I need operating education on Aqua-Hot

[JohnParker]

I acquired an '07 DSDP in August and have really enjoyed it so far. But, there are some things that are still a mystery to me and I hope some of you Newmar owners can give me some guidance.

I live in the Houston area and have taken a few trips since I got the DSDP. But, the trips have all been in the south and southeast. Nothing into the mountains or north of Arkansas yet. And, as I am sure all are aware, the weather has been on the warm side. So, no opportunity to really check out the operation of the heating systems until now.

This DSDP has roof air conditioning with heat pumps. It also has a Hydro-Hot (Now called Aqua-Hot?) heating system for hot water/engine block heat/interior heat. I have read the manuals and looked all over for controls. I am obviously missing something.

This morning I set the thermostat at 50 degrees in 'warm' mode, turned on the Hydro-Hot diesel and electric switches, and waited to see what would happen. The HH pump came on to the circulate the heat exchange fluid. The diesel burner came on and ran for about fifteen minutes to heat the circulating exchange fluid. The roof air units came on but shut down because the generator was not running. The diesel burner shut down but the circulating pump continued to run. I started the generator and after the normal two minute delay, the roof units came on blowing hot air out of the ceiling ducts as expected. But, nothing from the HH, and nothing from the floor vents.

My understanding is that I should be able to operate the HH from shore power or from the inverter to get heat in the winter without operating the generator or roof units. Is there a separate thermostat? If so, where is it? If the HH operates from the central thermostat that also controls the roof units, how do I keep the roof units from starting or running while the HH is on? I'm sure that sometimes in severe weather I might want both roof units and HH to run for heating. But that will require the generator to run and I would rather not do that more than needed.

[harleyman134]

HH operates the heat via the thermotsat. Set the thermo to furnace, you will get heat out of the floor/wall vents, the overhead units will not come on when using HH for heating.

[JohnParker]

HarleyMan;

Thanks. I must be missing something. When I cycle the thermostat mode button it goes from 'cool' to 'heat' to 'off' and back to 'cool', etc. Is there a 'furnance' button that these old eyes can't see?

[Ronnie Bledsoe 2006 Dutchstar 43']

John, have you turned the rocker switches on? They are located in the cabinet over the dash where you check the fill levels of fresh water, grey, black etc. Should be 2 switches, 1 for electric and 1 for diesel. Temp control for heat is the thermostat. I've found that for heat in cold weather and hot water for showers the diesel is best. You can operate both switches at the same time.

[harleyman134]

Dang, my thermo will cycle between off, heat, cool, furnace and fan when I cycle the mode button on my Dometic five button thermo. I only have two zones, try cycling the mode button on a different zone. Looks like I might not be able to help you, sorry about that

[JohnParker]

Ronnie;

When I did the test this morning I had both the 'diesel' and 'electric' switches in the 'on' position and both of the lights were on 'green'. I had used the system for hot water in the 'electric' mode previously and found that sufficient for sinks and short showers. Of, course ambient at the time was 100+. I expect to use the diesel in the winter. I think the real problem is my failure to properly operate the thermostat.

Harley;

I did try cycling the modes but only for one zone. I will try the other zone to see if I can find a 'furnace' setting.

[Ronnie Bledsoe 2006 Dutchstar 43']

If I remember correctly the Furnace mode is right after the heat pump mode on your thermostat. I think it is normal for the circulating pumps to run after burner shutsdown. If you go to the website for aqua hot they have a complete manual about 75 pages that goes into detail on the unit. I printed it out and have it in the M/H. Also their tech support staff has been great in assisting me.

[ottffss]

1) All Tstats must be in the "furnace" mode - you can't run heat pump and AH simultaneously. The Tstats control the circulating pumps/register fans. The burner and elec heat element are controlled only by the temp of the coolant in the system. Sounds like you have normal burner operation.
2) Domestic hot water use OVERRIDES heat and the heat will shut down while domestic hot water is used. A "stir pump" is active during this time. The thermistor (a.k.a. gizmo thingey) that controls this switchover is a common failure point and you can simply jumper it out of the circuit right on the control board if it is failed.
3) AH/HH is all 12v DC. Only the 1,200 watt elec element is 120v. As you found out, at only 1,200 watts (a hair dryer) the elec only provides a some hot water and limited heat. On diesel mode only 12vDC is needed. Perfect for boon docking.
4) The AH (HH is the old company name) will keep you toasty to -30F (yes negative), no problem.
5) www.rvhydronicheaterrepair.com is your best info AND service source.
6) Do read through the manuals on the AH web site, it can be a little tricky to figure out what is going on when. Aqua-Hot Heating Systems Inc.

[JohnParker]

OK Guys; here's a puzzle.

I thought I was missing something because I can't believe that the previous owner didn't have this issue or address it if he did. But, apparently, all is not as it should be.

I went back to the MH this AM just to look agaiin and to follow up on the suggestions you guys have made.

It makes sense that the thermostat would have a 'furnace' setting and that both zones would have the setting otherwise the AC would be trying to fight the furnace.

However, the thermostat in this MH seems to be missing a critical option.

The thermostat is a Duo-therm Comfort Control with 5 buttons and 2 zones. In either zone setting when cycling the 'mode' button the little screen says... Off, Fan Only, Cool, Heat Pump, Off, Fan Only, Cool, Heat Pump, Off, etc.

I suppose the next step is to take the thermostat off the wall to see if there are loose, unconnected wires. But, I would think, if the thermostat had a 'furnace' option it would say so on the little screen even if no wires were connected.

I am really surprised at this situation. I have to wonder how the previous owner stayed warm in the winter.

Any suggestions?

[Doc Mark]

My suggestion is to call Newmar and have a tech troubleshoot with you. (866) 463-9627

Mark

[soricobob]

My first question is: 1. How many zones do you have? Probably one of those zones does not have a furnace option. 2. When you put the HH on do you put on the fan? The fan settings (on the overhead panel) must be on to have the HH operate. 3. At what outside temp are you testing it? HH won't work when you force it.

[harleyman134]

there are some "dip" switches on the control board of the a/c unit itself that might need to be changed to recognize the furnace, I don't think the problem is with the thermostat itself. I do agree this needs to be resolved, you can use "furnace" mode while driving for "free" heat. I tend to agree with the suggestion to call Newmar for help with troubleshooting this problem. Good luck and keep us updated.

Sonny

[Ronnie Bledsoe 2006 Dutchstar 43']

I went to the Duo Therm web site and if I understand properly the unit reads only what is wired to the thermostat. If you google Duo therm comfort control you can find op instructions and install info. for 5 button controller.

[bucks2]

Quote:

Originally Posted by ottffss 1) All Tstats must be in the "furnace" mode - you can't run heat pump and AH simultaneously. The Tstats control the circulating pumps/register fans. The burner and elec heat element are controlled only by the temp of the coolant in the system. Sounds like you have normal burner operation.

I run my AH and heat pump simultaneously all the time. AH provides hot water for domestic use regardless of how you're heating your coach. My Thermostat can be in heat pump or cool mode and the AH continues to provide hot water with either electric only, diesel only or electric/diesel switched on.

I can also preheat the engine using circulating pumps with the coach thermostat turned off, so the thermostat doesn't control circulating pumps exclusively.

To make your statement correct you must state that you can't use the AH FOR COACH HEAT at the same time as the heat pump.

Ken