Aqua hot and Coach heat

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- Winterizing a coach {split from Re: Aqua hot and Coach heat]

Aqua hot and Coach heat

September 24, 2021, 01:30:37 pm

I have a question about how the AH system actually heats the coach in zones. We are planning to soon do a bit of traveling, and as the seasons they are a changing, want to fully understand how the system works, so if something fails I know where to look.

I understand the flow design of the system, but supposedly each zone will call for warm water when needed. I only see one thermostat in my rig that being in the bathroom. What in the system tells each zone to open up and provide flow? are there temp sensors strategically placed throughout the coach and I have yet to discover those?

Any info appreciated.

Re: Aqua hot and Coach heat

Reply #1 – September 24, 2021, 01:41:14 pm

On mine the thermostat at the front of the coach does the air
conditioners, the heat pump and the heat from the Aqua-hot.
There is a temp sensor in the bedroom that is controlled from the
front thermostat. I need to cycle through the controls to get what
I want. In the front thermostat there is zone one which is the front
area and zone 2 is the bedroom area. The termostat in the bathroom
is just for the bathroom. There is also a thermostat in the right side of
the wet bay to keep the wet bay from freezing.

Re: Aqua hot and Coach heat

Reply #2 – September 24, 2021, 01:50:59 pm

Mine is exactly as OG described above.

Don't you have one of these in the main salon?

Re: Aqua hot and Coach heat

Reply #3 – September 24, 2021, 02:28:04 pm

Mine works as mentioned above. Look just behind the drivers' area, on the wall. Maybe yours is even missing? How do you control the AC units now?

Re: Aqua hot and Coach heat

Reply #4 – September 24, 2021, 04:00:07 pm

Mike, for interior heating when outside temps are below 50 degrees, turn on the diesel burner. If plugged in to shore power, turn on the electric element too. Turn on the diesel burner any time you are using lots of hot water, shower for example.

Re: Aqua hot and Coach heat

Reply #5 – September 24, 2021, 07:02:15 pm

On your thermostat for the ac's if you cycle through them you should see furnace as one of the options. Select furnace and that is how the zone is turned on.

Re: Aqua hot and Coach heat

Reply #6 – September 24, 2021, 09:36:31 pm

Guys thanks for all the input. Yes I have a dometic controller behind my driver seat that controls the zone 1-2 ac systems, so far I have only run the AC units for climate control. I have new roof units that are also heat pumps. Now that you mention it I do recall zone settings for Furnace and HP. I guess when I saw the simple old style stat for the bathroom, I was looking for what else controls the zones and overlooked the dometic controller.

Rudy, yeah I saw where you replied on that topic to a person wondering why their hot water was puny, was good to know that tidbit.

OG when you mention a wet bay thermostat, are you referring to a small metal rotational setting device? I was wondering what that was. I have not researched it yet but was sort of wondering what most folks due to winterize. I m guessing keeping the wet bay from freezing is more designed for those that travel during extreme cold vs winterizing protection. We personally like traveling when its cooler but not Frozen, was thinking just like our 2nd home in the mountains, I would drain all liquids and use the pink stuff in all the traps.

Re: Aqua hot and Coach heat

Reply #7 – September 24, 2021, 09:45:49 pm

If I recall, The AH zone pump for the water pump area gets it's power when the bathroom thermostat is turned on. But the temp in the wet bay is controlled by the round dial in the bay. If I recalled incorrectly, someone will be along to correct me.

It's been my observation that my bays stay pretty warm anytime the AH is running in all but the coldest weather. But then we go south and don't see a lot of cold. Just cool.

Re: Aqua hot and Coach heat

Reply #8 – September 24, 2021, 10:48:11 pm

Quote from: bigdog – September 24, 2021, 09:45:49 pm

If I recall, The AH zone pump for the water pump area gets it's power when the bathroom thermostat is turned on. But the temp in the wet bay is controlled by the round dial in the bay. If I recalled incorrectly, someone will be along to correct me.

It's been my observation that my bays stay pretty warm anytime the AH is running in all but the coldest weather. But then we go south and don't see a lot of cold. Just cool.

I don't believe the bathroom thermostat has to be on for the basement heat to work, only the aquahot has to be on, diesel or electric or both, for the basement heat to work it works off this thermostat in the basement.. Rudy can correct me if I'm wrong...
The basement thermostat is in this pic.

