Community Forums

Steve 9501 · 09-24-2019, 08:53 PM

Hi everyone! Obviously I am new here. I am working on a camper for a friend and in my search for information found this site.
His furnace is not working. It will run the purge cycle then fail to ignite and will shut down.
The code I am getting from the blinking light is 5 flashes, which the book says indicates a module fault.
I have been searching the internet for days and can only find problems with 1 through 3 on the trouble codes.
My question is what is the module and how bad of a job is it to change?
I am sorry but I don't have a year on the unit but it is an Atwood Hydro Flame 8500 IV.

Also on a side note the water heater also quit working. The water in the tank is scalding hot but the water from any of the taps is cold to slightly warm ish. I ordered a new mixing valve. Are these easy to swap out? I am concerned with pulling the old one out without damaging the water heater tank.
Thanks for any assistance!

Old-Biscuit · 09-24-2019, 10:12 PM

Module........circuit board

Water Heater Mixing Valve
Screws into WH Tank HOT Outlet
Cold water line connects to mixing valve
Hot water to RV connects to mixing valve

They are a problem....they clog on hot side due to scale/calcium

Normal t-stat controls heating to 155*F
Mixing valve controls hot out to RV at 130*F

Steve 9501 · 09-24-2019, 10:22 PM

Thank you for the information. I thought it looked like the mix valve just screwed into the water heater but I wanted to ask someone that knew to make sure. It is in the storage and hard to get to. I can get in to work on it, but don't want to get in and out of there any more than I have to. I also didn't want to put a pipe wrench on it and break something.
So, opinions, where is the best place to have her go to get a circuit board? And is that something that just plugs in or is it soldered in somewhere? The diagram in the book looks fairly straight forward, but again I don't want to come across any surprises and make the problem worse!

Old-Biscuit · 09-24-2019, 11:07 PM

The Mixing Valve can be a bugger depending on amount of scale/calcium build up ----most times access complicates removal.

Circuit Board
Unplug wire connector.....remove 2 screws......slide board outNew one in...plug connector onto board

Atwood 31501 (OEM...replaces old part numbers)

Dinosaur Electonics UIB-S (aftermarket ---better quality)

Steve 9501 · 09-25-2019, 03:04 PM

Thank you again for taking your time and giving your knowledge.
It sounds like the mixing valve is just like any plumbing around here, just have to watch the hard water buildup and take my time breaking it loose.
I told the owner to order the circuit board so when it comes in we will see how it goes.
Thanks again!

**hamm2018** · 09-25-2019, 07:31 PM

Sometimes if the outside shower is left on or open it will mix the hot/cold water and give the symptoms you describe. I would check it first. Just a thought