Aqua hot not working on heat strips?

[granvillebarker]

3 hours ago, Ivan K said:

Your exhaust air should stop after 3 minutes or so. It is just to cool the combustion parts down. We don't have the narrow light do I can't comment on its meaning. Watch for the burner starting up again on its own after the coolant temp triggers low temp thermostat at the boiler tank, if it does.

The thin light is the on indicator.  The other light is switch illumination.   Don’t trust the on indicator though If it’s off, my aqua hot electric one and my front genset switch on indicators burned out years ago. 

Edited October 27, 2020 by granvillebarker
Added pics

[Dr4Film]

There is no need to touch those switches once they are on unless you are storing the coach for a period of time.

The 120 VAC Electric Assist will keep the boiler fluid at temp unless there is heavy demand or really cold incoming ground water. Once the demand increases the diesel burner will fire up to keep the boiler fluid at temp.

If the main light goes off on the diesel control switch, that means that your diesel burner has faulted with an error and needs to be serviced or repaired. Turn the switch to OFF and back to ON to see if the light stays on. 

Your wall thermostat(s) for each zone controls the floor heat exchangers and blowers. They determine when they turn on and off NOT the Aqua-Hot switches.

It would also help to know the exact model number of your Aqua-Hot. That can be found on a label inside the Aqua-Hot SS panel housing.

Edited October 27, 2020 by Dr4Film

[Texomaman73]

1 hour ago, Dr4Film said:

There is no need to touch those switches once they are on unless you are storing the coach for a period of time.

The 120 VAC Electric Assist will keep the boiler fluid at temp unless there is heavy demand or really cold incoming ground water. Once the demand increases the diesel burner will fire up to keep the boiler fluid at temp.

If the main light goes off on the diesel control switch, that means that your diesel burner has faulted with an error and needs to be serviced or repaired. Turn the switch to OFF and back to ON to see if the light stays on. 

Your wall thermostat(s) for each zone controls the floor heat exchangers and blowers. They determine when they turn on and off NOT the Aqua-Hot switches.

It would also help to know the exact model number of your Aqua-Hot. That can be found on a label inside the Aqua-Hot SS panel housing.

Here is what I see happening!  It lost temp last night so I shut everything off.  This morning, as Ray suggested I turned on just the electric switch and all three rooms were set to furn and 65 degrees, temp in coach was at 53, I let the electric only run for 2 hours and it didn't heat up the lines at all.  I checked the breaker in the bedroom and it was still on, and the fans never came on. 

I then fired up the diesel and the fans came on immediately and the lines started to heat.  The small indicator on the AH didn't come on at this time but it does come on later after the coach has reached the set point on all zones and the fans have shut off.  

After that nothing changes except that the lines will start cooling down.  I have not ever shut any of the switches off until the temp in the coach is well below where it should have come back on.  The fans will continue to run until I shut off the system but the diesel never fires back up to reheat, with either both switches on or just the diesel switch on (doesn't seem to matter).  

My AH is a 431/12  ser#99831

The fans do shut off when the zone is up to temp, but they come back on later when the room temp drops below set point.  After that they remain on apparently trying to heat the room back up.

[Dr4Film]

My Aqua-Hot model is the same, 431/12 but it seems to be controlled completely different than yours.

I have two control switches, one for the diesel burner and one for the 120 VAC Electric Assist. The photo doesn't show it clearly but the diesel burner blue light is lit up and the 120 VAC Electric Assist is showing RED which means they are both on and active.

I then have three thermostats, one mounted to the wall between the kitchen and bath which controls the three Aqua-Hot heat Exchangers in the kitchen and salon areas. Another thermostat mounted near the bathroom door which controls the single Aqua-Hot Heat Exchanger in the bathroom located under the main vanity. And the third thermostat is mounted on the side of the storage cabinet near the far side of the bed which controls the Aqua-Hot Heat Exchanger for the bedroom which is located under the storage drawers and cabinets where the one side of the pocket door is located. Each thermostat can be adjusted to individual temperatures for each of the three zones. The exchanger fans or heat will not come on until each thermostat is set to ON and the set temperature for that room has not been reached. Once the set temp has been reached the fans and heat will cycle off and on to keep the temperature of that room at the set temp.

You will notice that the 120 VAC Electric Assist is a small 12 VDC switch. That is because the switch is actually wired to a large relay located behind my Intellitec Energy Management System panel that can handle a much larger amp & voltage load.

I would also recommend joining Roger Berke's Aqua-Hot Discussion Forum where you will have access to his expertise and advice.

http://forum.rvhydronicheaterrepair.com/content.php

2002 Windsor Aqua Hot & Block Heater Relay.pdf

Edited October 27, 2020 by Dr4Film
Addition of Aqua-Hot Electric Assist Relay Schematic

[wamcneil]

17 hours ago, Ivan K said:

I am not quite sure if you keep turning the diesel burner OFF or not but if you want to have a warm night, keep both switches ON. Electric alone will likely not do for a chilly night like we have here in N TX today. Not with a single electric element in that era AH.

Yeah, if you need more than just a little bit of heat, you'll need leave both switches on. 

Think of it in terms of heat flow. My AH electric element consumes about 14a@120. That's around 1700 watts or 5700 btu/hr and is equivalent to one little 15a electric space heater.

