new GMV95 install - combustion air intake connection

[rkgtech]

Hi all and thanks in advance for any help.

My installer just completed my new HVAC install.

The furnace+blower are in a pretty air tight HVAC room. The return duct from the apt feeds into this room and is not directly connected to the furnace return opening.

However, with my previous furnace, the combustion air intake used to be connected with a PVC pipe directly to the unit - here, the installer left this PVC pipe feeding the room and didn't connect it directly to the unit.

Is that a problem or should it be fine?

My electric water heater is also in that room.

Thanks much!

[Atticmonkey777]

Pics might get you more help.

[rkgtech]

Pics might get you more help.

Thanks for your response - please find attached.

[heaterman]

Pic not that great. If you are using the utility room as a giant return air plenum, then not connecting the air intake for the burner compartment to the outside will be a problem. Don't you have a building inspection department in your area. Not connecting the return air to the furnace would flunk an inspection where I'm at.

[rkgtech]

Pic not that great. If you are using the utility room as a giant return air plenum, then not connecting the air intake for the burner compartment to the outside will be a problem. Don't you have a building inspection department in your area. Not connecting the return air to the furnace would flunk an inspection where I'm at.

Ah.. I didn't realise that it would fail the inspection. I am actually not sure of the code in NYC but I can ask my installer - he said that the new GMV95s don't have a place for an air intake - I was a bit suprised since I do see the opening btu deferred to his knowledge.

You are right - the utility room is used as a giant air return plenum.


Thanks

[rkgtech]

Ah.. I didn't realise that it would fail the inspection. I am actually not sure of the code in NYC but I can ask my installer - he said that the new GMV95s don't have a place for an air intake - I was a bit suprised since I do see the opening btu deferred to his knowledge.

You are right - the utility room is used as a giant air return plenum.


Thanks

Does any NYC contractor on this website know whether it is against code please? That would really help me out. Or should I just ask my installer to come back and fix it?

[t527ed]

install instructions i found on line show it as being a 1 or 2 pipe heater.

we have NEVER installed a 90% furnace with 1 pipe, don't want to be sucking contaminated house air through a condensing furnace.......

[rkgtech]

install instructions i found on line show it as being a 1 or 2 pipe heater.

we have NEVER installed a 90% furnace with 1 pipe, don't want to be sucking contaminated house air through a condensing furnace.......

But it is a 95% furnace though.. Goodman GMV950453bx

[t527ed]

But it is a 95% furnace though.. Goodman GMV950453bx


same install as 90% furnaces going back over 20 years.;)

[rkgtech]

same install as 90% furnaces going back over 20 years.;)


OK, I will call him and let him know that it might fail inspection. Is there any danger associated with keeping it this way? To the furnace or to my household?

Thanks much!

[heaterman]

Depending on the pressure differential in the closet, you could end up with nuisance lockouts and in extreme cases, draw CO from the heat exchanger back into the return air and then send it into the living area. This is a life hazard in my book and should be addressed before operating the unit.

[rkgtech]

Depending on the pressure differential in the closet, you could end up with nuisance lockouts and in extreme cases, draw CO from the heat exchanger back into the return air and then send it into the living area. This is a life hazard in my book and should be addressed before operating the unit.

yikes!! thanks much! I will get this fixed right away.

[acguytx]

id like to see pics from the front and sides of this install to get a better picture of what you are talking about..maybe he used one of the pipes for makeup air ??need more info and pics?

[rkgtech]

id like to see pics from the front and sides of this install to get a better picture of what you are talking about..maybe he used one of the pipes for makeup air ??need more info and pics?

Thanks. Right now, there's only one pipe connected to the blower compartment (flue pipe connection). The other pipe is left feeding the room and the combustion air intake connection is not connected. Does this help?

Attached please find pics.

Thanks much!