Keith

Re: Aqua hot and Coach heat

Reply #9 – September 24, 2021, 11:11:07 pm

That's right Keith the wet bay thermostat controls the wet bay
temperature independent of the bathroom thermostat even then
though they use the same circulation pump.

Re: Aqua hot and Coach heat

Reply #10 – September 24, 2021, 11:36:10 pm

Quote from: oldguy – September 24, 2021, 11:11:07 pm

That's right Keith the wet bay thermostat controls the wet bay
temperature independent of the bathroom thermostat even then
though they use the same circulation pump.

Yes, That's kinda what I said. But unless the bathroom thermostat is at least POWERED ON even if set to minimum. The circulation pump won't run. At least that was my understanding.

Re: Aqua hot and Coach heat

Reply #11 – September 24, 2021, 11:56:28 pm

BD, either thermostat, bathroom or basement, will turn on the shared circulating pump. The bathroom thermostat does not need to be on for the basement thermostat to call for heat and turn on the circulating pump.

The basement thermostat has no off position. If your coach is being stored and the outside temps get cold enough it will turn on the circulating pump even if the heat sources (120v or diesel) are not on. The basement thermostat has three wires. I added an inline three wire connector and disconnect the thermostat while the coach is stored in cold weather (and winterized, of course).

Re: Aqua hot and Coach heat

Reply #12 – September 25, 2021, 12:03:32 am

Quote from: Roger & Susan in Home2 – September 24, 2021, 11:56:28 pm

BD, either thermostat, bathroom or basement, will turn on the shared circulating pump. The bathroom thermostat does not need to be on for the basement thermostat to call for heat and turn on the circulating pump.

Thanks for the correction Roger. It's been four years since I last stored the coach over the winter months. 👍

Re: Aqua hot and Coach heat

Reply #13 – September 25, 2021, 01:53:25 pm

Since the op's question has already been answered, I'll add my situation to it just to muddy the waters a bit.
When I switched out my dometic air conditioners I could not get my thermostat behind the driver's seat to control the aqua hot. I troubleshooted it with David from Las Vegas and with Rudy and no matter what we tried it would not work. So I got real familiar with the system. A ground signal is sent from the thermostat through the AC unit and down to some solenoids that are outside the aquahot that foretravel installed but then sends a signal into the alcohol to call for heat. For some reason I wasn't getting that signal from the thermostat and after calling the company I was told was take it to a authorized repair center which I wasn't able to do at the time. My solution which is worked for me in the last 18 months and 15,000 miles was to buy two dometic thermostats similar to the ones in the bathroom and wire it directly into the solenoids. With 12 volts. So I have the ability to run both the aqua hot and the heat pumps on the ACs.
I put one thermostat in the living room next to the jackknife sofa and the other one in the bedroom where the old TV used to be. That way I can control all three zones independently. It's a slider bar so it's not like I can just pick a temperature I just slide it until it comes on and then slide it back a little bit so when it gets cooler the heat will come on. If I get too warm I turn it down if I'm cold I turn it up a little. This works for me and while I'm still not sure why I wasn't getting that ground signal from the thermostat it doesn't matter anymore.
As far as winterizing I have not had to do that yet nor hope to ever have to but I would do as Michelle said and put the pink stuff through all the lines not just the traps. Why take the chance of rupturing a very expensive piece of equipment?
Currently in Nebraska heading up to South Dakota where I'll spend the next month and I expect that it will get fairly cool up there by November. I love my aqua Hot and I'm so glad that I have it.
Bob

Re: Aqua hot and Coach heat

Reply #14 – September 27, 2021, 09:17:18 am

Bob,

Thanks for that input, and not good to hear that yours is/was messed up. I ran my AH system yesterday for a few hours as it had not run in a while. I then tested both of my heating systems, Furnace/AH and the HP on the roof. Both did as they were supposed to. Very impressed by the amount of heat that the AH system put out. Surely did not realize that zone 1 ( front) would also put out through the defrost vents when Z1 is on. Figured that would only come from engine heat. So looks like all of ours is working as it is supposed to.

Still good to know what you had to do, as we never know what future issues might present itself, and alt options are always good to know about.

Mike.

