Hydroflame FA 7615 circuit board and ignitor

[Mr_Mark]

My furnace sometimes will not ignite and thus blows cold air until I shut it off. Not often, but often enough that I usually wake up in the morning with it running and blowing cold air.



I ordered a new circuit board and ignitor as the old ones are original and thought it wouldn't hurt to replace both at this point. The only troubleshooting I have done is to test for leaks and there is none. I have also replaced the blower motor.



Some issues became apparent when the parts arrived. The new circuit board is much smaller and the ignitor lead is in a slightly different location so the plastic housing will require modification. All the new connections are spade terminals as opposed to the old push on connections, which isn't a big issue for me to change as the ignitor came with spade adapters. However the original high tension lead is too short due to the changes and will require a new (longer) wire. This did not come with the kit, so I am wondering where to get a wire like this or if a regular wire will do. I'm guessing a regular wire will not do as there is writing on the original which says 250 degrees celsius.

[Mr_Mark]

Yes it is an older unit, from an '85 Nissan micro motorhome.

If it does it and I catch it in time I will turn the thermostat down for about 5 seconds than turn it up enough so that it sparks again and it has worked every time. All with the blower still running.


I have ruled out leaks and issues with propane - I do know the ignitor is routinely carboned up and I used to take a wire brush to it but now I cant be bothered. I was wondering about why it wouldn't detect the flame not lit and keep running but it seems to reason it is just older.


It is a fantastic way to drain the battery if I am not around.

Anyhow, going to try a furnace store tomorrow and see if they have something.


Thanks.

[dougrainer]

drsteve wrote:
If the furnace doesn't light, the blower fan should not continue to run.

They do when they are OLDER furnace boards. Older Furnace's did not have the Fan relay ON the control board to shut the blower OFF when the furnace failed to light. Doug

[BFL13]

drsteve wrote:
If the furnace doesn't light, the blower fan should not continue to run.

It did with my 8531-II. Only way to fix that was to turn off the furnace at the thermostat and restart.

I replaced the board with one from an 8531-III, That board is smaller and has no plastic cover, but the connections fit ok. So the II now works right and the board has no cover like before. It is covered by the door's "inner door" though.

IMO just add on some more wire of the right gauge, but one of the real furnace techs on here might have other thoughts.

EDIT- here is something on the 7600--(also 7200 and 7700) scroll down to page 10 of 21 for other steps besides changing boards.

http://bryantrv.com/docs2/docs/FA7200.pdf

[drsteve]

If the furnace doesn't light, the blower fan should not continue to run.