Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > THE OWNER'S CORNER FORUMS > Thor Industries Owner's Forum
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 12-07-2022, 01:51 PM   #1
Junior Member
 
Join Date: Aug 2021
Posts: 7
Unhappy 2011 Tuscany Heat Pump intermittent

I am wondering if any of you smart people out there have any experience with a Coleman Mach AC with heat pump and a RVcomfort.hp thermostat. We are currently in southern Oregon and are using the HP to keep the MH warm. The other night the temp dipped quite low (close to freezing). In the morning I noticed the display on the thermostat was blank and it wasn't responding. I pulled it out of the wall and wiggled wires. Nothing seemed to be loose. Over the next 2 or 3 days I tried sourcing out a replacement. Upon returning to the MH one afternoon, I noticed the thermostat display was back on and responding to changing the set point for electric heat. Magic right? Well now the thermostat is not operating again and am wondering if the problem is in the thermostat or something with the AC/HP.
Any help you can provide would be appreciated. TIA
R-Jackson is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 12-08-2022, 07:58 AM   #2
Senior Member
 
Join Date: Aug 2019
Location: Eastern outskirts of Dallas, TX
Posts: 2,629
Your problem is likely not the thermostat - you need to be looking at the 120vac wiring in the power entry junction box (normally accessed behind the filter grille from inside of the coach).

It sounds like a poor connection in that box that expands and contracts with heating as current is pulled thru the connection (s).

Turn the power off, access the junction box, look for over-heated/burned wire insulation. Remove wire nuts and check for marginal connections/signs of over-heated wire/insulation.
If nothing found, closely inspect any circuit/connection-termination points for signs of burning/discoloration.

Repair as needed.
__________________
‘91 Ultrastar Champion‘02 Georgie Boy Landau 8.1l Workhorse
‘03 Jeep Wrangler TJ 2018 Jeep Wrangler JK toad
MrMark52 is offline   Reply With Quote
Old 12-09-2022, 10:15 AM   #3
Senior Member
 
triplewide's Avatar
 
Join Date: Mar 2015
Location: Greensboro, NC
Posts: 2,390
You can also check for +12 v DC voltage at the thermostat when it is not working. I think it is the red wire. If no voltage at the thermostat the issue it is probably where MrMark52 suggested. If voltage is there then check for ground to thermostat. With good 12 vdc and good ground the thermostat should at least light up the display.
__________________
1998 Min Winnie, 2000 Winbago Journey, 2015 ACE 29.3
2016 Thor Miramar 34.2
triplewide is offline   Reply With Quote
Old 12-09-2022, 04:36 PM   #4
Junior Member
 
Join Date: Aug 2021
Posts: 7
Thanks. Are you talking about the filter in the ceiling at the A/C unit? This makes sense. See my next update.
R-Jackson is offline   Reply With Quote
Old 12-09-2022, 04:38 PM   #5
Junior Member
 
Join Date: Aug 2021
Posts: 7
Thanks. I have 12 volts at the thermostat. See my next update.
R-Jackson is offline   Reply With Quote
Old 12-09-2022, 04:44 PM   #6
Junior Member
 
Join Date: Aug 2021
Posts: 7
Question

Thermostat update.

The HP and thermostat have been off for 2 days. Last night I heard the HP start up and run for some time (30 minutes?). When I got up the thermostat was showing the room temperature and the set point was 72. I increased the set point and the display temporarily showed the new set point and then reverted back to the room temp. Normally with in a second the compressor and fan will fire up. Today only a click, display goes blank and then displays 2 zeros and then reports the room temp again. The set point has changed back to 72. Looks like the thermostat was re-setting. This happens no matter if I select electric heat, heat or cool. I did this a couple of times and now there is no display on the thermostat. We have had nothing but rain here in Oregon for the last few days. just wondering if it could be WX related. Thanks
R-Jackson is offline   Reply With Quote
Old 12-10-2022, 04:28 AM   #7
Senior Member
 
triplewide's Avatar
 
Join Date: Mar 2015
Location: Greensboro, NC
Posts: 2,390
if you have 12 volts to the thermostat and the thermostat display is not lit up it may be the thermostat is bad. Still could be the connection MrMark52 referred to though. You would need to check for power at the thermostat when the display is off. A loose connection in the wiring at the HP could produce the intermittent thermostat operation as well.


To access the wiring at the heat pump you will need to remove the entire ceiling assembly. This could be an intake/distribution grill with filter(s) or just a large filter if duct only distribution.


This video may help: About 4 min in he shows install of ceiling grill.



