Aquahot question

[Flyinhy]

Well, if it isn't one thing it's another. My aquahot has run like a champ all winter long. 2 days ago I noticed the water was unusually hot. So I opened the lower bay and steam rolled out. The overflow was bubbling and the tank was roughly 5 gal low. I filled it up and turned off the diesel side and only ran the electric element. This morning I opened the bay again and ......same thing, steam coming out and everything in that bay is slightly wet. I have a good idea the problem is one of the thermostats has gone bad. Has anyone else had this happen? It's about time to do another service anyways......

[Dr4Film]

Sounds like one or both of the control thermostats have failed along with both HIGH Limit Thermostats have failed too.

The control thermostats, one for the diesel and one for the electric assist are to maintain proper boiler fluid temperature. Then the HIGH Limit thermostats are there to prevent either of the two heating systems from overheating the boiler fluid.

[vito.a]

Are you using propylene glycol boiler fluid mixed with distilled water?

I agree with Richard.  You can use an ohm meter to test each thermostat.  The thermostat should open when the boiler reaches the required temperature.  

There are four thermostats in the system behind a small access panel in the firewall. The cover is held on with two screws.  

I think I would replace all four thermostats.  After two fail, the others are not far behind.  

Until your new parts get here you can still use the diesel system.  Just run it for 15-20 min and then turn it off.  You can do the same with the electrical side, but let it run for an hour and then turn it off.  

Chemworld has the best price on boiler fluid.  

https://www.chemworld.com/Boiler-Antifreeze-s/1994.htm

Edited April 11, 2023 by vito.a

[Flyinhy]

I went ahead and just ordered both ac thermostats.  Like yall said , I'll just heat with the diesel side when I need it until my parts come. A funny side note. I've owned this coach for almost 2 years and I never could find my bay heater. I just happened to look up and out of the corner of my eye I spotted the fan over the center of the aquahot unit. Completely hidden! Whenever I get enough time off I need to go back through my unit and replace bearings in the burner. Too many projects to going on right now to do that. Thanks for all the advise guys....