RV Comfort.ZC Thermostat won't go to zone 2/3

[VGreen]

I have an RV Comfort.ZC thermostat that controls 3 zones in my unit. Just a few weeks ago it would only go to 'Zone 1', and when i pressed the zone button it wouldn't advance to zone 2 or zone 3. I had full functionality in zone 1, but couldn't get to zone 2/3. I assumed i had a bad unit, so i ordered another thermostat. Before it arrived, i returned to the RV and guess what, thermostat worked perfectly. Well, now we are a month later, and now it won't advance to zone 2/3 again. So, i installed the new one, and same thing, only gets to zone 1, won't advance to zone 2/3. So, both thermostats are doing the same thing. Any ideas? I've tried turning off all power and waiting 5 minutes, still does same thing.

[Kevin Bell]

Originally Posted by VGreen

I have an RV Comfort.ZC thermostat that controls 3 zones in my unit. Just a few weeks ago it would only go to 'Zone 1', and when i pressed the zone button it wouldn't advance to zone 2 or zone 3. I had full functionality in zone 1, but couldn't get to zone 2/3. I assumed i had a bad unit, so i ordered another thermostat. Before it arrived, i returned to the RV and guess what, thermostat worked perfectly. Well, now we are a month later, and now it won't advance to zone 2/3 again. So, i installed the new one, and same thing, only gets to zone 1, won't advance to zone 2/3. So, both thermostats are doing the same thing. Any ideas? I've tried turning off all power and waiting 5 minutes, still does same thing.

This malfunction may be caused by a control box issue. Each upper unit has a control box in which there is a jumper to set it’s zone designation and HP status. If one control box has an issue it will affect the entire system.
You don’t mention what kind of RV this is in, but older units that utilize 12vdc fluorescent lighting caused a lot of thermostat issues from ballast noise in the dc power system.
I would strongly suggest having the system professionally diagnosed by your servicing dealer or one of our NIRVC locations to prevent spending a lot of money doing part change outs in hopes of resolving.

[Skip426]

Zone one ( front roof air conditioner ) is the hub of the system .
The other roof air conditioners and furnace ( aqua hot ) must communicate with the hub in order to show up on the thermostat .

Problems with the hub unit control board or the connecting cables between roof units have to be investigated .

[Mwoodofd]

I believe that the thermostat has a fuse on it in the back. I have seen other pull that fuse to reset the thermostat vs just removing shore power and 12V power. If you have not tried that, may be worth a try.

[voltdoc]

Originally Posted by Skip426

Zone one ( front roof air conditioner ) is the hub of the system .
The other roof air conditioners and furnace ( aqua hot ) must communicate with the hub in order to show up on the thermostat .

Problems with the hub unit control board or the connecting cables between roof units have to be investigated .

This is incorrect regarding the Entegra coaches from at least 2012 forward, there is no hub. The Aquahot is exclusively controlled by the tstat, it does not communicate with the roof units.

But yes the network wiring probably runs to the front unit first then daisy chains to the other two. Each AC unit has a control box on the roof. The thermostat communicates with the control boxes via a proprietary low speed network. Each control box has unique settings (physical hardware jumpers) as described by Kevin Bell so it can be "addressed" by the tstat.

Given your intermittent symptoms, as Kevin mentioned, interference is a possibility. Especially with the pre-2015 units which used a 1 wire network. AFAIK from 2013 and up Entegra did not use any fluorescent fixtures, but have you added any electrically noisy devices or appliances? Nearby wifi devices?

Otherwise it sounds like perhaps a poor wiring connection somewhere. I would check the wiring connections on the roof starting with the Zone 1 (front) AC unit.

What is your coach year/model? The thermostat model and network specifics changed in 2015. Prior to 2015 the tstat was wider than tall, 2015 and up the tstat is taller than wide.

https://photos.app.goo.gl/o4BnG3sCTta3BYWx6

The photo above shows the control box on my 2017 coach. It is located in the return air plenum, so the inner cover needs to be removed to get to it. The two wires on the far right are the network connections (Sig1, Sig2). On pre 2015 coaches the control box will be different and I think there is only one network wire.

Check the quick connect terminals for tightness and corrosion. If corrosion is present treat with a de-oxidizer product.

This document has more info for 2015 and up:
https://drive.google.com/file/d/1uOy...w?usp=drivesdk

Good luck.

[bevandtomH]

Once you’ve found your issue and have resolved, it would be a good time to upgrade to a Micro Air T-Stat. You will appreciate the extra functionality plus WiFi controllable.

[RayandWendy]

I agree 100%. It's one of the best and easiest modifications I've made to our coach.

Later...
Ray

[VGreen]

2015 Entegra Aspire. It's 102 here this week, so waiting until next week to get on the roof! Then I will check into the wiring as described, and the control box looks relatively cheap, so will go ahead and get one on the way just to be safe! Haven't added any appliances of anything electrical, but, have added some Roku devices to our TV's that connect to a Mifi that we bring with us. So when i go back over i'll make sure those are turned off and give that a try also! Thanks for the suggestions