__________________
1998 Min Winnie, 2000 Winbago Journey, 2015 ACE 29.3
2016 Thor Miramar 34.2
triplewide is offline   Reply With Quote
Old 12-10-2022, 08:23 AM   #8
Senior Member
 
Join Date: Aug 2019
Location: Eastern outskirts of Dallas, TX
Posts: 2,629
I’m still inclined to think your having an intermittent electrical connection somewhere - it could be at the thermostat, in the wires between the thermostat and the unit, or in the unit.

And, yes - intermittent connections can be temperature dependent as a change in temperature can cause wire to expand and contract, therefore making and breaking connections. Each making and breaking of a connection when there is a load on it tends to worsen the connection thru carbonization (arcing and sparking that occurs within the connection).

Motorhome and RV A/C and heat pump units are notorious for failing wire connections. More often the higher current connections such as power the compressor or blower/fan motor.

It also is not uncommon for the very light gauge control wires used between the thermostat and the unit to break at the connection - or I’ve even pulled runs of thermostat control wire only to find there is an internal break somewhere along the the pulled length.

All of your comments point to any one of the above scenarios. You could have a bad thermostat, maybe something internal isn’t properly soldered or making connection. But the problem could just as easily be on or to the control board in the unit.

I’m not a believer in throwing parts at a unit to see what sticks (what makes it work) - locating and finding the cause of the operational issues your having are going to require a systematic methodology of troubleshooting to find the problem cause. Apparent intermittent problems tend to compound the difficulty and identification of/repair of the cause.

If you are competent enough to use a volt-ohm meter, or are willing to learn, we can teach you. You first need to have a meter in hand, and then you also need a copy of the electrical wiring diagram for your unit, and post it here, so we can walk you thru what to and how to test.
__________________
‘91 Ultrastar Champion‘02 Georgie Boy Landau 8.1l Workhorse
‘03 Jeep Wrangler TJ 2018 Jeep Wrangler JK toad
MrMark52 is offline   Reply With Quote
Old 12-13-2022, 06:02 PM   #9
Junior Member
 
Join Date: Aug 2021
Posts: 7
Thanks MrMark. The display is now blank, not showing anything. I have 12v at the red and blue terminals on the thermostat PC board, but only if I remove the fuse. If the fuse is installed I only read 3.5V. This has me puzzled. What I would like to do is manually short out the wires to start the furnace, AC and HP individually to ensure they are working, but am unsure which ones to use or know if this is even possible. I have posted some pictures of the thermostat and AC/HP with a chart showing the wiring to/from. There is an extra set of wires at the thermostat. Not sure where they come from but suspect some go to the furnace.
AC/HP 1 and 2 show the diagram for the AC/HP
Furnace/HP show the wire connection from each unit.
Thermostat shows the thermostat and wiring
Wires coming to the furnace (2 orange, red, White)going to someplace
Wires from thermostat (2 yellow, white, orange, red/purple)
one of the yellow wires is marked with a small piece of tape.

Keeping with the thought of a poor connection, I have re-set the spades at the AC/HP as well as re-twisted the wires with the wire nuts at the thermostat.

Any help you can provide would be greatly appreciated.
Attached Thumbnails
Click image for larger version

Name:	AC:HP-1.jpg
Views:	3
Size:	213.8 KB
ID:	382644   Click image for larger version

Name:	AC:HP-2.jpg
Views:	5
Size:	205.7 KB
ID:	382645  

Click image for larger version

Name:	Furnace:hp.jpg
Views:	5
Size:	55.7 KB
ID:	382646   Click image for larger version

Name:	Thermostat model.jpg
Views:	4
Size:	59.4 KB
ID:	382647  

Click image for larger version

Name:	thermostat wiring.jpg
Views:	4
Size:	156.9 KB
ID:	382648   Click image for larger version

Name:	thermostat.jpg
Views:	4
Size:	159.4 KB
ID:	382649  

Click image for larger version

Name:	Wires coming from wall to furnace.jpg
Views:	4
Size:	104.8 KB
ID:	382650   Click image for larger version

Name:	wires from thermostat to wall.jpg
Views:	3
Size:	93.4 KB
ID:	382651  

R-Jackson is offline   Reply With Quote
Old 12-14-2022, 02:59 AM   #10
Senior Member
 
Join Date: Aug 2019
Location: Eastern outskirts of Dallas, TX
Posts: 2,629
If you have 12vdc between the red and blue with a fuse in the thermostat removed - then it might be the stat has an internal short. This is assuming the fuse is inside of the thermostat.
I’m also assuming the thermostat display could also be blank whether the fuse is installed or not.

Disconnect and isolate the other wires from the thermostat.

Keep in mind the Blue should be -12vdc or ground and should be common to all control components. You could also look to it as a neutral or common and is apparently needed to power the internals of the thermostat.the loose Green or Gray to the Red.
Either that or the reverse where the Red is common and the thermostat switches the Blue or -12vdc.

That should leave you with the Wht/Blk, Green, Yellow, Gray, and White.

