Vacuum Breaker Issue

[Knightly]

I have read all the posts regarding the subject of vacuum breakers however I still do not understand how I can determine which vacuum breaker is causing the problem.
A recent problem is sewer odor after dumping the black and grey water tanks in my 2007 Class A, Itasca Sunrise, 35A. I have been able to locate one vacuum breaker behind the washing machine and another one under my bathroom sink. Would both of these breakers allow air into the grey and black water tanks for venting or only the grey water? Would there be other vacuum breakers hidden away somewhere in the rig? How can I isolate which breaker is causing the problem??

Any suggestion would be appreciated.

Knightly

[DriVer]

Originally Posted by Knightly

I have read all the posts regarding the subject of vacuum breakers however I still do not understand how I can determine which vacuum breaker is causing the problem. Any suggestion would be appreciated.

Knightly, My response is going to be very simple. It is possible to pull the water out of the traps when you are dumping your tanks although it's not something that I have consistently seen. Most often when we travel down the road we might loose the water in the trap and the tank gases may intrude into the cabin. This happens to us most often from the washing machine trap. I have to run the washing machine for just a few moments to fill the trap and no more odors.

[KIX]

Knightly......... go to Winnebago Industries then click on 'resources" then "diagrams & manuals" then look for plumbing diagrams for your coach. You should be able to find the answers to your questions

[RVhauler]

rather than try to determine which breaker might be the problem just replace all. They are around 6 dollars at lowes/Home Depot

[DancinCampers]

There should be another one under kitchen sink.

Only grey water tank I believe, unless one of your sinks, shower or washing machine empties into your black tank.

Running basement air creates negative pressure inside coach, might try keeping it off during dump.

Also, might try setting ceiling fan vents to push air into coach while dumping.

[Knightly]

Yes, there is a third vacuum breaker in my unit, one under the kitchen sink, one under the bathroom sink plus one behind the washing machine according to the Itasca site diagram. I now have several ideas, so I will pursue further. Thanks to everybody for all the advice.

Knightly
2007 Itasca 35A W24

[wa8yxm]

How to figure out which breaker is not sealing properly......

The nose knows... All you can do is sniff it out.... Takes time for the stink to travel so either have your partner sniff while you dump or you sniff while partner dumps.... May take a few dumps to be sure.

[Always-RVing]

Are you guys talking about the air-vents under each sink, etc? They have a rubber waffer that opens up as water rushes down the drain. This stops a vacuum from building up behind the water flow. The air vent is required for each drain that does not have an external pipe running out of the roof.

Check Vent: You can see if they are bad by removing it and holding a flashlight up to it. There should not be any light getting through. You can try cleaning it. Sometimes that works, sometimes it does not.

There are various grades or quality check-vents. Some are very cheap and do not last.

The problem is when they do not close and the rubber flat doesn't seat.

They are easily removed by unscrewing (by hand). Tighten gently.. There's no need to over tighten. If they do not seat properly, foul sewage gasses from your waste tanks will emit from them.

[two-niner]

Batman_777 is on the money.

Also, swimming pool stores sell a waterproof lubricant used in pumps and filters. They help seal the internal flange against air/water passage. I've used it for 25 years.

Kerry