Community Forums

Terry W · 05-21-2016, 08:36 AM

I believe I read in a post on here that I can use the engine heat through the HH to provide coach heat while traveling. Is this correct? If so how do I accomplish this? Getting ready to hit the road and it may come in handy.

Thanks, Terry

tom chelbana · 05-21-2016, 11:37 AM

Terry Yes you can heat your coach with Hydro-Hot as long as you have engine assist if you don't want to run diesel heater. Engine assist is when you have heater hoses running from engine to Hydro-Hot system. With out have to look you would know if you have hot water as soon as you get to a camp ground from the hoses run from engine that would have heated your Hydro-Hot unit. Most do have engine assist but not all. With this then you only need to use diesel burner to heat the water first thing in the morning if you want to use at the start of the trip. After you have driven for 15 minutes you won't need your diesel burner because the Hydro-Hot will be keep hot from engine which will then keep the coach warm too. You can still use your dash heater also. We have a Essex coach and we didn't know this for the first 5 years of owning it. Have never seen this in print.

Ron_H · 05-21-2016, 01:22 PM

As Tom said, if your HydroHot boiler lines are connected to your engine you have heat available while traveling.

Set your thermostat to "FURNACE" and turn on the fans using the FAN button on your HydroHot control panel.

Essentially, you have free heat.

DrDaveMA · 05-21-2016, 02:28 PM

Terry, Alpines with HH were built with the "Engine Preheat" function. That means the engine cooling lines run through the HH, all you have to do is turn on the thermostat, set the temp you want, once the engine comes up to temp it circulates hot water through the HH, heats the coils and you are all set, we drive with it on all the time. That is also the function you enable to preheat the engine, you turn on the "Preheat Engine" switch, the HH heats up, then circulates hot water to the engine.

Dudley do-right · 05-24-2016, 05:51 PM

By the way, Dr. Dave, do you know by chance, if the temperature of the potable hot water can be ajusted? I have looked at the nomenclature that came with the coach, (Hydro-Hot booklet) and it says nothing about being able to regulate the potable hot water. On our 2007 36FDDS, the water was always smokin' hot, however, the water in the 2006 40MDTS we just traded for, while acceptably hot, we would prefer that it be a little hotter, but don't know how to go about it. any suggestions?
Dudley, (Dudley Do-Right)
2006 40MDTS Apex
PS You may have seen my post about changing the zone pump that controls the heat exchanger for the hot water.. that improved our hot water supply a lot, just not to the degree we expected.

Janet and Todd · 05-24-2016, 06:07 PM

Go here and download the service manual for your unit:

Aqua-Hot - Manuals

DrDaveMA · 05-24-2016, 06:24 PM

WRV put in n a HWH model that has an adjustable mixer valve on the domestic hot water output. You just have to be able to reach it, some floor plans are easier than others. On our 38 FDTS you have to take out one of the WRV carpeted dividers, then you have full access to both the HWH and the charger/inverter, on others you need to cut the floor.

Dudley do-right · 06-04-2016, 08:18 AM

Hey Dr. Dave, I read your posts, re: mixing valve, and yours and another post put me on the track. I downloaded the manual for our unit, and there is a tempering valve on the back of the Hydro-Hot. Problem is, it's virtually impossible to get to. Possibly could get to it from topside, in our 40MDTS the vanity w/elect. panels under, seems to be directly over the back of the HH with slide in, and with slide out, tile floor. Looks like a no-can-do, unless I can find somebody with reeeeal long arms. Thanks, Dudley

DrDaveMA · 06-04-2016, 07:57 PM

Dudley, there have been several posts about opening a HH access hole from underneath, do a search to get recommendations on how to do it. Fortunately for me, with the 38' FDTS, access is by removing a divider panel in the basement, reaching past the inverter. I have seen pictures of other models that are not so easy. Remember that you have to be careful cutting access, it is very easy to hit something inadvertently. Also be sure to reseal the opening after you are done.