Wht/Blk when powered should shift the Reversing Valve(which switches the refrigerant circuiting to run as an A/C or as a Heat Pump. Powered is one function, not powered is the other).
Green should run the fan in High speed
Gray should run the fan in Low speed
Yellow should run the Compressor
White should run the furnace (it’s fan should operate thru it’s own control system).

You should then be able to touch the Gray or Green to the Red to get the fan to run high or low speed. Only touch one or the other, not both.
You could then add the yellow and hear the compressor come on. Depending on the unpowered logic of the reversing valve, youl feel either heating or cooling coming from the unit.
And then if you add the Wht/Blk, you should hear the reversing valve engage and the refrigerant “spew” as pressures equalize and reverse direction.
If the stat switches -12vdc, then you would touch wires to the Blie.

Or, you could just connect the Wht to the Red (or Blue) and hear the furnace fan come on (and if left connected long enough you’ll hear the burner light and heat come out of the vents). The fan will also run on its own for a minute or so after disconnecting.

If all that works, then you have a high resistance short in the thermostat - as evidenced by the voltage drop to 3.5vdc between the Blue and Red when the thermostat fuse is installed.

If it doesn’t work, and you still see 3.5vdc across Red and Blue when any one of those wires are connected - then the step-down transformer in the unit is likely at fault.

Bottom line thought to all of the above - when power sources are over-drawn, the current in the circuit goes up while the voltage goes down. If the current being drawn isn’t high enough, it won’t take out the fuse, nor will anything burn (or the smoke be let out).
__________________
‘91 Ultrastar Champion‘02 Georgie Boy Landau 8.1l Workhorse
‘03 Jeep Wrangler TJ 2018 Jeep Wrangler JK toad
MrMark52 is offline   Reply With Quote
Old 12-14-2022, 06:10 AM   #11
Senior Member
 
triplewide's Avatar
 
Join Date: Mar 2015
Location: Greensboro, NC
Posts: 2,390
I think your coach has two roof top units. If they are both HP's, you could swap thermostats. That would tell you if the problem is in the thermostat or somewhere in the wiring or roof top. Take pictures if you do this, make sure the wires end up on the same terminals. Mark wires if any two are same color.



Nice coach by the way.
__________________
1998 Min Winnie, 2000 Winbago Journey, 2015 ACE 29.3
2016 Thor Miramar 34.2
triplewide is offline   Reply With Quote
Old 12-21-2022, 07:10 PM   #12
Junior Member
 
Join Date: Aug 2021
Posts: 7
Another update

As suggested I have taken the thermostat with the blank display (front AC) and installed it in the other AC/HP unit in the coach (bedroom). Everything in the bedroom worked fine. I also took the control box from the front AC/HP unit and put it in the bedroom unit, again everything worked. I have also confirmed that there are no breaks in the control wires for the front AC/HP unit. I also noticed that the bedroom thermostat (the one that is working) shows only 3½ volts at the power terminals with the fuse installed. Interesting.

Looks like the only thing left to check is the AC/HP unit itself. I'll wait for the rain to subside before I venture up on the roof.

Thanks
R-Jackson is offline   Reply With Quote
Old 12-22-2022, 03:41 AM   #13
Senior Member
 
triplewide's Avatar
 
Join Date: Mar 2015
Location: Greensboro, NC
Posts: 2,390
Never would have thought the roof unit would cause those symptoms at the thermostat. Good luck with the fix.
__________________
1998 Min Winnie, 2000 Winbago Journey, 2015 ACE 29.3
2016 Thor Miramar 34.2
triplewide is offline   Reply With Quote
Old 12-22-2022, 04:55 AM   #14
Senior Member
 
Join Date: Aug 2019
Location: Eastern outskirts of Dallas, TX
Posts: 2,629
Weird
__________________
‘91 Ultrastar Champion‘02 Georgie Boy Landau 8.1l Workhorse
‘03 Jeep Wrangler TJ 2018 Jeep Wrangler JK toad
MrMark52 is offline   Reply With Quote
Reply

Tags
heat, heat pump, pump, tuscany



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tuscany, roof top heat pump/AC Jim bob S. Class A Motorhome Discussions 5 08-04-2021 09:55 PM
Intermittent problem with my Coleman Mach 8 15K heat pump mrschwarz RV Systems & Appliances 2 07-25-2021 12:02 AM
Dometic Heat Pump to No Heat Pump Memphisbobby Newmar Owner's Forum 5 03-07-2021 07:07 AM
Air conditioner/heat pump intermittent Chuckboehme Tiffin Owner's Forum 7 03-06-2015 09:54 PM
To heat pump or not heat pump Bruce and Jenna Excel Owner's Forum 17 04-15-2009 11:20 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 04:03 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.