750mv vs 12v Thermostat Question UPDATE 2

One question
Do you not have. Or not use the battery disconnect switch in the RV

Or just pull the heater fuse in the 12v fuses panel

Well as usual CTC "tech" support is WRONG! It is a simple 2 wire stat. It is battery powered and all it does is open and close the contact, just like the old analog stat.the one in your link is the one I would have suggested, and is very similar to the Garrison that I bought at CTC last year and it controls the furnace just fine. No more guessing what temp you have actually set.
And the On/Off switch is built right in.

Sometimes the on/off switch is built into the slider. Moving it past the lowest official setting engages a cam or similar that keeps the contacts open.

I second Old-Biscuit's suggestion of a digital thermostat. Amazon sells This basic LUX branded one for under $20 that looks halfway decent to me (and apparently has adjustable temperature swing settings).

Digital ones have the advantage of not being susceptible to erratic operation when bouncing around, such as when driving on the road.

This digital one says no to 12v--scroll down to the questions--one guy asked about 12v.

http://www.canadiantire.ca/en/pdp/honey-non-programmable-thermostat-0529214p.html#spc

Answer says it is for "24v" but not for Direct Voltage. What's that supposed to mean?

Old-Biscuit wrote:
Why not go with a digital mode vs those analog manual slider control types?

Digital heat only roughly $27 at that Canadian Tire website.
And more accurate temp control

Shouldn't need to add an ON/OFF switch. T-stat can be turned OFF



IS old t-stat not working.....or is issue with furnace?
Connecting the two wires together will make furnace run IF t-stat is bad.
If furnace does NOT run when the two wires are connected then Furnace has problem

The furnace runs properly but the thermostat does not control the heat properly, so it is the thermostat that needs replacing for sure.

Don't mind digital, don't need programmable, but mainly trying to get a simple manual thermostat that does not have the bubble level and that works with the two 12v wires.

Some do not have an on-off switch apparently. The old one there now has a switch, but if you leave it "on" and turn the temp right down, and it is colder out than that, the furnace will stay on trying to get the temp up to that lowest number. So I can see from that why you should have an on-off switch.

Why not go with a digital mode vs those analog manual slider control types?

Digital heat only roughly $27 at that Canadian Tire website.
And more accurate temp control

Shouldn't need to add an ON/OFF switch. T-stat can be turned OFF



IS old t-stat not working.....or is issue with furnace?
Connecting the two wires together will make furnace run IF t-stat is bad.
If furnace does NOT run when the two wires are connected then Furnace has problem

There are three types of thermostats
one uses a mechanical make/break switch. You can see the contacts open and close. A small magnet provides some Difference between make and break temps
ACE Hardware (As I recall) or True Value (If not ace) sells one for 20 bucks

These work on both 750MV 12 volt DC and 24 volt AC, all the same it does not care.. It also does not need to be perfectly level making it ideal for RV use.

The second has a liquid (Mercury) Filled capsule on the end of a spring, the weight of the Mercury (liquid metal) provides the difference between Make and Break.. Like the above it works on all systems. UNLIKE the above it must be leveled else the settings will be off.. I do not recommend for RV use

The third is Electronic. This type is system specific, I do not recommend.