How To Reset An RV Comfort ZC Thermostat

RV Comfort ZC thermostats are one of the more common HVAC control systems in a lot of RVs.

They are generally easy to use and give you full command over what your RV’s rooftop air conditioners are doing.

Though, like any electronic device, there are times when it can have problems, glitches, or needs to be reset.

If you are like a lot of people and you “Lost the instruction manual” then you are probably wondering how do you reset an RV comfort ZC thermostat?

Fortunately, resetting it is usually as simple as turning it off, waiting five minutes, and turning it on again. Though this is not always the perfect fix.

In this article, we’ll take a closer look at some of the more common issues that RV Comfort ZC thermostats run into as well as how to fix them.

This includes instructions on how to install or replace an RV thermostat that has come to the end of its life.

How Do I Reset An RV Comfort ZC Thermostat?

The first thing you should do when you have an RV Comfort ZC thermostat issue is to reset the unit. You can do so by following these steps.

  • Step One: Press 00 on the RV comfort ZC thermostat and hold it down for a few seconds.
  • Step Two: Turn the thermostat off.
  • Step Three: Turn off the circuit breaker or remove the fuse
  • Step Four: Wait 5 minutes to let any ambient charge in the capacitors dissipate.
  • Step Five: After 5 minutes turn the breaker back on or reinsert the fuse.
  • Step Six: Wait for another 5 minutes for the system to fully power up.
  • Step Seven: Move the switch to the “Cool” setting and make sure the temperature is set low enough to activate.

The system should behave normally at this point. If it doesn’t, you might have a more serious problem with either your RV’s HVAC system or the Comfort ZC Thermostat itself has been compromised.

Of course, resetting the thermostat isn’t a perfect fix every time. Especially if there is another fault in the system.

You can then use the following troubleshooting information to restore normal HVAC operations.

Common RV Comfort ZC Thermostat Problems And How To Fix Them

Common RV Comfort ZC Thermostat Problems And How To Fix Them

The following are some of the more common problems you might run into with an RV Comfort ZC thermostat.

You might want to try one or more of these if you’ve fully reset the RV thermostat and you are still having a problem.

1. The RV Furnace Is Blowing Cold Air

If your RV furnace is blowing cold air, and you are certain that the furnace itself is in good working order, then the first thing to suspect is an issue with the propane system.

Check your liquid propane tanks to make sure they are reasonably full and that all the valves are properly open.

If there is a small amount of propane in a tank, but the weather outside is below zero, it might be that the tank froze up and doesn’t have sufficient pressure to send propane to the furnace.

Fixing This Problem

You will need to refill or replace the liquid propane tank. Then turn on the valve before resetting the thermostat.

You might also need to turn the furnace on and off a few times with 30 to 45 seconds between cycles to get the RV’s furnace to once again synch up with the Comfort ZC thermostat.

Also, check the pilot light in your RV’s propane furnace to make sure it is lit.

If it doesn’t stay lit, you might also have an issue with the furnace’s internal thermocouple, which will need to be replaced.

2. The Heater Or Air Conditioner Won’t Turn On

The thermostat plays a critical role in engaging the furnace or the RV rooftop air conditioner based on the temperature you set it to.

If the interior temperature in your RV has crossed that threshold, and the furnace or AC won’t engage at all, it might be a problem at the fuse box or with the backup battery.

Fixing This Problem

In a scenario like this, the first thing to do is check the circuit panel. Flip the 15 Amp breaker or replace the fuse.

Then reset the Comfort ZC thermostat. If this doesn’t reactivate the system after 5 minutes, you should also try to replace the interior battery in the thermostat and reset it again.

3. The System Won’t Power On After Turning Off To Reset

If you turn off your RV’s Comfort ZC thermostat to reset it and it doesn’t turn back on, it is likely a power fault or low battery issue.

Fixing This Problem

You need to check to make sure that all your power sources are correctly connected and that your RVs house batteries are properly charged.

This might mean checking the pedestal you are connected to shore power or making sure that your house batteries have at least 50% of charge.

Also, check all your connections to make sure there isn’t a corrosion issue preventing power from getting to the HVAC system’s components.

Replacing An RV Comfort ZC Thermostat

The unfortunate truth is that even the highest quality RV thermostat will still have a finite lifespan.

If your RV Comfort ZC thermostat has come to the end of its life, you can turn off the circuit breaker and replace it with the following steps.

  • Step One: Remove the faceplate from your existing thermostat and carefully back out the mounting screws, starting with the top screws.
  • Step Two: As the old thermostat starts to come loose, keep a hand on it to keep from prematurely disconnecting the wiring in the back of it.
  • Step Three: Take a picture of the color-coded wires with your phone just for reference later if you need it.
  • Step Four: Pull the wiring harness out as far as it will go without breaking it loose.
  • Step Five: Disconnect the wires from the back of the thermostat. This might be as simple as pulling out the plugs, or you might need to cut the wires.
  • Step Six: If you needed to cut the wires to disconnect the old thermostat, you will need to carefully strip back the protective coating on the wires coming out of the wall by roughly half an inch. This will create enough exposed wire for you to secure the connections with wire nuts later.
  • Step Seven: If the new thermostat doesn’t have plug connections and you had to strip the wires coming out of the wall, you will need to strip the wires on the back of the new thermostat by half an inch as well.
  • Step Eight: Either plug the wires into the back of the new Comfort ZC thermostat or carefully braid the wires together in corresponding colors. Then secure them together with the appropriate size of the wire nut.
  • Step Nine: Check to see if the unit powers on and the display are getting power.
  • Step Ten: Turn on the RV’s propane, or activate the breaker on the rooftop air conditioner.
  • Step Eleven: Turn on the heat or AC to make sure everything is working correctly.
  • Step Twelve: Carefully feed the wiring harness back into the hole in the wall. Then screw it back into the wall.

Can You Replace An RV Thermostat Yourself?

Even if you aren’t mechanically inclined, you should be able to replace an RV thermostat on your own.

If you are truly uncomfortable with the process or you are worried about warranty fine print, a professional should be able to handle the installation for less than $100 plus the cost of the replacement thermostat.

How Long Does An RV Thermostat Last?

The average RV thermostat has an average lifespan of 7 to 12 years. If yours makes it to 15, you should consider yourself lucky.

If your RV Comfort ZC thermostat is more than a decade old and resetting it or other troubleshooting measures have failed to rectify the problem, it likely needs to be replaced.

Conclusion

Resetting an RV Comfort ZC thermostat is usually as simple as turning the unit off, flipping the circuit breaker, and giving it five minutes, before turning it back on again.

Another 5 minutes to let the system power up and your RV’s thermostat should be working like normal again.

If resetting the unit doesn’t rectify the problem, then you should troubleshoot to make sure there aren’t any other faults in the HVAC system.

If your troubleshooting still doesn’t improve the situation, then chances are good your thermostat has come to the end of its life and needs to be replaced.

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    Written By Aaron Richardson

    Aaron and his wife Evelyn have lived on the road since 2017, traveling the country in their Keystone Fuzion. They’ve sought adventure together for 5 years now and have done a lot of international traveling, including RVing in Mexico. Aaron is the co-founder of RVing Know How, where he shares their experiences and RV-related tips to make life better for other RV owners. If you’re looking for Aaron, chances are you'll find him either pedaling the backroads or hiking to sunset spots.

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