Operation of Intertherm downflow furnace.

deerslayer · 11-30-2009, 07:56 PM

I have an Intertherm downflow furnace in a vacation home i just purchased. I'm a Handyman, but not real good with HVAC. Furnace works great. Question is: The ductwork that comes out of the top of the squirrel cage that is mounted on top of the furnace. Is that an intake, a vent pipe or what? They ran it into the attic but it doesn't come out of the roof. Is this okay? It doesn't get hot like a flue. Wouldn't think if an intake it should be outside the roof because then you would be trying to heat ( let's say 10 deg. air.) Edumacate me please.

Wildie · 11-30-2009, 08:09 PM

Quote:

Originally Posted by deerslayer

I have an Intertherm downflow furnace in a vacation home i just purchased. I'm a Handyman, but not real good with HVAC. Furnace works great. Question is: The ductwork that comes out of the top of the squirrel cage that is mounted on top of the furnace. Is that an intake, a vent pipe or what? They ran it into the attic but it doesn't come out of the roof. Is this okay? It doesn't get hot like a flue. Wouldn't think if an intake it should be outside the roof because then you would be trying to heat ( let's say 10 deg. air.) Edumacate me please.

My guess would be that this 'return air' from or via the attic!
You should look up there and see where it goes!
A photo would make it easier to say!

SPS-1 · 12-02-2009, 05:22 PM

See Link http://www.intertherm.net/common/MHGF.htm#1040067
If its the M2RL series downdraft furnace, the literature is pretty good.
As Wildie said, a picture would help, but I think you are looking at the combustion air intake. I once asked a furnace technician about bringing in combustion air from outside to my Intertherm ( it should be a crime to use indoor air for combustion) , and he said I could not directly connect a duct to the furnace combustion intake, but I could bring in a fresh air duct and terminate it a few inches above furnace combustion air intake. This may be what was done on your furnace. I am not sure if an attic is an approved place to get combustion air, but if your duct is not directly connected to the furnace, it may be OK. ( you refer to squirel cage, which makes me think you are looking at the wire mesh overtop of the standard intake)

deerslayer · 12-02-2009, 07:02 PM

Quote:

Originally Posted by SPS-1

See Link http://www.intertherm.net/common/MHGF.htm#1040067
If its the M2RL series downdraft furnace, the literature is pretty good.
As Wildie said, a picture would help, but I think you are looking at the combustion air intake. I once asked a furnace technician about bringing in combustion air from outside to my Intertherm ( it should be a crime to use indoor air for combustion) , and he said I could not directly connect a duct to the furnace combustion intake, but I could bring in a fresh air duct and terminate it a few inches above furnace combustion air intake. This may be what was done on your furnace. I am not sure if an attic is an approved place to get combustion air, but if your duct is not directly connected to the furnace, it may be OK. ( you refer to squirel cage, which makes me think you are looking at the wire mesh overtop of the standard intake)

I'm sry, the referral "squirel cage" is what I call the blower fan which sits directly on top of the furnace and is open on one side so u can see the fan blades. This duct mounts on top of the blower fan and goes into the attic. The door on the front of the furnace which encloses the furnace has wire mesh in it and I think it gets the combustion air from here and enters the blower fan. I can't figure out if the pipe going to the attic is a "fume vent". The fumes and heat rising from the pilot when the furnace hasn't kicked on has to go somewhere. I'm just wondering if I need to extend this pipe thru the roof or will it just vent the fumes out thru the gable vents at the ends of the roof. I'm concerned if this is a fire hazard.

Wildie · 12-02-2009, 07:33 PM

Quote:

Originally Posted by deerslayer

I'm sry, the referral "squirel cage" is what I call the blower fan which sits directly on top of the furnace and is open on one side so u can see the fan blades. This duct mounts on top of the blower fan and goes into the attic. The door on the front of the furnace which encloses the furnace has wire mesh in it and I think it gets the combustion air from here and enters the blower fan. I can't figure out if the pipe going to the attic is a "fume vent". The fumes and heat rising from the pilot when the furnace hasn't kicked on has to go somewhere. I'm just wondering if I need to extend this pipe thru the roof or will it just vent the fumes out thru the gable vents at the ends of the roof. I'm concerned if this is a fire hazard.

A greater danger would be that carbon monoxide ( CO ) would be vented into the attic!
All furnaces need ventilation and if yours is vented into the attic space, it would be a major problem.
CO is heavier than the air we breathe so it would seep down into the living quarters. WITH FATAL RESULTS!
The nature of your query leads me to believe that you are unfamiliar with the operating principals of combustion furnaces.
I would advise you to have a qualified furnace technician come in, check out your furnace and explain how yours works!

deerslayer · 12-03-2009, 08:13 AM

Quote:

Originally Posted by Wildie

A greater danger would be that carbon monoxide ( CO ) would be vented into the attic!
All furnaces need ventilation and if yours is vented into the attic space, it would be a major problem.
CO is heavier than the air we breathe so it would seep down into the living quarters. WITH FATAL RESULTS!
The nature of your query leads me to believe that you are unfamiliar with the operating principals of combustion furnaces.
I would advise you to have a qualified furnace technician come in, check out your furnace and explain how yours works!

Like I said in my initial thread, I'm not an expert with HVAC, that's why I'm asking for help. Ur right, have a tech come in and check everything out would be the best solution. Thanks for the input.