Calling all HVAC pros

[jjohnsonElknewbie]

Hey guys, a couple years ago I put a steel roof on my house and had them remove the old chimney in the process as my furnace has a power vent. My HVAC guy re-routed the furnace exhaust pipe horizontally out the north side wall (3"or 4" b-vent). Ever since, I've had trouble with the furnace getting blown out by strong NW winds. He said there wasn't much to be done and to try putting a box or barrier in front of the vent. Done.

Last winter the draft inducer motor went out and I replaced it. The new unit is an upgrade from the 1999 OEM version and seems to push more air. However, I'm still concerned about it getting blown out this winter.

So the question is, what is the most effective high wind cap for horizontal b-vent?

 

[Jstumbaugh]

Duravent high wind cap is pretty solid. Your furnace is prob 4".

 

[jjohnsonElknewbie]

Duravent high wind cap is pretty solid. Your furnace is prob 4".

Thank you for the recommendation. It has the Amerivent model that looks like this now. Does this change your suggestion at all?

 

[Jstumbaugh]

I'm surprised that you are getting that much "blow back" with that topper,

This is what we sell. Do you have a very short vent run?

 

[jjohnsonElknewbie]

I'm surprised that you are getting that much "blow back" with that topper,
View attachment 460423
This is what we sell. Do you have a very short vent run?

Thanks again man. The vent run is roughly 2.5' vertical off the furnace to an 90 degree elbow. Then approx. 4' horizontal west to another 90 degree elbow. Then it's about 16' north to the exterior wall. Outside there is about 2.5' of pipe with the cap.

 

[Jstumbaugh]

Your vent run isn't short at all. and normally a north wall shouldn't be taking a prevailing wind continuously. Any chance your blocked vent/ pressure switch is weak and tripping prematurely?

 

[jjohnsonElknewbie]

It's possible, I think it's OEM (1999). The new inducer came with new silicone hose to connect to the presssure switch, and I'm hoping that may help as well. I also cleaned the flame sensors with some steel wool.

I had a heck of a time getting the correct inducer motor as well. I finally found the correct Rheem cross reference table, and it could be that I wont have any issues this year. However, I just wasn't sure if there was a better cap out there for this application. The one you suggested is pretty cheap, so it can't hurt to replace it too and see what happens. First big cold front of the season coming today and our highs will be in low 50s tomorrow with low in the 20s. If we get wind to go along with it, I'll have my answer soon enough!

EDIT: the cap you suggested says only applicable to vertical terminations, darn it.

 

[Stalker69]

Make sure you can vent that bvent horizontal, and that long of a run. Don't sound at all right. Now if it's high efficiency, and vents with pvc pipe you can run it horizontally.

 

[MT_Wyatt]

Make sure you can vent that bvent horizontal, and that long of a run. Don't sound at all right. Now if it's high efficiency, and vents with pvc pipe you can run it horizontally.

Was going to say the same on materials/horizontal. If we’re talking high E PVC venting system, they can take a good bit of direct wind without impact to furnace ops. I see 40mph plus on the prairie and am vented to windward side of the house. Funny part was plumber refused to use a direct vent water heater for fear of issues from wind, meanwhile furnace guy is like “no biggie.”

OP find the install manual for your furnace or call manufacturer to confirm what’s best - if you have a high E furnace, there aren’t a ton of options for termination on horizontal vent.

 

[TaperPin]

Hey guys, a couple years ago I put a steel roof on my house and had them remove the old chimney in the process as my furnace has a power vent. My HVAC guy re-routed the furnace exhaust pipe horizontally out the north side wall (3"or 4" b-vent). Ever since, I've had trouble with the furnace getting blown out by strong NW winds. He said there wasn't much to be done and to try putting a box or barrier in front of the vent. Done.

Last winter the draft inducer motor went out and I replaced it. The new unit is an upgrade from the 1999 OEM version and seems to push more air. However, I'm still concerned about it getting blown out this winter.

So the question is, what is the most effective high wind cap for horizontal b-vent?

Unfortunately, the high pressure on that side of the house isn’t influenced much by a small barrier, or the type of exhaust cap because all the air around the new box is still at the same high pressure from the wind it was before the box. It’s a pressure differential issue unless it’s a high efficiency unit with both intake and exhaust coming out at the same spot. In high wind areas we built vacation homes in I constantly had to go around and around with hvac installers, plumbers, roofers, kitchen exhaust installers, washer/drier guys, fireplace installers and even architects when choosing roof and wall exhaust penetrations. It drives me nuts every time one of these guys wants to vent out the high pressure side of the roof or upwind wall because the back pressure causes fart fan/range hood/drier one way flaps to flutter and make noise, causes problems you’re describing, and you get weird cold drafts with gas fireplaces when aren’t on and improper drafting when they are run.

Hope you find an easy solution.

 

[jjohnsonElknewbie]

Hope you find an easy solution.

I did end up finding the right inducer motor and a better cap, and they helped a bit, but there were still occasional flame outs on the old unit.

We replaced the old furnace and antique central ac last spring, and I've never looked back. We have a 2 stage 98% HE furnace now and it did an amazing job heating the place last winter. I still ran my wood burner during the day before it got too cold to save on propane, and at night I was able to run the thermostat at 65 instead of 60 without running through my contract. The units installed are both Goodman brand and I believe manufactured in the USA.

 

[TaperPin]

I did end up finding the right inducer motor and a better cap, and they helped a bit, but there were still occasional flame outs on the old unit.

We replaced the old furnace and antique central ac last spring, and I've never looked back. We have a 2 stage 98% HE furnace now and it did an amazing job heating the place last winter. I still ran my wood burner during the day before it got too cold to save on propane, and at night I was able to run the thermostat at 65 instead of 60 without running through my contract. The units installed are both Goodman brand and I believe manufactured in the USA.

Oh shoot - I didn’t notice this is a really old thread. Lol

 

[jjohnsonElknewbie]

Oh shoot - I didn’t notice this is a really old thread. Lol

No worries and I appreciate the advice. I can share with anybody that runs into the same issue.