furnace

[joe0508]

I have an odd situation with my furnace.I am sorry to begin with that i dont have much info on make and model but maybe i can get some more possibilities from the info i provide.The thermostat is a atwood hydro flame furnace thermostat 38452.Look it up on ebay you will see a picture of it.Anyway when i set it to a certain temp on the opposite side of the rv behind the wall i can hear a buzzing sound and the when this happens it seems to effects the cycling as well.Any ideas what the buzzing sound is?It all most sounds machanical mixed with something shortening out.Im pretty sure its related to the thermostat but i dont know if it is something that is gonna burn my wheels down or not?Thanks and i appriciate any ideas y all have.

[joe0508]

I think i will retire the furnace for a while and get a mister budddy or something.Thinks for all your thoughts on the matter.I think i will try the camera snake idea soon but for now i think i will just use the furnace for emergencies only.

[D_E_Bishop]

It certainly sounds like a relay or controller with maybe a little dirt between the armature and actuator arm. Does your rig have ducted heat and AC? There may be a door than directs the air flow and is just not quite making it opened or closed. I'd be more concerned with the furnace not working properly than a buzz from some part of the HVAV system. The two could be connected but probably not.

I've not been much help but not being there to see and hear makes it hard to solve a mystery that people who are there can't solve.

[wa8yxm]

My guess is.. To follow

But first a question
What is the make and model of your CONVERTER, and where is it located. IN many RV's (not all) the Converter is part of the Power Distribution Panel Assembly.

IS the Buzzing coming from near the converter?

The guess
Furnace is THE biggest 12 volt load in most RV's (Some it is one of 2 or 3, Macerator Toilet, and 12 volt Absorption Fridge are the other two)

When the Furnace kicks in some converters may "Buzz".

[westend]

Is the furnace blower operating when you hear this buzz? Can you hear the buzz immediately after adjusting the thermostat, before the blower noise is heard?

If the blower is operating, you may be hearing a resonant sound from either the furnace metal or a duct against that wall.

If you hear the buzzing immediately after thermostat adjustment, it may indicate a wiring issue.

I know it would drive me crazy in short order and I'd probably get a look into that space to see what the source is. It could be something as simple as a loose piece of wall insulation that vibrates when the blower engages. I'm guessing the tool for this would be an inspection camera for the least amount of intrusion. Some of these cameras have a small tube so a small hole can be drilled to access the wall cavity.

I'd also rule out the generator as a cause, using a cord to connect to shorepower or another generator.

[joe0508]

time2roll wrote:
Buzzing on a DC circuit sounds like a bad connection.
Are you running on just battery power? Or unplug and see if the buzz continues.

Its running on a 4000 watt onan generator that came with the rv.I have replaced the thermostat with the one on ebay that i gave a description of.I have already had it serviced and cleaned.I had the delay switch checked which is no where near the sound.This is what has been going on before i did all this work and still no help.When i turn on the furnace it does what it is supposed to do.All the way up untill the burner kicks off and the fan just keeps blowing cold air.So i go to the thermostat and turn it up just a hair and i start to hear the sound that i described earlier and the burner kicks back on and all is well untill the next cycle.

[mike-s]

Dual zone heat, 1 furnace? It could be a zone damper is stuck and the actuator is buzzing.

[time2roll]

Buzzing on a DC circuit sounds like a bad connection.
Are you running on just battery power? Or unplug and see if the buzz continues.

[Joe417]

On many rvs, the furnace thermostat also turns on a fan to pull warm air into the basement.

You said it was high on the wall so it doesn't really sound like a fan issue. They are usually in vents into the basement.

[joe0508]

Old-Biscuit wrote:
Sound NOT coming from the thermostat....correct?

Sound is coming from another area....would this be close to where furnace is?

It is probably the 'timed delay relay' in furnace that is buzzing

Its not coming from the thermostat.Matter of fact its not coming from anywhere near the furnace.Let me try and give you an idea of the layout.Its a 92 thor pinnacle by the way.The thermostat is in the back where the bedroom is and the furnace is in the kitchen area.The sound is coming from inside the upper wall close to the ceiling on the passenger side.The thermostat is on the driver side.The only way i can see to get to it is through the wall and i dont really wont to do that.

[Old-Biscuit]

Sound NOT coming from the thermostat....correct?

Sound is coming from another area....would this be close to where furnace is?

It is probably the 'timed delay relay' in furnace that is buzzing