Gas Furnace: Maintenance

[Batman_777]

We have two gas furnaces: 20k BTU and a 25k BTU. Both are forced air.

With cooler temps coming on next month, I wanted to make sure the furnaces are ready for use.

I don't see any filters to change or clean. How do to the units keep from clogging up with dust. As you know, the inside of a MH is a dust magnet. I have to clean the AC filters and fans all the time.

Does the gas furnace burn up airborn particles before it gets to the blower?

I pulled a couple hoses off to see if all looks good... Looks okay..

[ga traveler]

The first time you use the furnace It will burn off the dust. There might be a slight smell for a minute, but it will not hurt anything.

[George Z]

Airborne pollutants inside your unit are merly recirculated with the heated air. Most furnaces do not have an air filtering system. If you search this forum, several members have come up with some very innovative ways to create a filtering method for their furnace.

[Batman_777]

How does the blower stay free of accumilating dust and dirt build-up? Is it a squirrel cage type or round fan? I think this is the unit.. Pretty standard Atwood... Very Common.

Found it... There are two squirrel cage like wheels. One for the air movement and one for the combustion.

Blower Wheel
Combustion Wheel

They do need to be cleaned. But.... I don't see how to get to them. I'll contact a local Atwood service center. The manual states the blowers do need to be cleaned yearly.

[George Z]

Usually a squirrel cage on one end of the motor shaft for heating air and a smaller one on the other end for combustion air. Dust will build up on the heating air squirrel cage after time, I just remove heater to clean every several years as it tends to affect the air movement after a while.

[Cougarkid]

They are squirrel cage fans.

Skinny one feeds air to the burner/heat exchanger.
Fat one draws inside air over the heat exchanger and then pushes it into the coach.
Only maintenance is making sure there are no mud-dawber nests inside the burner/heat exchanger. Those will be an issue.

I had to take one of mine out and tear it after I bought itto get all the nests out. It had been sitting for a while. I swear I got 2 cups full of nests out in the end. Bought screens after that.

[Batman_777]

Quote:

Originally Posted by George Z Usually a squirrel cage on one end of the motor shaft for heating air and a smaller one on the other end for combustion air. Dust will build up on the heating air squirrel cage after time, I just remove heater to clean every several years as it tends to affect the air movement after a while.

I wasn't sure about removing the unit with the gas lines, hoses, etc.

[wa8yxm]

I won't talk about air path but you should check the burner, clean if needed and check the ignition points... My furnace failed one cold day last spring... We had a chilly night being as we had only limited electric to play with.

Next morn I pulled the burner and checked the point spacing.. over 2x the specificed per the owner's manual (Which by the way I had in my hand) Re-set and it's worked fine since.

I have worked on two furnaces that had this issue of not always working.. The other one was the same problem only closer to 4x thn 2x.. IT was in a stick house and oil fired. Again it worked fine after ajustment and again I did the adjustment with the manual in hand.

[Gary RVRoamer]

You can get access to the fans without removing the unit from the RV. Just pull off the outer cover and, on the circulating fan side, an inner cover over the squirrel cage.

I doubt if dust will be a problem, but it doesn't hurt to check.

insect nests in the outside air intake & exhaust and rust scale in the burner tube are the two main things to watch for.

[Batman_777]

I pulled the outter outside cover off two units, and the blower assembly was easily accessible. It was right there in full view. Right behind the outside cover.

To my surprise, it looks quite clean and does not need anything.