Hydro hot HHE-500-09M - 12 VDC Fresh Water Tank Thermostat (bay heating) ~40 deg oper

[Any ole Joe]

As winter approaches, I am trying to clarify the Hydro hot HHE-500-09M - 12 VDC Fresh Water Tank Thermostat (bay heating) ~40 deg operation. I understand the furnace zone operation, but could not find documentation on the bay heating and which, if any, zone controls it. From reading comments, it appears if you turn on either the burner or 110v overhead switch, it will automatically come on below 40 degrees. I called aqua hot and they said this was a Newmar specific question, so I called Newmar customer service and was told the burner had to be on and the furnace selected? When I asked which zone, she recanted and said just the burner switch and she could not advise on 110v operations? I normally have excellent support from the mother ship, but this rep was not polite or knowledgeable… told me if I wanted more information I would have to get a tech to call their tech… then she hung up on me 🤨We have an 07 Essex with a Hydro hot HHE-500-09M - 12 VDC. Any help on how to turn on the bay heating for storage would be greatly appreciated (documentation would be awesome!

[charlie hamby]

It runs when you run the bathrooms zone.Should be a switch in half bath to turn on.

[Wschep]

I have a 2008 Essex, with an Oasis Heater, however I believe the wiring would be close to the same as I believe that you have eplex as I do, However I don't believe ePlex has any bearing on this circuit as its directly from the battery to the water bay switch then directly to the oasis heater.

My oasis shows each AC zone unit sending a heat signal to the oasis heater, however the water bay heater runs on a separate control thermostat that is simply a open/close switch based on temperature. I don't believe it has any other control and operates anytime its below 40 degrees.

I have attached my wiring for the Oasis which shows the water bay circuit.

You can see that in mine the circuit is called Thermostat 5 and Fan circuit 5. One is to start the heater (Oasis) and the fan circuit is to start the fan running over the heater coil in the water bay.

Hope this helps

[Any ole Joe]

Thanks you both so much for the information! I will now compare this to our coach. Two things I don’t understand (may be missing it). I don’t see the ½ bath on the wiring diagram. We have one and I thought it was a fan switch only. Second, zone 1 doesn’t look like zone 4 on the diagram. I thought zone 1 had to be on “furnace” to work? With a thermostat direct line to the battery, seems the bay heating would come on automatically, but the fan requires Oasis to start. Would this be the 1/2 bath switch? Again, thanks a bunch… sometimes I am just thick headed .

[Wschep]

I have attached my multi page notes that I made on my system,

On Page 2 you will see the 1/2 bath switch. Both bathrooms are controlled together. When you turn on the 1/2 switch it simply turns on the fan in the 1/2 bath. the Oasis heating cooling pump for the bathrooms runs anytime the full bath calls for heat, the fan in the 1/2 bath only comes on when you have the switch in the half bath on.

See if this document answers any more of your questions

The written notes on them are for my reference

[Wschep]

Here's the Document for the previous post

[Wschep]

When the wet bay thermostat (Thermostat 5) closes, it send an input to the oasis to start heating, The oasis then sends an output on Fan 5 circuit to start the fan on the wet bay fan heating coil to blow air over the heating coil in the wet bay.

[Any ole Joe]

Originally Posted by Wschep

When the wet bay thermostat (Thermostat 5) closes, it send an input to the oasis to start heating, The oasis then sends an output on Fan 5 circuit to start the fan on the wet bay fan heating coil to blow air over the heating coil in the wet bay.

This makes perfect sense now! Thermostat 5 works independently of other zones and once closed, only needs to know whether to use 110v or the burner as the source of heat which is provided by the overhead switches.

[Wschep]

Originally Posted by Any ole Joe

This makes perfect sense now! Thermostat 5 works independently of other zones and once closed, only needs to know whether to use 110v or the burner as the source of heat which is provided by the overhead switches.

Yes, you figured it out. Good luck with your Essex, hoping to run ours 10 more years

[Any ole Joe]

Thanks again for “step by step” solution! Awesome! We love our 07 Essex, it has been a 6 year project and we love it. Not sure I would trade it for a new one. Waxing this week, decided to use scaffolding for the top half… looking good. Best of luck with your 08 too!