Heat duct in Garage

[The Glampers]

We have a ‘19 394M. Same duct under door of garage as pictured previously.

We’ve camped into the low 40’s at night with a small one sleeping in garage hapijack. Kept door open, furnace and fireplace on and set to 69*f (glamping). To help even out temp we left door open to garage from living room and used the vent fan on low from garage. Maybe 3* cooler in garage.

//chile


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[nbsproducts]

My 351m has a SF-35 furnace with three 4” ducts and one 2” duct installed. One 4” duct runs to a plenum chamber that supplies the front bath and bedroom with a 2” port supplying heat to the storage area. The second 4” port supplies the kitchen register under the kitchen island and the third port supplies the register under the back bath for garage heat.

Very little heat gets to the garage and way too much heat at the bedroom. After reading the installation specs for the SF-35 furnace, it requires a minimum of four 4” ports to be installed and the 2” inch port does not count. (Reference document Suburban Gas Furnaces Installation Instructions Form No 2549-C)

I contacted Dan at Grand Design asking about the installation of my duct work and he did not find the drawing for my unit. So there was no good answer to why only three ports used. I then asked if there was enough room to run a fourth port and duct to the garage register and he said there was. Just go straight as possible because each 90 degree turn takes 20% of the flow. With the removal of the thirteen 1” register in the garage will give enough air flow for the two 4” ducts.

My thought is with adding the required fourth duct, I could add an adjustable register to the bedroom and it would not affect the air flow switch.

Has anyone thought about or implemented this as a solution to the hot bedroom, cold garage?

[orbiker]

My 351m has a SF-35 furnace with three 4” ducts and one 2” duct installed. One 4” duct runs to a plenum chamber that supplies the front bath and bedroom with a 2” port supplying heat to the storage area. The second 4” port supplies the kitchen register under the kitchen island and the third port supplies the register under the back bath for garage heat.

Very little heat gets to the garage and way too much heat at the bedroom. After reading the installation specs for the SF-35 furnace, it requires a minimum of four 4” ports to be installed and the 2” inch port does not count. (Reference document Suburban Gas Furnaces Installation Instructions Form No 2549-C)

I contacted Dan at Grand Design asking about the installation of my duct work and he did not find the drawing for my unit. So there was no good answer to why only three ports used. I then asked if there was enough room to run a fourth port and duct to the garage register and he said there was. Just go straight as possible because each 90 degree turn takes 20% of the flow. With the removal of the thirteen 1” register in the garage will give enough air flow for the two 4” ducts.

My thought is with adding the required fourth duct, I could add an adjustable register to the bedroom and it would not affect the air flow switch.

Has anyone thought about or implemented this as a solution to the hot bedroom, cold garage?

Why not just add an inline 4" helper fan. It would be far easier then adding another duct clear to the back. KEN

[nbsproducts]

Great idea, do they make a 12vdc version? Never mind, found it, plastic hope it don't melt. thanks

[orbiker]

Why not just add an inline 4" helper fan. It would be far easier then adding another duct clear to the back. KEN

Great idea, do they make a 12vdc version? Never mind, found it, plastic hope it don't melt. thanks

It looks like this would be the best on that I could find. Walmart online $19.90 KEN

Marine Boat 12v Electric in Line Bilge Air Blower

[nbsproducts]

Thanks KEN
Parts on order. I'm adding a control relay so when the thermostat calls for heat it will turn on the blower. I'll post the results when finished. May need one for the kitchen also.
Joe

[nbsproducts]

The helper fan or duct booster fan was not an option for installation next to the furnace. The fan was not rated for this kind of heat. Even a dryer exaust fan was not rated good enough for this solution at 150 deg F. Back to the drawing board.

[orbiker]

The helper fan or duct booster fan was not an option for installation next to the furnace. The fan was not rated for this kind of heat. Even a dryer exaust fan was not rated good enough for this solution at 150 deg F. Back to the drawing board.

How do you figure?

If you put the fan inline from the furnace 4 ft away, it's just like a dryer exhaust fan moving the heat / moisture somewhere else.
It's not going to be anywhere near 150 degrees even 4 ft away.
KEN

[nbsproducts]

Hi Ken
I double checked my measurments and at the air box for the duct running to the bedroom is 175 deg F, and at the storage vent about 6 feet away is 169 deg F. When I mounted the inline fan about 3 feet away from the 200 deg port, in 5 min. it started to worp where the fan blades started to rattle againt the fan housing. I don't have room to move the fan any futher than that. I researched an found a $200 dryer fan and called the factory for info on my purpose and here is the quote from them.
Hello,
I'm sure your furnace gets much too hot for this. The heat limit is about 150 degrees F. Thanks for thinking of us.

Chuck Levine
[email protected]

So back to the drawing board.
Joe

[BrokeDown]

Hi Ken
I double checked my measurments and at the air box for the duct running to the bedroom is 175 deg F, and at the storage vent about 6 feet away is 169 deg F. When I mounted the inline fan about 3 feet away from the 200 deg port, in 5 min. it started to worp where the fan blades started to rattle againt the fan housing. I don't have room to move the fan any futher than that. I researched an found a $200 dryer fan and called the factory for info on my purpose and here is the quote from them.
Hello,
I'm sure your furnace gets much too hot for this. The heat limit is about 150 degrees F. Thanks for thinking of us.

Chuck Levine
[email protected]

So back to the drawing board.
Joe

My house had forced air heat, I could restrict the air flow in each run from the trunk. Why not restrict some of the flow to the registers closest to the heater. That would force more to the garage.

-B

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