[rockadanny]

The dufus who installed my HVAC system in the attic did not consider being able to change out the filter, as it is mostly blocked by this 2" PVC pipe.
I can pull out the old filter by twisting it all up, but unable to put in a new filter unmangled as this pipe is in the way to properly fit it in.
Unsuccessful getting the HVAC guy to return my calls to reconfigure the HVAC system, so I was wondering if I could just reroute this 2" PVC pipe, enough to get a new filter into the HVAC system?

I think this 2" PVC pipe is just for venting plumbing. Yes?

If so, does it matter if I add a couple more 90^o elbows and extra pipe to it so I can have clearance to install HVAC filter?

[Peter J]

It's probably a plumbing vent if not connected to air handler somehow. Modern high efficiency HVAC can have one or two 2" vents for exhaust and/or combustion air intake, (direct vent).

If it's a plumbing vent the real requirement is that it continuously slopes to so that any water that enters from above roof (I assume), that water will drain into sewer or septic. Maybe you could jog it horizontally around filter access.

A photo might be helpful and I could better advise.

[rockadanny]

@Peter J - Seems to come from laudry room ceiling and possibly a bathroom ceiling, then out thru roof.
NOT connected to HVAC at all. Just runs in front of it.

[mikeeastman]

I've never seen a vent pipe run that far horizontal before, don't think that's right I'd go up using a series of 45s starting before the heater up to the roof.

[Peter J]

I think you're right, it appears to be a plumbing vent. I assume filter is behind the cover on air handler? I suspect jogging it out would be easiest, just avoid creating low spots in piping.

Curious as this sounds like it was recently installed, but that's not a high efficiency unit. I can tell by the conventional exhaust vent.

To Mike's point. Different areas of the country have different codes. Fewer roof penetrations mo' betta IMHO. Air doesn't behave like liquid. It could be run in loops but for the low spots created. You could run higher in attic and attach higher on main stack if that looks like a better plan.

[rockadanny]

Thanks guys. And no, it is not a high-efficiency unit.

[rockadanny]

Filter is on the right side of the unit. So must be able to slide in length-wise from the front, but lower than what the pipe allows.

[Phil A]

Is it the drain line where water leaves and goes outside the house?

[rockadanny]

Don't think so since goes up thru roof.

[WGH]

The plumber probably ran the vent that way to use an existing roof jack.

Cut the PVC in two places on each side of the HVAC and make a "U" big enough so the filter can easily be replaced.

The next person to buy your house will see the Rube Goldberg piping and say "what the heck?" until they need to replace the filter.

[rockadanny]

Good. Thank you.
 

[rif]

The plumber probably ran the vent that way to use an existing roof jack.

Cut the PVC in two places on each side of the HVAC and make a "U" big enough so the filter can easily be replaced.

The next person to buy your house will see the Rube Goldberg piping and say "what the heck?" until they need to replace the filter.

I may be thinking of something else (maybe i the intakes/exhausts on hi efficiency units),but doesn't the vent require a continously sloped run?  I mean no ups and downs, like the U thats being suggested.  Otherwise it could work like a trap.

[JLM]

Looks like a vent pipe, in which case should be sloping up all the way to the roof.  Long horizontal runs (as shown) is undesirable.  "U" shaped redirect would render it ineffective as a vent.  I like the 45 degree idea.  And i'd be adding more insulation (here in Michigan we had 15 inches of blown cellulose installed) to create an EPA 5 star home.

[WGH]

"U" shaped redirect would render it ineffective as a vent.

Why? Farts don't go around corners? Just asking, I'm not a plumber.
A slope would be nice so rain water and small animals flow downhill. Or put a vent cap cover on the pipe to keep all that rain and stuff out.


Plan B:

Cut off the PVC where it comes into the attic and install a Air Admittance Valve (AAV)
https://www.oatey.com/faqs-blog-videos-case-studies/blog/3-things-you-should-know-about-air-admittance-valves

Seal off the top of the existing PVC.