Help!

[Pete19762018]

Before I go any further I got on here to ask for help. My Coleman Mach thermostat quit working and upon replacing the thermostat with the one I bought at lowes, I came to a brick wall and have two wires in not sure what to do. I see every rv wiring could be different. I do not care about hi-low switch at this time. Thanks in advance for any info. 06 Laredo.

[chuckster57]

Welcome to the forum

Your Coleman Mach thermostat is 12VDC, Is the replacement 12V?

[Pete19762018]

No it is 24 Voly, but I was told the 12Volt would ?

[chuckster57]

I havent had a 24V thermostat work in a 12V system, Thats why I asked. Whats wrong with your Coleman Mach thermostat?

[Pete19762018]

The Coleman Mach had just quit working, AC nor Furnace.

[chuckster57]

Model # of thermostat?

[NH_Bulldog]

The thermostat runs to a control board in the AC unit, which in turn also runs the furnace. My guess is that the thermostat is fine but your control board may have failed, and/or something else is amiss in the rooftop unit.

[chuckster57]

Depending on which model thermostat, there is most likely a flowchart to troubleshoot it.

[Pete19762018]

I have RTH111 series.

[chuckster57]

Which Coleman Mach thermostat. I just took one of those out of an older 5er, so I know it won’t work in a 12V system.

[meaz93*]

A couple years ago I changed out the stock Coleman unit to a Honey Well. Works perfect.
Maybe these pics will help you.

[chuckster57]

Originally Posted by meaz93*

A couple years ago I changed out the stock Coleman unit to a Honey Well. Works perfect.
Maybe these pics will help you. Attachment 38365Attachment 38366Attachment 38367Attachment 38368

That’s not the thermostat PO bought. Maybe he should exchange it.

[meaz93*]

Not sure why OP can't make his work?.....thought maybe the wiring sequence to the HoneyWell would be of help?
Well....at least this unit is a for sure[emoji106]

[Pete19762018]

The rth was cheaply made so I took it back and got the T2. They didn't have the 5000, I noticed I have only 6.5 cold at the red and white wire to thermostat. I have 12 or 13.3 everywhere else. I did replace the manual breaker odd the battery last yr. The rubber boot wasn't the best so I melted glue over it some. That glue has wore off exposing wire connection, wonder if that's where I'm losing voltage? I'm going out shortly and replacing that breaker again just because I have a new one. Clean wires etc. Losing voltage somewhere, where does the red wire go off thermostat?

[meaz93*]

@Pete19762018 ....sorry about that pic with the red wire hanging?
I went out to my rig and looked at my old Coleman vs the HW 5000.
On my Coleman the 12v power wire was tapped with a yellow wire from the factory.
Heres the wiring behind the HW.

[Pete19762018]

I discovered I only have 6.5V at the thermostat. Last year I changed the automatic breaker at the battery, I'm wondering if that is where I'm losing voltage because the rubber boot that covers the connection was torn and I covered it with glue at that time, well the elements got the best of it and I see green and white corrosion on the wires, got a new boot and fixing that today. Hopefully I'll once again have 12 V. Also when I test red wire at thermostat, if it reads 11v for example I watch the voltage quickly drop all the way back down to 6.....volts. weird...

[flrtrader]

[May I ask if you would in more detail explain how you switched this? I have the same coleman thermostat and it has a wide swing when the heat or air comes on. I wanted to put digital in but a tech told me these were not like homes and I would have to switch something on the main board to switch to digital. If you like you can PM me.

God Bless

Keith



QUOTE=meaz93*;486547]A couple years ago I changed out the stock Coleman unit to a Honey Well. Works perfect.
Maybe these pics will help you. Attachment 38365Attachment 38366Attachment 38367Attachment 38368[/QUOTE]

[bbells]

Make sure you are getting 12v on your input wires before doing anything else. Could just be the inline fuse.

[apachewolf]

I have had the same problem with the original thermostat. I replaced it with a HONEYWELL RTH2300/RTH221 SERIES. It runs on 2 AAA batteries and has 4 individual setting per day. It is very easy to install and the price was around $ 20.00 at Walmart. It does not have a switch for the high/low fan setting, I used to high and it works great I handles both AC and the furnace.

Happy camping!

[Pete19762018]

I am dealing with more than one problem, I got the AC to work but not the furnace yet. But I got a couple things going on here. I will update today.