Adjustable Water Heater Thermostat

Consider installing fixtures with a single handle to better regulate the water temp.

I installed the adjustable thermostat on our water heater but still found the water to be too hot. Holding the thermostat body firmly, I forced the set screw counter-clockwise and was able to get the thermostat down to about 105 degrees.

We are able to take a shower with minimal or no use of cold water. We dry camp mostly and are in a water saving mode, so do not want the unlimited shower (at least in the camper).

The snap disc t-stats that Atwood uses on their DSI (Electronic Ignition) water heaters are pre-set.
Normal t-stat is 140*F and the ECO (energy cut off....high temp) is 180*F

The adjustable replacement for the normal can be set for 110*F to 150*F
The mounting bracket is flimsy cheapo thin metal that slips under lip of opening where disc goes and the spring is light weight. It does work but could be a better design.
It is open to exposure and can get corroded ---then break when attempting to make any adjustment.

Reason for the high temp normal (140*F) Atwood uses is to get more hot water out of the small tank size (6 or 10 gallon)
End user controls temp at faucet by mixing cold/hot together

Suburban uses 130*F and has an optional 120*F set (t-stats come in a combined set normal/ECO connected to each other) so can't be interchanged with Atwood

The Atwood 91470 t-stat is 120*F (Atwood FINALLY offering a lower preset)

Only thing is with snap disc preset they have a range from closed to open typically 30*F

The 140*F OEM doesn't reclose until 110*F for reheating so the 120*F one might not reclose until 90*F.
If that is the case you will notice large temp swings in water from WH
Mildly hot to warm.


YES the t-stats are low voltage ever since 2004 when Atwood changed to circuit board controlled with front mounted t-stats
And the terminals on normal are smaller than the ones on ECO so they aren't mixed up when installing

My Atwood has an adjustment, so did my older Atwood. I thought they all did.

But yes, if you get it hotter, it'll last a little longer.

My 2016 Coleman came with the the old style that Uses a pilot light, and has an adjustable thermostat. A little more trouble to light but I much prefer this as I can control the water temp to suit us. It uses very little propane to keep the water hot.

Makes sense to me too. Having 2 people needing to shower in the morning - the more hot water available the better. But - I don't have little ones taking baths anymore - so I understand the concern.

jwmII wrote:

midnightsadie wrote:
I never could understand why they make it that way, I have no answer for you.

They make it that way so you have to use more cold water to temper the hot therefore making the hot water go further so you can get a little longer shower with a 6 gallon tank. The bad thing is the water is at or near scalding and must be carefully controlled. Around children especially.

Makes sense to me....

midnightsadie wrote:
I never could understand why they make it that way, I have no answer for you.

They make it that way so you have to use more cold water to temper the hot therefore making the hot water go further so you can get a little longer shower with a 6 gallon tank. The bad thing is the water is at or near scalding and must be carefully controlled. Around children especially.

Good feedback. I notice some sites list the 91470 as 120 degree, others as 130 degree. I was able to read the labeling on one picture and it said L130, which I think means 130 degrees.

I'd really like to take it down to 110-115. I don't see why I couldn't use a universal snap button 110 or 115 normally closed thermostat. It's definitely low voltage and low current on my propane only water heater, besides the high temp cutoff (150 degrees?) would still be in place.

I installed that thermostat. I really didn't notice a big swing in water temp versus ambient temps. Last time out temps ranged from high-50s during the day and low-30s at night. The water temp was definitely an improvement over the original thermostat, though you still need to keep it adjusted on the low side (lowest is "A" and it goes up from there). I think I have mine on "C". It still pretty hot - hotter than my home HW - but much better than the scalding hot water I used to have.

When installing it, you have to make sure you get the spring installed properly so it's fairly tight against the tank. I also replaced the black insulation stuff around both the thermostat and high-temp cutout at the same time.