That 5700 btu/hr of electric heating element in the boiler tank will heat up the antifreeze in the AH tank just like your water heater at home. And when somebody takes a long shower in the house, they're consuming hot water faster than the electric element can replenish it, so if you stay in the shower long enough, you will run out of hot water. And then it takes the water heater a long time to recover and get back up to temp where the thermostat shuts off the element.

Same thing happens with the AH. That 1700w element will heat up the water, but then when you call for the heat (labeled 'furnace' in the thermostat), hot water starts circulating through all the little hydronic radiators and they will pull the heat out of the AH tank a LOT faster than a 5700 btu/hr electric element can replenish it. The electric element will stay on, but the water temperature will continue to drop till the diesel burner fires. 

So unless you only need a LITTLE heat, the electric element will stay on continuously and the diesel will cycle. 

The term "heat strips" was used several times. That's something different. Heat strips could be installed in the AC units to provide resistive electric heat. I don't have heat strips in my heat-pumps and I doubt you have them either. 

The hydronic blowers will definitely run without the diesel or electric being on or hot. The thermostat doesn't know the state of the AH. When the thermostat is set to 'furnace', and it calls for heat, it sends a signal to the AH to start the pump and blowers. The pumps and blowers don't know or care if the boiler water is hot or not. It's like the heater in a car; if you jump in a cold car, your heater will blow cold until the engine warms the coolant. Same in your AH; if you boiler water is cold, the hydronic air will blow cold.

The old AHs are not very smart. There's the electric element that is controlled by a thermostat in the tank, and the diesel burner that is controlled by a separate thermostat in the tank, and that's about it as far as boiler tank temperature regulation. 

Cheers,

Walter

4 hours ago, Texomaman73 said:

... I let the electric only run for 2 hours and it didn't heat up the lines at all.  I checked the breaker in the bedroom and it was still on, and the fans never came on. 

I then fired up the diesel and the fans came on immediately and the lines started to heat.  The small indicator on the AH didn't come on at this time but it does come on later after the coach has reached the set point on all zones and the fans have shut off.  

After that nothing changes except that the lines will start cooling down.  I have not ever shut any of the switches off until the temp in the coach is well below where it should have come back on.  The fans will continue to run until I shut off the system but the diesel never fires back up to reheat, with either both switches on or just the diesel switch on (doesn't seem to matter).  

My AH is a 431/12  ser#99831

The fans do shut off when the zone is up to temp, but they come back on later when the room temp drops below set point.  After that they remain on apparently trying to heat the room back up.

Do you have an ammeter installed to monitor power usage in the motorhome? The electric element should draw about 14a when you turn on the 'water heater'. The current usage should tell you if the electric element is coming on.  Is your thermostat set to 'furnace' all this time, or are you changing the thermostat mode? 

I'm surprised that your hydronic fans come on only when the diesel switch is on. That's not how my 2003 behaves.  

After your diesel burner turns off, does the light on it also go out at some point later? The light on the diesel switch should stay ON. If that light goes out, it indicates the AH is having a fault and has shut down. I had a problem with my diesel ignitor where the ignitor would work when everything was cold, but after the unit heated up, the ignitor would later stop sparking and the unit would shut down. So it would go through at least one cycle and then at some point the burner would try and start back up, not detect flame, the light would go out and then the unit would shut down with a fault.

Cheers,

Walter

 

Edited October 27, 2020 by wamcneil

[96 EVO]

Did you check for hot water after leaving just the electric element on for a while? If you have a 30A shore hookup, you could see on your EMS panel whether the power draw is increasing by about 13A when you turn on the electric element.

I think you have two separate issues. One on the diesel side, which I still think may be a faulty low temp thermostat in the boiler tank.

And the second on the electric side. It's possible the element has burned out. Rare, but possible. Even more possible if a previous owner was using tap water to replenish the overflow tank.

Edited October 27, 2020 by 96 EVO

[David Pratt]

My first question is; do you have the Owners Manual for your coach?

Your Aqua hot system is Model AHE100-01S. To operate the system to heat the coach turn on the Aqua hot diesel burner and set all your thermostats to furnace. The 01S system will not operate properly if all the zones are not set to the same mode. The diesel burner will ignite and heat the boiler and will cycle on and off when the thermostat in the Aqua hot reaches its preset temp of about 120 degF. The heat ex changers(fans) in the coach are controlled by the thermostats and will cycle on and off according to what temperature you have the thermostats set at. You can also turn on the electric side of the system and leave it on, it will not hurt anything.

When the diesel burner shuts itself off the blower will continue to run for 1 to 5 minutes to cool the combustion chamber of the Aqua hot. THIS IS NORMAL.

The Aqua hot does not have heat strips for the electrical portion part of the system. The Aqua hot uses a heating element that is similar to one that would be in you home  water heater. The 01S model does not have the option to switch over to diesel when the temperature gets lower than 45degF and you have the Heat Pumps on. This feature was available on later models introduced around 2004. It takes approximately 2 to 3 hours to heat the water in the Aqua hot and about 20 to 30 minute to heat the water on diesel.

The Aqua hot will consume about .5 gal of diesel per hour of operations.

I have attached the four pages from the owners manual for the operation of the Aqua hot system.

AHE100-01S_Executive - Aqua hot.pdf