Plumbing tank vents

**ItchinToGo!** · 02-08-2021, 08:02 PM

I only see one tank vent on the roof of our newly purchased 337RLS. Are all of the tank vent lines plumbed into one through the roof vent?

**Canyonlight** · 02-09-2021, 07:48 AM

Originally Posted by ItchinToGo!

I only see one tank vent on the roof of our newly purchased 337RLS. Are all of the tank vent lines plumbed into one through the roof vent?

Correct - it has been this way since day one of many GDRVs - our 303/other 303s and 337s where the tank layout and plumbing sinks, showers, etc. allow such. I thought I had a picture to share but I do not. You can remove your basement panels and check your 337 at some point.

Dan

**Calbar** · 02-09-2021, 08:24 AM

Originally Posted by ItchinToGo!

I only see one tank vent on the roof of our newly purchased 337RLS. Are all of the tank vent lines plumbed into one through the roof vent?

Some of the tanks due to layout will be vented with a mechanical vent under the sink like the link below if there is no way to get the vent to the roof. The kitchen Island is a good example of this.
https://www.lowes.ca/product/air-gap...E&gclsrc=aw.ds

Rob

**Canyonlight** · 02-09-2021, 10:11 AM

I located my pictures. It is difficult to see but you can see the third pipe on the left which vents the kitchen sink to the one roof vent. The other two pipes are the vent pipes from the black and shower/bathroom sink grey tank. They all 3 merge into the one roof vent.

Also attached are pictures of the AAVs (Air Admittance Valves) referenced by Rob in his post #3 as well as Janice from GDRV as noted in the next sentence and why they are used as well as the roof vent. One AAV is under the bathroom sink and the other is under the kitchen sink in our (and your) island. These white studor valves (better quality) are replacements of the original black ones installed by GDRV at build which failed for a number of us owners over time.

Here is also a thread and txt copied and pasted covering this in the early days from Janice who was our first direct contact on the forum with GDRV

https://www.mygrandrv.com/forum/show...ght=admittance

All black and grey tanks are vented through the roof. The valve under the sink is an air admittance device (ASTVD = anti-siphon trap vent device) which draws air in when water is draining to slow the process so the p-trap is not completely void of water following the drain process. This valve has a diaphragm that is closed when not draining. Grey tank odors are generally associated with a dry p-trap or a bad diaphragm in the ASTVD.

Best regards,
~ Janice

Dan

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**ItchinToGo!** · 02-09-2021, 10:32 AM

Thanks for the reply's everyone. I haven't had a chance to remove the basement panels yet and look around. It's been too cold here, -16° this morning, and not looking any better for the rest of the week!

**Laceycamille212** · 01-29-2023, 12:06 PM

Hi!

We have a 2018 GD Imagine 3170bh and have been having issues with sewer smell! We replaced the AAV under the bathroom sink. The smell seems to be coming from under the kitchen sink but we don't see an AAV under there. Does anyone know if it has one? Or what it looks like? Would replacing the roof vents help with smell? Attaching pics of the plumbing under kitchen sink and of roof vents. Thanks!