2016 Dynamax DX3 - Aqua-Hot Feedback

YouTheMann · 12-12-2015, 07:21 AM

As I understand, the Aqua-Hot system was first implemented on the 2016 Dynamax DX3 line.

I live in Colorado, keep my rig in an un-heated barn and in the process of winterizing. I have decided to blow out the water lines with compressed air versus running rv antifreeze through the fresh water lines.

Question #1
As I understand, the Aquahot system utilizes a heat exchanger system to heat the coach hot water on demand versus a tank based system. I have thoroughly read the manual but can't determine if it is safe to run the aquahot system should I decided to heat the coach to do some work inside without water in fresh water lines.

Question #2
On our trip from from Florida back to Colorado in late Nov, overnighted in Amarillo Texas. That night had sub freezing temperature i.e mid 20's. Had the coach temperature set to 69 on the both thermostats, enable furnace mode with both the gas and electric in operation on the aquahot system. Notice that the coach had very uneven temperature distribution. While the hallway and bathroom felt toasty warm, the front of the coach i.e. sofa areas and the bedroom (door closed) were chilly. The system could not get the temperature on either thermostat above 61. Hot air was blowing out of both zones and all vents I could find. Anybody else with similar experience.

Question #3
On another stop on our trip back to Colorado, was using the heatpumps versus the Aquahot for heating the coach when I got up in the morning notice that the coach had switch over to the Aquahot system and disable the heatpumps. Is this normal operation and if so any idea at what temperature does this switchover occur at.

Question #4
Although unrelated to the Aquahot system, does anybody know if the floor in the coach is insulated. Noticed on the chillier nights i.e 30's/40's that the tile floor was really cold.

Regards,

**bclemens** · 12-14-2015, 09:16 AM

1. Page 13 of the owners manual on the 400LP reads as follows "NOTE: The Aqua-Hot can continue to be used for interior zone heating once the domestic water heating system has been drained and winterized"

2. That front area is the hardest to heat due to the cab heat loss. I assume slides were out...in some cases the slides being in can block the thermostats. If you continue to see this issue we may want to look at adding an exchanger to the front zone.

3. Normally the heat pumps will cut off below 42 degrees. That's about when they stop functioning. I'll have to look a little further into this as I'm not 100% what triggers the change over. I'm not sure if it is actual temps...or if the heat pumps just cut off due to being inoperable.

4. Yes. It is a vacuum bonded floor with block foam insulation. I wonder if it is residual cooling. The floor is actually "snap stone" so not only is the floor insulated, but it actually floats on a plastic track, so its not directly on the sub-floor. That should help even further. Unless that cold air trapped between keeps things cooler. Once the coach gets up to temperature the tile should warm up though.

**bclemens** · 12-14-2015, 09:24 AM

I posed your question #1 to Aqua Hot directly and this was their official response.

"You cannot winterize an Aqua Hot by blowing it out with air. You will need to make sure your customer uses winterization antifreeze, and he has to get the antifreeze out of at least one hot water faucet. If he does not use antifreeze he will not get all the water out and the unit will probably still freeze and need to be replaced.
As far as using the coach when winterized, He will have to have some kind of liquid in the water lines, whether it is water or antifreeze because the 400 is a hot water priority system, and has a Low Temp Cutoff thermostat that shuts the heat off when you run hot water. Because of this thermostat if there is only air in the cold water inlet line, the thermostat may not register properly and the heat may not work. He can run both the burner and the electric element even if the water line is winterized."

YouTheMann · 12-14-2015, 10:06 AM

Bclemens,

Thank you for response.

Followup to your post.

- Since the recommendation is winterize the potable water system with RV antifreeze, do you happen to know where the pump is on a 37 TS model. I have done a cursory look for it but have not been able to locate it. I believe that the water tank is located underneath the cabinet where the closet/drawers are for the bedroom based on where I see the water fill and the drain for the tank. Do you know if there is a winterizing pickup hose on the suction side of the pump, or am I going to have to add the RV Antifreeze through the water fill. FYI, my dealer indicated that air blowout was sufficient for winterization, having said that he is located in southeast texas so this method may be suitable for that area of the country.

- I agree with you that there probably needs to be a heat exhanger near the front of the coach, the aquahot installation manual does show a heat exchanger at the front of a coach on a typical installation. I really don't see a suitable location, but is this something that the factory could upgrade or would I have to go to a third party for this upgrade.

- Another note on the auto cutoff of the heatpump and switch to aquahot in colder weather, I notice that the furnace light on the thermostat is not lite and the aquahot system is running when this happens.

Regards,

**bclemens** · 12-15-2015, 10:31 AM

Pump is in the closet/washer dryer area. Should be an access panel. We do not have a take up tube, but I've talked to engineering about adding one for future models. its a simple 3 way valve and length of hose.

I know a lot of guys that blow the lines out. Aqua Hot may just be doing a CYA, but the temp sensor does make some sense. I'd test it and see where it comes in at if it was mine.

Heat Exchanger - we can take a look at it. Sometimes just adding another "cozy" dumps the heat in there quicker. When you get a chance you can set something up with a dealer and we can see what needs to be done. Shoot me your VIN and contact info and I'll have warranty look into it. See how many exchangers you have now and see if we need to add one or look into T-stat location.

You may also like: