Low floor heat air flow

[bobbyl]

Anyone have a heat duct diagram for a suncruiser 38t. The gas heat comes on and stays on but I feel very little heat from any of the floor registers. I can't see anything from under the coach or from under the bed. Am I missing something? The heater does not cut off and will continue to run so I'm assuming the sail switch is functioning as intended. Just very little air flow coming from the vents.

[jesilvas]

Have you gone to the furnace itself and checked the ducts coming off of it?

[bobbyl]

I can't see any of the ducts from the furnace from under the coach or from under the bed.

[Ernie Ekberg]

look under cabinet in bedroom. I believe that is where the return air duct is. It maybe under the bottom drawer and something could have fallen in there. Use a bright flashlite and you will see the hole in the floor. There may be a filter there that is plugged, also.

[jesilvas]

You will not see them under the coach.
Do you know where the furnace is? Go directly to it.

[NeilV]

Originally Posted by bobbyl

Anyone have a heat duct diagram for a suncruiser 38t. The gas heat comes on and stays on but I feel very little heat from any of the floor registers. I can't see anything from under the coach or from under the bed. Am I missing something? The heater does not cut off and will continue to run so I'm assuming the sail switch is functioning as intended. Just very little air flow coming from the vents.

That unit has Basement Air and there should be a flapper that you hear clang when you switch from Air Conditioning to Heat. If that flapper is stuck then it wont flip for the heat resulting in low air flow.

The heat output ductwork should be pretty much a straight shot foward right under the floor in the middle of the coach.

[KIX]

Originally Posted by NeilV

That unit has Basement Air and there should be a flapper that you hear clang when you switch from Air Conditioning to Heat. If that flapper is stuck then it wont flip for the heat resulting in low air flow.

The heat output ductwork should be pretty much a straight shot foward right under the floor in the middle of the coach.

Hmmmmm I didn't know the gas heat and the basement A/C used the same duct system in Itasca

[bobbyl]

they don't. the gas heat comes from the floor, the basement air/heat pump comes from the ceiling vents. I don't hear anything other than the burner light and then the fan comes on.

[edgray]

Originally Posted by bobbyl

they don't. the gas heat comes from the floor, the basement air/heat pump comes from the ceiling vents. I don't hear anything other than the burner light and then the fan comes on.

Are you sure about that. I think the fan MUST come on first and move the "sail switch" before the gas is allowed to flow. While it is running, can you feel the hot exhaust OUTSIDE??? I'm just wondering if the PP heater is actually making heat. I think the fan will shut off after a period of failing to light the gas, and then try again over and over. If the sail isn't allowing gas to flow, you're not gonna get warm. Good luck.

[bobbyl]

I stand corrected, the fan and then the burner lights. I have checked outside and the exhaust from the PP heater is hot and you can hear the burner. It will eventually heat the coach and shut off but the lack of air flow concerns me somewhat. Everything on the system seems to be working normal. No problems with the burner or the fan. I can't hear the damper opening. I don't think I have return air under the cabinets, they all go to the floor and have bottom shelves which would prevent air flow circulation. There is a grill on bottom of the bed that I assume is the return air.

[edgray]

Originally Posted by bobbyl

I stand corrected, the fan and then the burner lights. I have checked outside and the exhaust from the PP heater is hot and you can hear the burner. It will eventually heat the coach and shut off but the lack of air flow concerns me somewhat. Everything on the system seems to be working normal. No problems with the burner or the fan. I can't hear the damper opening. I don't think I have return air under the cabinets, they all go to the floor and have bottom shelves which would prevent air flow circulation. There is a grill on bottom of the bed that I assume is the return air.

Since making heat isn't the problem, then I've gotta think the warmed air must be going somewhere other than into the floor duct. Can you feel any warm air under / outside the coach in the vicinity of the heater itself? perhaps the duct has separated from the heater output. Mine has the heater mounted thru the back cap and it blows straight forward with the single duct running the length of the coach. It does take a while for the warm air to start coming from the front-most floor louvers. If yours is side-mounted, then perhaps air flow isn't as strong due to 90* turn.

FWIW, I think the air return under the bed is directed back to the basement air unit and not to the PP furnace. Since I don't know "how" the PP furnace could receive any return air, have you tried opening a window or roof vent to see if that allows better airflow from the floor vents. Just an idea.
Good luck,
Ed

[NeilV]

The intake is shared with the basment air system. The heater is in the back of the coach right behind the basement air unit and draws from the same air filter with a damper that switches between the units on mine. The blower motor is 12 volts and does not generate a hurricane but more of a gentle flow so when boondocking it will not drain your batteries in the first few hours and force you to run the gennerator to make it through the night.

[Ernie Ekberg]

if you have the grill in the bed, lift the bed and access the plywood that makes up the floor in the bed base. take that up and check out the return hole in the floor

[DancinCampers]

Since the heater operates without rapid on/off cycling, you are getting suffecient return air flow. I would check the front end of floor duct to see if the aux coach heater blower door is stuck open (feel behind the water heater for warm air flow coming out of coach heater core).

On both of my Winnies, the lp furnace return air comes thru a brown grill located on a wall. My 03 Adventurer was located on the wardobe wall under the vanity, on our current coach it is on the bedroom side of the shower wall.

[dsbike]

Did this heater system air flow ever work properly for you? I am assuming this is a new problem.

If all the duct work is connected & the fan is operating properly, then there are 2 factors that can limit airflow. First one is a blocked return vent the second is a blockage in the supply duct.

Find your return vent & be sure it is not being blocked by a new piece of furniture or something that someone may have sat on the floor.

If you find that the return vent is free and clear then next get an inspection mirror , remove a supply vent from the floor and using a flashlight & the mirror inspect the duct work as far as you can see. If you can't see from one end to the other, you may have to remove other vents. I have heard of there being building materials from manufacturer found several years later, also mice building nests, ect, ect.

If you find all the ducts clear then there is this possibility also, My parents 02 Journey was having flow problems & heater cycling problems a few years ago & Suburban figured out that the return vent size was too small. We opened up the floor & installed a larger return vent. This helped with the airflow, but unfortunately did not fix his problem.

[RCVIRGIL]

Just a note on this. I had a problem with low air output from the floor vents when using the propane furnace. The coach heater from the engine uses the same vents (it is actually installed in the underfloor duct) and air flow was great when using the coach heater. Turns out the return air intake under the bed was covered and there was no return air coming to the propane furnace. No return air, no output air. The coach heater air intake was from a different source. So check the return air intake under the bed.