Suburban Furnace Issues

[cedarwings]

I am beyond frustrated with this furnace. I started having issues in December and my tech replaced the control board which worked for about a week. The furnace died again, so he took it out and bench tested it for several days and couldn’t get it to fail. He reinstalled and it worked again for another couple of weeks. Yesterday this happened. It is still throwing heat but struggling so I finally turned it off. I have checked for rodents inside but nothing showing. Please check out both videos, first is from inside the RV and second is from outside in front of the furnace panel. Any thoughts????
2022 Reflection 367BHS purchased new.

 

[old RV guy]

1. A new control board can fail 5 minutes after it's installed. 2. DIY furnace repair is largely a a matter of replacing parts until the culprit is eliminated.
It's advisable to carry a spare control board so first thing I'd do is replace the existing board. If that's not the problem the board you replaced can be the spare.
Meantime, an intermittently opening and closing sail sw, limit switch, bad igniter/ flame sensor, weak fuse in the thermostat, are possibilties.

 

[TonyL]

At what elevation are you, a lot of furnaces don't like working at 5000ft or over

 

[cedarwings]

At what elevation are you, a lot of furnaces don't like working at 5000ft or over

I'm in a valley - 300 ft elevation.

 

[TonyL]

That rules that issue out then!

 

[TonyL]

Just listened to the videos, assuming the furnace is getting a good voltage, then the blower is either failing, bearings seizing, or is twisted when installed but is free when tested on the bench.

 

[Kirk]

Any thoughts????

Replacing a circuit board to resolve a noise makes no sense at all. I have worked on dozens of RV furnaces and there are several things that can cause noises. The most likely is for something to be getting into contact with the rotating blower. It is very difficult to pin down the noise without being there but I sure wouldn't go back to an RV tech who changed a circuit board to stop a noise. I wonder if he really did change it? Did he leave the one he removed with you?

DIY furnace repair is largely a a matter of replacing parts until the culprit is eliminated.

That may be true for you, but it isn't the case for those with technical knowledge and experience. The first thing is to get a copy of a service manual. They are readily available online.

 

[John From Detroit]

Sounds like something is hitting the blades on one of the blowers.. This results in lower blower speed and may keep the sail switch from sailing. But I'm guessing blower hitting something problem

 

[old RV guy]

Sounds like something is hitting the blades on one of the blowers.. This results in lower blower speed and may keep the sail switch from sailing. But I'm guessing blower hitting something problem

If the sail switch isn't closing the furnace will light but only for a few seconds. After several attempts it will need to be reset. I'm not a trained technical furnace expert like the gatekeeper clique, but there's nothing that could be interfering with the rotation of the blower that wouldn't have shown up during a bench test. Nor is there anything in a readily available online service manual that's going to address that issue or bad mouthing the service tech who did the work going to accomplish. He was there.

 

[RayIN]

To me both videos are pointing to the blower motor as probable cause.
As to why, there is a minimum of heated air volume (after the blower fan) for each furnace. Then excessive back-pressure affects air flow speed and the over-temperature switch.
This translates to not enough warm air ducts for that specific model furnace.
You cannot solve your LP furnace problem without downloading a copy of your models service manual and following the trouble-shooting guide.

 

[Kirk]

Last seen Friday at 11:02 AM

I wonder if Karen is coming back? Did she get it resolved?

 

[Gary RV_Wizard]

If the sail switch isn't closing the furnace will light but only for a few seconds.

No it won't. Until the sail switch closes, the controller board won't even attempt to ignite the burner. No gas will flow and no ignition spark will be generated.

You may be thinking of the flame sensor. Once the ignition is attempted, the controller waits for the flame sensor to report successful ignition. If the success signal is not received within several seconds, the controller shuts off the gas flow to the burner.

 

[cedarwings]

Last seen Friday at 11:02 AM

I wonder if Karen is coming back? Did she get it resolved?

Hi Kirk - thanks for the reminder to post the resolution. My apologies for not doing this sooner. I had a "two-fer" with this furnace... First the board failed and then the motor failed 2 weeks later. My RV tech is red seal certified and I have complete faith in his integrity and work ethic. The furnace is now working beautifully but I had to endure a month of no propane furnace during our cold snap (-10 c). I did contact Suburban to express my dissatisfaction with their product components and asked that they convey my concerns to their procurement department. They responded Thank you for the help everyone!