas heat when the temp is >5 deg.  But what I like when dry camping is not having the furnace coming on (draining the battery) all night but only in the morning when you set the time/temp in the digital t-stat.

If your Winnie is like my '04, you have a Coleman-Mach True Air thermostat.   The thermostat has two set of wires, one set to a 3-pin connector goes to the gas furnace, and the other is a 9-pin going to the heat pump.

If you wire a switch in-line with the WHITE wire on the 3-pin connector, you will force the furnace off when the switch is open.  When the switch is closed, everything operates like normal.

If you want to install a second digital thermostat to control the gas furnace, you need to connect the WHITE wire noted above and also use the RED/WHITE wire on the 3-pin connector.  When these two wires are shorted together the furnace will come on.   I bought a digital Ritetemp 8022C t-stat at Home Depot for about $35.  It is programmable so you can set for say 65 deg at night and then 75 deg in the morning 30 minutes  before you plan to get up.  It runs on two AA batteries for around 2 yrs.  It has relay  contacts that  close to turn on the furnace.   On the RiteTemp,  you connect the white wire to W ternimal and the red/white to RH terminal.   It's as simple as that.
I see that Home Depot doesn't sell the 8022 anymore, but I just checked and they do sell 6022 for $25.  The terminal connections are exactly the same as mine.

Check it out:RiteTemp 6022
Click to expand...
Thanks for the info. We did install a toggle switch in the white wire yesterday. Will see how we like this on our next trip out.
 
Neal - I modified mine with a switch in the white wire of the 3-wire furnace control harness several years ago. It has worked flawlessly.... It stops the stat from requesting "help" from the furnace when you are requesting electric heat. Just remember to switch it back on if you want to select gas heat.
 
You must log in or register to reply here.

Latest posts

Members online

Total: 1,047 (members: 32, guests: 1,015)

Forum statistics

Threads
131,974
Posts
1,388,479
Members
137,723
Latest member
CarlSpackler
Back
Top Bottom