Re: Aqua hot and Coach heat

Reply #15 – September 27, 2021, 09:30:52 pm

Just listened to our aqua hot go threw a compleat no load start up and shut down after about five minutes. So glad the service I finished on it last week is paying off. New capacitors in control box. New ignition unit and fuel nozzle. Kinda feel like a blind squirrel that found a nut. There was two capacitors in the control box that never would of made it threw the week. Both were leaking. All made possible by Rudy's fast response with the ignition unit. Thanks again. 44 degrees outside but toasty inside.
Scott and Kim

Re: Aqua hot and Coach heat

Reply #16 – September 27, 2021, 09:37:55 pm

Scott, guess I've been snoozing. Could you talk us through the cap replacement with pix, or point us to a thread that does? Thanx. Woody.

Quote from: dsd – September 27, 2021, 09:30:52 pm

Just listened to our aqua hot go threw a compleat no load start up and shut down after about five minutes. So glad the service I finished on it last week is paying off. New capacitors in control box. New ignition unit and fuel nozzle. Kinda feel like a blind squirrel that found a nut. There was two capacitors in the control box that never would of made it threw the week. Both were leaking. All made possible by Rudy's fast response with the ignition unit. Thanks again. 44 degrees outside but toasty inside.
Scott and Kim

Re: Aqua hot and Coach heat

Reply #17 – September 27, 2021, 09:46:34 pm

Quote from: Pyolet – September 27, 2021, 09:37:55 pm

Scott, guess I've been snoozing. Could you talk us through the cap replacement with pix, or point us to a thread that does? Thanx. Woody.

Webasto SG 1553/12v controller Aqua hot 431

Re: Aqua hot and Coach heat

Reply #18 – September 27, 2021, 09:51:30 pm

Reply #13 – 3 weeks ago
Quote from: David Bethard - 3 years ago
Depends on what the symptoms are. My only experience is with the older metal can version.

The electrolytic capacitors tend to fail as they age. The capacitors determine timing, I've had several that failed to stop the blower properly and cycled on/off. I've had success replacing the capacitors however other components can fail. A schematic of the circuit board would be great but no success finding one. On the older metal enclosed controllers the connector end can be pryed off and the ciucuit board slides out.

If you know a little about electronic circuits and you're handy soldering it may be worth trying. Cost of new controllers is ridiculous and they last 7 years or so. I have two controllers and replacing the capacitors fixed both of them.

Capacitors are available from Newark Electronics and they're cheap.

Controller Capacitors
2 ea 220 uf Axial 16VDC C1 & C3
1 ea 100 uf Radial 25V C4
1 ea 10 uf Axial 63V C2
1 ea 470 uf Radial 35V C5
1 ea 10 uf Axial 33V C6

So during initial inspection i noticed that the C2 and C6 are the same value at 10uf Axial 63v
Will order extra if anyone needs PM me
My unit was working good but since I'm changing the ignition unit this would be the other weak link. Proactively changing capacitors is good in my opinion. I know no one has touched them prior to 2007, so they are old and have been threw many summers.
Scott

Re: Aqua hot and Coach heat

Reply #19 – September 27, 2021, 10:00:49 pm

Woody it's not rocket science. Capacitors get old and fail. They sell different life rated and the best cost pennies more that that cheap. Soldering iron and a vacuum solder sucker from Amazon and it took longer to strip the silicone off than anything else. pop the top off and replace silicone used to seal it up. However the spade pins are not sealed in the plugs so you really don't need to get to crazy sealing up IMO. So on the back side were they are soldered, it is covered with a varnish. I used acetone and the end of a small stainless pencil brush to remove before desoldering. Remove and replace. Did not replace varnish. I'll be a Q this year . I got some extra sets available.
Scott
Teenitor Solder Sucker Desoldering Vacuum Pump Solder Removal Tool 3pcs/Pack...

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Re: Aqua hot and Coach heat

Reply #20 – September 27, 2021, 10:41:58 pm

Definitely caps on the verge of failure. Good find and great save!!!

Re: Aqua hot and Coach heat

Reply #21 – September 28, 2021, 09:20:20 am

Not all coach's are the same for sure! We ordered and installed the newest control box for our AH from Rudy. Awesome so far and we need it each night here in Yellowstone!
Our coach has 3 airs on top, not a normal thing for a 40 footer. My zones work this way. Zone 1 is for Air Condition #1, fan and HP. Zone 2 is for 2nd Air C, Fan, HP and Zone 1 on AH for living room. Zone 3 is for 3rd Air C, Fan, HP and Zone 3 Bedroom AH. Bath has the old style switch for bays and bathroom. Took me awhile to figure this out when we first got the coach. So for those of you who have 3 airs, it might work this way. Hope this helps someone!

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