Gas pack vent

Why do HVAC guys use PVC for EXHAUST vents? I had the heat on for 10 minutes and it gets hot! What is the proper material for this?


gaspack vent.jpg

How hot is Hot .
Hot to your hand?
Hot to melt the pipe?
What temp was it?

… Cookie


Hot to hand.


110 is to hot for me others can take 120 for a while .
… Cookie

Can any HVAC wizards tell me if PVC is OK for gas pack exhaust venting?

I am just a old farmer:D and not even a wizard farmer but you are only allowed PVC on high efficiency furnaces and as an HI you can determine this by looking at the drain line set up near the combustion blower should be some rubber or plastic drains connecting to the A-coil drain line.

Gas packs are located outdoors, that is just a gas furnace.

Check the end of the exhaust pipe where it exits the foundation and see if it has a powered exhaust fan. If it has one and is defective and is not wired into the control voltage the exhaust temperature would be too high.

Look at what the manfacture says . They have the last word.
… Cookie

Gas furnace OK

It has NO exhaust blower just a vent see pic also the rise is almost flat (very very little rise) about 15 feet to exit building.

PVC is OK for this Hi efficiency, check with Payne and its OK.

Any thoughts on should it have a exhaust blower

Unit has a blower internally. The external blowers are not necessary.

PVC can handle a substantial amount of heat. 120 degrees is not substantial.

Is the installation manual on site as required should a mechanical code inspector is required to inspect install? The venting materials would be listed in the manual. If the manual is not on site the best source would be to contact the local wholesaler with the furnace model and serial numbers for venting material.

If the vent is getting hot and sagging there is a problem. What was the measured temperature rise of the circulating air. High temp rise could indicate dirty blower, secondary heat exchanger (if this is a 90 percent efficiency furnace), or evaporator coil, also could be overfiring. Best to recommend inspection by hvac company.:wink:

Sidewall venting kits are not required on 90 + percent efficiency furnaces. 80 percent efficiency furnaces vented side wall yes they do require sidewall vent kits.

One thing I did see. Combustion air must be taken from the same zone as the vent exhaust. Carrier/Bryant/Payne/ Day & Night are all manufactured by United Technologies. A company that I formerly worked for sold Bryants and we always ran the combustion air pipe out with the vent. The same would hold true for that Payne. That one the combustion air is being taken from the crawl space.

Good info thanks and it makes sense I will check on this with Payne.