Coleman Mach thermostat wide offset

[Barchetta]

Is it normal to have a 5 degree temp offset? Seems like my ac kicks in at 79 and drops to about 74 or even lower. I cant seem to find the manual online for the t stat.

[RoadrunnerII]

Yep
On the analog thermostat!
Go buy the digital version. We did
Holds the temp much closer.

RoadrunnerII

[Barchetta]

Originally Posted by RoadrunnerII

Yep
On the analog thermostat!
Go buy the digital version. We did
Holds the temp much closer.

RoadrunnerII

I dont suppose a household stat will work.

[twinboat]

I installed a household digital T stat in both my RVs.

Goggle how, and its all explained.

The digital T stat runs on AAA batteries so some wires are left off. They don't have the Hi/Low fan switch but I just chose Hi. Others add a tiny switch. Its talked about in the online instructions.

Now I have a 2 degree swing, and that's adjustable.

[jdpm]

Originally Posted by Barchetta

Is it normal to have a 5 degree temp offset? Seems like my ac kicks in at 79 and drops to about 74 or even lower. I cant seem to find the manual online for the t stat.

I have 2 of them. Both cycle on and off one degree either way of the set temperature.

[chunker]

RVs lose their heat/cool so quickly because of being poorly insulated that if the duty cycle of the thermostat was closer like a typical residential type you likely would be experiencing an almost immediate re-energize of the heat/cool cycle. With a heat pump there is a built in delay before the compressor can restart to avoid excess head pressure and failure. I think regular a/c does the same. With propane heat there is a cool down cycle that runs the fan after the burner extinguishes. I agree it can be annoying but we have adapted and I don't plan any changes or attempted adjustments.

[Barchetta]

Originally Posted by drwwicks

RVs lose their heat/cool so quickly because of being poorly insulated that if the duty cycle of the thermostat was closer like a typical residential type you likely would be experiencing an almost immediate re-energize of the heat/cool cycle. With a heat pump there is a built in delay before the compressor can restart to avoid excess head pressure and failure. I think regular a/c does the same. With propane heat there is a cool down cycle that runs the fan after the burner extinguishes. I agree it can be annoying but we have adapted and I don't plan any changes or attempted adjustments.

After considering this thermostat carefully I agree with your assessment.

Chances of a "freeze up" would be higher too if the system cycled more often. So Im going to leave as is. Its no big deal really other than getting a little warm or a little chilly depending where you set it for a few minutes.

I did some maintenance and found my evaporator caked with gunk. Vacumed a lot of it off but have some more work to do in that regard.

The filter is terrible on my unit. Not sure if there is a reason for that. Im hesitant to "modify" these days.. engineers are not dummies.

[chunker]

Originally Posted by Barchetta

After considering this thermostat carefully I agree with your assessment.

Chances of a "freeze up" would be higher too if the system cycled more often. So Im going to leave as is. Its no big deal really other than getting a little warm or a little chilly depending where you set it for a few minutes.

I did some maintenance and found my evaporator caked with gunk. Vacumed a lot of it off but have some more work to do in that regard.

The filter is terrible on my unit. Not sure if there is a reason for that. Im hesitant to "modify" these days.. engineers are not dummies.

The engineers "might" not be dummies but RV builders are. You didn't say what RV or where the filters are but RV builders do stuff without regard to whether it works, or works well, at all. Just that it "fits". Example my GF has a Crusader 5th wheel and the main a/c is fully ducted, no ceiling plate, 2 remote small intake filters to the side. Nice in theory, bad in practice as the filters are difficult to get to, not efficient. Most ceiling a/c have the filter in the ceiling plate and it's not much more than a piece of foam. Generally speaking that works OK since the ceiling doesn't get much dirt go by. My motorhome has a residential style 2T heat pump and the filter is near floor level. It uses a regular home style filter and because of it's location, gets dirty quicker and changed more often.

In my opinion if you improve the filter using common sense you will be fine. Common sense generally isn't used or applied in RV manufacturing ordering.