HydroHot Failing

[JavaJelly]

In February I had Newmar do annual maintenance on my HH. It has always worked great. Ever since this maintenance it can't keep up with hot water in the shower.

I checked coolant level and turned off furnace. Water starts out hot but, slowly goes to luke warm after a minute or so. Turn water off, HH "chatches up" then water cools down.

Wondering if there was something simple to check before I have to take it in for repairs.

As always thank you.

[JavaJelly]

In February I had Newmar do annual maintenance on my HH. It has always worked great. Ever since this maintenance it can't keep up with hot water in the shower.

I checked coolant level and turned off furnace. Water starts out hot but, slowly goes to luke warm after a minute or so. Turn water off, HH "chatches up" then water cools down.

Wondering if there was something simple to check before I have to take it in for repairs.

As always thank you.

[Rick Long]

Go to your outside shower and check that it's turned off at the valves and not just at the sprayer.
What happens is... the cold water mixes with the hot and goes through the system. There realy should have been a check valve on the hot side to prevent this, but it's the same for most brands of RV.

[Lug_Nut]

Scott, Are you sure the diesel burner is running full cycle? If you listen to it when it starts it should kick in within 30 seconds of start and run continually for a good period of time. Additionally, make sure the switch controlling the burner has a solid, no flashing, pilot light. If it is flashing it is displaying a fault which can be identified by the sequence within the manual.

Peter

[JavaJelly]

Rick & Peter,

Thanks for the tips. Neither suggestion seems to be the answer.

Rick - Had the outside shower closed but, retried it.

Peter - No errors anywhere.

Last time this happened was when I went too long w/o maintaining the HH. The burner was burning but, it couldn't keep up.

However, I just had it maintained in Feb. at Newmar and it has few hours on it since.

I know it is getting to temperature because at first the water is scalding hot, then quickly goes to warm until it becomes barely luke warm.

It seems to heat the coach just fine at night.

[petefl]

Scott:
Could it be a faulty thermostat. Causing the HH to cut off too early?

[RVDude]

I am assuming the burner is functioning correctly. Blower on for about 30 sec, flame ingites and stays on for several mins, flame out and blower on for 2 mins. Full off.

I'd also try using just 120v elec alone and see if the same hot to cool water temp happens. This will rule out the burner.

Do the heater ducts alone stay hot? This will tell you it's in the coolant circulation system.

My bet is - At this point it could be the internal mixing pump not circulating the coolant to heat the domestic water. You should hear it run (a quiet hum) in the AquaHot unit while running hot water. Run on 120v only, open a hot faucet for a couple mins, if you hear nothing inside the AH unit it's this pump. Might have gotten unplugged at Newmar accidentally. The pump(s) is right inside the cover the round things about the size of a hockey puck. Make sure they are all plugged in.

It could also be the mixing valve in the back which is getting jammed up. Fine at first and then closing down. But this is really unlikely.