8525 III DLCP turns on. then off, then on, then off, then on

[marknoo]

So I just replaced the circuit board in my heater, I also replaced the fan. It does have a loose connection to the circuit board but it always did.

When I first replaced everything it would come on, go off, then come on and work like it should.
Today it seems to want to come on, go off, come on, go off, come on, go off and then do its job.

I went out and wiggled the connection but I need a more reliable fix than that.

Can anyone tell me what they think might be trouble and how to fix it?

Thank you.

I also got a new thermostat.

could that be the problem, because the old thermostat never did this stuff.

 

[Henry J Fate]

The loose connection is something you should resolve first. If you replaced the board that the loose connector connects to, look closely at the connector making sure it is clean and all the pins look good. Loose connections will worsen over time and will react to thermal and moisture changes. All the pins in the connector should be firmly connected to the board.

If you still have the old thermostat, you could reinstall it to see if that changes anything but I do not expect it will.

There are other possibilities beyond the loose connection but I would not suspect any of them until that connection to the board is solid and make sure any other connections are not being compromised.

Also.... When you mentioned the heater turns on then off multiple times before working properly, is there heat coming from it when it turns on and off or is it just the fan running without any heat?

 

[marknoo]

First off, I apologize for not getting back to you sooner.
Second, thank you very much for answering. OR maybe thanks should be first. Anyway, thank you.

When the heater is doing its start/stop thing the fan runs but there is no heat.

Also, it doesn't stop "nicely". It stops very abruptly, it doesn't gently power down, it just cuts out and stops, then a few seconds later it kicks on.

About the connector, can I just take a picture of it and take it to the RV store and then cut and re attach the wires. Should I look and see if I can use a set of pliers and maybe tighten the slide on connection up. It is quite loose, how do I deal with it?

 

[Henry J Fate]

With some effort you should be able to clean and tighten the connector to the board. Use a good magnifier, light and a pick. (I use a fine wire pick that a dentist uses) If the pins inside the connector are still in good condition, it is usually possible to ever so slightly bend them to create more pressure on the control board pads thus being tighter. You may need to clean the pins also if they look bad. Clean the control board pads too. A q-tip touched in a little Alcohol should clean the board pads up. The pins in the connector may need some scraping with the pick and then swabbed clean with a q-tip and alcohol.

When re-adjusting the connector pins, lots of light, good magnification and small adjustments.

If the connector must be replaced, you will need to match it up. I believe it will be searchable by using the model number of the furnace. If that fails then you could cut the wires and bring it to a dealer to match or possibly just disconnect the board and bring that.

You may need to by the complete wiring harness. The connector by itself requires special tools and expertise to replace. With a new harness you could cut the wires to the old connector and the new connector and then splice the new connector to the old harness. Soldering with shrink tubing is best but properly fastened crimp connectors will work.

The other option is to replace the entire harness if it is easy enough.

 

[marknoo]

My buddy is an IBEW electrician. So I asked him to look. The connector is OK he says. Then he had me show him the whole cycle. But this time I listened from outside the trailer, right next to the hatch that opens up to reveal the heater.

The unit turns on, then you smell gas, next you hear a clicking, and it does not ignite. So the machine tries it again. It does not ignite.  So it seems to be trying 3 times and then it shuts off completely, than in a couple of seconds it starts another cycle and on the second cycle it starts. So the fan comes on, gas comes out, and this time it ignites and then it does it job normally.

So it sounds like it may be a problem with ignition.

I'm still going to tighten up that connection but does anyone know how hard it is to fix an ingition problem.

This heater so far has a new blower motor and a new circuit board I put in over the summer (rather my buddy the electrician did)

 

[Henry J Fate]

Good you are making progress.

The ignition sequence is just as you describe. Probably need to adjust the gap of the ignitor/sensor, clean it and realign it. The manual is very clear on that task.

If you have not replaced the ignitor/sensor, consider replacing it with a new one.

The other variable is the nozzled gas flow into the chamber. Be sure the nozzle is clean, free of dirt and in good health.

 

[marknoo]

So a new motor, a new circuit board, a new burner did not fix the problem. I just took my board into the RV place and they tested it and it is fine.

They told me to check my igniter switch in the combustion chamber. They said if it is bad the motor will just keep running. which mine does, it just keeps going and going but no heat.
The other thing they said was it could be the sail switch but it was unlikely because the fan stays on.

How big of a pain is this igniter switch going to be. I am not a mechanic, so if I hire someone how long would it likely take and does that sound like the right fix.

It needs to be fixed but I am really racking up some repair bills here, new blower, new circuit board, new burner. I would just like to get it fixed.

 

[alan6051964]

So a new motor, a new circuit board, a new burner did not fix the problem. I just took my board into the RV place and they tested it and it is fine.

They told me to check my igniter switch in the combustion chamber. They said if it is bad the motor will just keep running. which mine does, it just keeps going and going but no heat.
The other thing they said was it could be the sail switch but it was unlikely because the fan stays on.

How big of a pain is this igniter switch going to be. I am not a mechanic, so if I hire someone how long would it likely take and does that sound like the right fix.

It needs to be fixed but I am really racking up some repair bills here, new blower, new circuit board, new burner. I would just like to get it fixed.

you don't need to be a mechanic to work on these, they are simple. first turn your propane off at the bottles, outside the rv access door to furnace, remove any protective parts that cover the propane line, disconnect the propane line from the gas valve, take a few pics of how the wires are connected to the solenoids , remove any screws that hold the assembly in the furnace, carefully pull the assembly out of the furnace , everything should all come out as one piece. now you will see your igniter, burner parts , from here, its just a matter of removing and replacing with new parts, as most are just screwed into the metal box/frame right there.

 

[marknoo]

so I tried to find the igniter swtich but could not find it, OH, not by looking inside the furnace but on this diagram. I don't know what the combustion chamber is so I need to find it and then find that sensor.

Does anyone see it on here:
https://pdxrvwholesale.com/products/atwood-hydroflame-furnace-model-8525-iv-tune-up-kit

that is kind of the list I have been using to sort of figure out what parts I need.

What does this think look like so I will know what to go after.

 

[Henry J Fate]

If the fan is running, this does NOT confirm a good sail switch.

The control board is the switch for the electrode/ignitor.

I would replace the electrode and verify that the sail switch is working properly.

 

[Gary RV_Wizard]

There is no such thing as an igniter switch. The igniter is an electrode that creates a spark as it shorts to ground when the circuit board sends a high voltage pulse through it.  The only thing you can adjust is the distance from the sparking electrode tip to the adjacent ground electrode, which should be 1/8th inch.  The circuit board opens the gas valve and sends the ignition pulse several seconds after the sail switch closes.  The several second delay is for the fan to purge any previous gas or exhaust fumes from the burner chamber.

This is covered in the Atwood Furnace Service Manual. Get a free copy at http://bryantrv.com/docs2/docs/hflamefurn04.pdf