How hot should hot water be? Dometic hot water heater question

[alias100]

My wife and I have a new 22RBE with a Dometic Model WH-6GEA water heater. On a week long trip last week it worked fine for 4 days, then we noticed a burning rubber smell when we opened the drawer to the bathroom cabinet over the water heater. We only ran the water heater when we needed hot water, so an hour or so morning and evening. It worked that night and the next, but after a shower it quit working. I figured out it was the Thermal Cutoff that was the problem. Today I replaced the Thermal Cutoff and it fired right up on gas. It kept running for quite a while so I checked the water temp and I could not keep my hands under the water, just too hot. I used a thermometer and the water coming out of the bathroom sink was 152 degrees Fahrenheit. That seems too hot so I shut if down.

- Is this too hot, or is it normal? If showering at that temp you could easily get scalded.
- It looks like there is no temp adjustment, so should I look at replacing the Thermostat Assembly, something like this? https://www.amazon.com/dp/B00OVBJX3Y...v_ov_lig_dp_it

I am guessing that the thermostats are not functioning so the gas stayed on and that over heated the Thermal Cutoff and caused the burning rubber smell (but I am wrong on a regular basis ).
Any other suggestions or questions?

Thanks

[Redapple63]

The code varies, but the max hwh temp is 140 deg f.

Many prefer 120-130 deg.

If your is at 154, it’s too hot.

Thanks,
Bill

[Jerryr]

The thermostat is fixed at 140 degree setting.

Here’s a set with the therm and eco https://pantherrvproducts.com/dometi...ture-shut-off/

[SolarPoweredRV]

The code varies, but the max hwh temp is 140 deg f.

Many prefer 120-130 deg.

If your is at 154, it’s too hot.

Thanks,
Bill

I agree with Red Apple63

[Ynot4me2]

I haven't measured ours yet but it's real hot. To the point where you have to be real careful.

Sent from my SM-P610 using Tapatalk

[Scott'n'Wendy]

Our house HWH can be set from 120 to 140. Some RV HWH are designed to run around 160 along with a mix valve which drops it to a lower temp. A failed mixing valve could cause your issue. I'm not familiar enough with GD plumbing to know if they ever used mixing valves. My previous trailer had one...and it failed.
OR, if a HWH that was intended to be used with a mixing valve was installed by mistake?

On edit...never mind. No mixing valves that I could find.

If it were me I would be finding the manufacturer's name and model number and finding out the temp specs. You got a bag of manuals with the trailer. Look in there. If a part was needed, I'd be calling GD first.

[IBEW Sparky]

@alias100

Replace both the ECO and the T-stat together with the correct rated parts, double check your wiring, and also make 100% sure that both devices are being held firmly against the water tank. That is the only way that they get a true temperature reading.

[alias100]

I called Dometic and was told that the gas should shut off at 180 degrees. I don't think the person I spoke with understood that there are 2 thermostats, the regular one and the ECO (Emergency Cut Off) and that the ECO is just a failsafe. I have ordered a replacement thermostat. I called GD and was told that there is no mixing valve in the 22RBE so it does seem to be heating to too high a temperature, but they will reimburse me for the replacement parts.
Thanks for all the replies and I will update if the replacement parts fix the issue.

[sande005]

Depends on brand, but many do not have a temp adjustment nor a mix valve, and run scalding hot. True for the Atwoods I had in the old Jayco, and now in the 2670MK. Gotta do your own mixing in the shower, and be careful for the surge of hot when you turn the water back on. Atwood does sell an adjustable thermo that can be an upgrade. But with only 6 gal of water and not a super fast recovery, it may not be the answer.

[alias100]

I am the person who started this thread. Looks like it was a bad (or off) thermostat. I replaced it with a new one and when the gas turned off the water measured at 148.2 Fahrenheit. I used some water, the gas kicked on and when it shut off the water was the same as before. Still a bit hot for my taste but better than before.
As a test I put a multimeter on the old thermostat and got conductivity at room temp, but when I put it in a pan with a 1/4" of very hot water I did not get conductivity. Put it in a small amount of cold water, got conductivity again. Looks like it works, but triggers at too high a temp. I didn't have the right equipment (or motivation) to do a more thorough test to find the trigger temp.
Thanks for all the comments.