Atwood Hydroflame IV problem---SOLVED---

[abaton6]

Hello,

I'm having a little trouble with my Atwood furnace.  Normally you would hear it try to ignite once, then the fan comes on, then in about ten seconds, the flame comes on.  It was working great.  Now, it does this:  You can hear it try to ignite over and over, about twice a second, and with that, the fan tries to start twice per second.  This will continue, and nothing will change.  I checked the flue pipe...clear.  I checked the connections on the board...OK.  Gas pressure is normal.  The L.E.D. on the board will flash at about twice per second also., no pauses.  Any ideas out there in R.V. land?  This is a great forum, nice folks, glad to be here.

Thanx,

Ken Brown
Hartland, Vt.

 

[kbfeip]

I had a similar problem with my Atwood Hydroflame.  The fan would start, it would try to ignite, but no flame.  I had a mobile RV tech come out and diagnose, he claims valve is bad.  Many advise that working on a furnace in excess of 10 years of age is a bad idea.  Additionally, just a few parts alone can add up to near the cost of new.

As a result, I purchased a brand new unit on ebay for about half the cost of new.  I'm due to install it soon.

Good Luck

 

[Gary RV_Wizard]

You said the fan tries to start. If it does not start, ignition will always fail because there is an interlock that prevents it from burning fuel without the fan running. 

Since you hear a click but no action, my first suspicion would be inadequate DC voltage to the furnace. Have you checked that?

 

[abaton6]

Yeah, I'm getting 12.6 V to the furnace.  No luck yet  :'(

 

[kbfeip]

Within the Hydroflame trouble shooting guide I recall a suggestion to check for continuity between the two separate coils.

 

[abaton6]

kbfeip,

What coils are you speaking of?  ???

KGBrown

 

[kbfeip]

Ahhh.....

Sorry if I wasn't very clear.

There are two encapsulated electrical coils near the burner exhaust.  They are black, about 1" diameter, and 2" long, each with a red and yellow control wire attached.  Depending on the model, they can be mounted either vertical or horizontal.

Check for continuity between the two coils to insure that neither have any shorts.

I'm no expert...I only recall what I read from the trouble shooting guide in my old furnace manual.  You might find more information at: http://www.atwoodmobile.com/Service/Trouble/dsi.cfm

Kurt

 

[Gary RV_Wizard]

Can you get at the fan itself and apply 12V to see if it runs? As I said, if the fan doesn't run the fan sail switch interlock will prevent ignition (the gas valve won't open).

 

[Karl]

I believe the coils he's talking about are the electrically-operated gas valves. There are two of them, and both must operate for gas to flow. But as Gary pointed out, unless the fan is running and putting out sufficient air, the 'sail switch' will not make contact and the valves won't even try to open. Check all electrical connectors for the furnace (outside and inside) for looseness or corrosion, make sure all ground wires are tightly screwed down, etc., then wait outside while someone else turns the furnace on. If you don't hear the fan running steadily, that's probably your problem.

 

[abaton6]

Problem solved, 

It was my power supply.  Yes, I had 12.6 volts when not in use, but when the furnace tried to run, the voltage varied wildly.  I switched to battery and BOOM!  It ran like a charm.  Thank you all for your input.  I'll keep this fix in the back of my mind for future reference.

KGBrown

 

[Gary RV_Wizard]

Glad to hear it has been resolved. Also happy to hear that our suspicion of a 12 VDC power problem was right on the money. Makes us gurus look good!

 

[rclark]

Gary you should write a book!!  ;D ;D

I've gotten more quality info from your posts than I have in Bob Livington's whole book!!!!!!!!

Thanks to you and all the rest of the forum members that help us newts out all the time!!!!!

Randy

 

[Gary RV_Wizard]

I'm embarrassed, especially since I think Livingston's book is pretty good and I carry one in the motorhome. But thanks for the kind words.

We see and hear of a lot of problems here, so some times we can pass on the accumulated wisdom of the entire group to those who need it.

 

[Tom]

Gary,

You're being extremely modest.