Strange Atwood Heater Symptoms

[CharlesinGA]

Ohms test will just tell you the coil is OK. The valve could be sticking and not opening fully even with full power to a good coil. I would just look at replacing it properly.

Charles

 

[Old_Crow]

I found a bad gas valve by sitting next to the heater while my wife turned up the t/stat. When it started trying to open the gas valve(heard the click)I tapped the valve with a screwdriver handle and the heater fired and ran. Replaced the valve and all was well.

 

[CncDean]

So one problem solved but another is still there.
I removed the orifice from the gas valve and discovered it packed with small pieces of something. I suspect that it’s pipe putty from the old regulator. There was quite a lot on the thread.

 

[CncDean]

The other problem is that there is 13v or so going into the board at the blue wire but once the furnace starts up it drops to 11.4v at both the blue wire coming in and the red blower wire coming out.

How would the main blue wire coming in drop 2v just from the blower starting?

Is this a thermostat thing? Although the standard style therm is brand new and from dometic.

 

[CncDean]

Update:
So I guess this is my mistake.
When it wouldn’t stay lit before I knew that the gas valve was clogged, I ordered a new igniter/flame sensor. I just put it in when I cleaned the orifice.
It looked like it was a 1/4” from the burner so I didn’t Bend it closer.
What I realized is that it was staying lit for the same amount of time as the Igniter was clicking. 7 seconds.
So I pulled it out and bent the igniter closer to the burner and it started working properly.

I’m still unsure why there’s a voltage drop at the board.

 

[CharlesinGA]

Update:
So I guess this is my mistake.
When it wouldn’t stay lit before I knew that the gas valve was clogged, I ordered a new igniter/flame sensor. I just put it in when I cleaned the orifice.
It looked like it was a 1/4” from the burner so I didn’t Bend it closer.
What I realized is that it was staying lit for the same amount of time as the Igniter was clicking. 7 seconds.
So I pulled it out and bent the igniter closer to the burner and it started working properly.

I’m still unsure why there’s a voltage drop at the board.

The motor draws a lot of amperage. Probably a 14 gauge wire, so I would expect a heavy voltage drop thru a long run of wire.

When its running, measure the voltage at the fuse, measure it at other terminals for stuff that is not in use.

Not too out of the ordinary I'll bet.

Charles

 

[CharlesinGA]

I filled a propane tank this morning at a propane supplier - ya know, big tanks a delivery tank trucks.
While in the office paying, I noticed a large number of regulators and switch over valves on shelves. They had everything.

Could be RV dealers are short because they didn’t stock much and after using up the few they had, are now waiting for resupply.

I notice the the Camping Worlds seem to be out of everything but other sources seem have availability. For example, I need a replacement Furion thing. None of the rv places have em but I can get one through Amazon in 4 days.

If you look at Amazon, they are all unavailable now. One of the RV companies said they had requests in to four different manufacturers for regulators. Its going to be months before this settles out. Companies buy the cheap China made stuff and this is what happens. Fairview makes them in Mexico (though I would not want one, they are failure prone) and Marshall Excelsior makes them in the US, and Cavagna makes them in Italy, yet they buy from China.

Edit: looking at Cavagna website, their HQ is in Italy but the manufacturing is in China, Thailand, India, Chile, France and Russia, so take your pick.......From reading descriptions of what each facility does, its either the facility in China or the one in Portugal.

Charles

 

[JayArr]

I’m still unsure why there’s a voltage drop at the board.

Start tracing backward, a voltage drop under load could be a bad connection somewhere. Open all the connections and look for corrosion or oxidation. Replace any Marrettes that aren't shiny and restrip wires so you get nice new copper to copper connections. Sometimes you can even find it with your hand, grab a wired connection while power is running through it, if it gets warm it's bad, warm connections are dropping voltage.