[acguytx]

wow i dont do alot of 90 plus furnace installs but i do know this how can a room the furnace is in be used as the return air plenum? that doesnt sound right, if that furnace is venting CO2 in this room and the intaller is hoping that it naturally goes up the other pipe and NOt get sucked into the return and put back into the home he is crazy, thats dangerous and is not correct. However if that other CO flue is capped and not venting air, maybe its piped with one flue out one pipe and the other is not being used anymore?

who know but either way have the compnay send another tech/installer to check this out and make sure it was done correctly, however im still confused on how any furncae install would allow the furncae room also be the return?

here the furnace is either in an attic space or closet, if its in an atticc obviously there no return air being drawn from there, not even allowed in a wall chase anymore, hoiwever if its in acloset the door to closet must be adequately sealed from the home so the retun or Cumbustion cannot be drawn from home.

it doesnt make sense so i cant see how thats legal, a warm mechanical room sharing in the return? maybe its backs up to the room but isoalted by a duct for return??

[rkgtech]

wow i dont do alot of 90 plus furnace installs but i do know this how can a room the furnace is in be used as the return air plenum? that doesnt sound right, if that furnace is venting CO2 in this room and the intaller is hoping that it naturally goes up the other pipe and NOt get sucked into the return and put back into the home he is crazy, thats dangerous and is not correct. However if that other CO flue is capped and not venting air, maybe its piped with one flue out one pipe and the other is not being used anymore?

who know but either way have the compnay send another tech/installer to check this out and make sure it was done correctly, however im still confused on how any furncae install would allow the furncae room also be the return?

here the furnace is either in an attic space or closet, if its in an atticc obviously there no return air being drawn from there, not even allowed in a wall chase anymore, hoiwever if its in acloset the door to closet must be adequately sealed from the home so the retun or Cumbustion cannot be drawn from home.

it doesnt make sense so i cant see how thats legal, a warm mechanical room sharing in the return? maybe its backs up to the room but isoalted by a duct for return??

I just spoke with him - he is awesome. He said he would come connect the PVC pipe to the combustion air connection on the unit.

Initially this room had a central air return grille facing the apt. Since it was so loud, now, all the return air is take in from high/low return air registers on closet doors etc, travels through one return air soffit/duct and then feeds this HVAC room. The central return grille is closed and it is a quiet unit :-)

All this within 680 sq ft of my apt (I used to have a 5 ton AC, 120000 BTU furnace)

[MechComf]

Check the installation manual! The vent(exhaust) pipe is to be run with fall back to the furnace. Looks like a horizontal installation. If so vent pipe should be running up then out, with fall back towards the furnace.
Insalled as it is condensate is going to build up in the elbow near connection to furnace and cause nuicance pressure switch faults.
Maybe I'm missing something here.:anyone:

[rkgtech]

Check the installation manual! The vent(exhaust) pipe is to be run with fall back to the furnace. Looks like a horizontal installation. If so vent pipe should be running up then out, with fall back towards the furnace.
Insalled as it is condensate is going to build up in the elbow near connection to furnace and cause nuicance pressure switch faults.
Maybe I'm missing something here.:anyone:

yikes.. i checked the clearance between the furnace and the HVAC room ceiling (it is a low ceiling height room) and there is no room for the pipes to go up and then out.. only about 2 inches or so clearance. what should i do now?? BTW, this flue pipe is also connected to a drain tap which has multiple hoses draining into it.. maybe the condesate would just drain out? no? (please refer to img00007)

There is enough room below the furnace - but to bring the furnace down would involve a lot of work since the supply air duct would be at a higher level than the furnace etc..

[heaterman]

Have your installer recheck the installation manual. The exhaust vent should not go down then back up, unless Goodman has a different idea than all of the brands I have installed. While that furnace is certified for single or dual vent installation, your application MUST be connected with in and out vents.

[beshvac]

I have installed them that way with no problems. Yes the instructions say the supply and exhaust should slope back to the unit but in some installations this is not possible. What needs to be done is the drains off the exhaust need to be trapped (just like the old ultravent installations years ago)

[rkgtech]

I have installed them that way with no problems. Yes the instructions say the supply and exhaust should slope back to the unit but in some installations this is not possible. What needs to be done is the drains off the exhaust need to be trapped (just like the old ultravent installations years ago)

OK kewl thanks - that drain is definitely there and I do hear a lot of dripping :) So, just ask him to connect the combustion air inflow - correct?

Thanks much!

[beshvac]

I can't tell from the pictures how the return is setup, so without being there, I don't know, it depends if the space meets the definition for confined space. If it was my house, I would want it connected.