Tank Odor

[trvlngnrs]

> The Bird sometimes has tank odor, and other times no tank odor
inside of the coach.

Curt, I don't know if BB uses the valves, but Newmar has valves in the
bathroom, under the sink that can stick open and allow the holding
tank odor in the rig. Here are some posts reagrding this valve from
the Newmarowners forum on Yahoo.
Steve Harrie
St. George, UT

Subject: Re: Strange White Undersink Valve in Water Lines/Smells
>The valve is behind the drawers, located quite high, and installed
between two lines which have the same appearance as water lines.
There are two pipes and there is a directional flow arrow on one valve
fitting. The gravity weighted one-way valve inside appears to restrict
flow to the bottom fitting, but not the side fitting. The side
fitting appears to be vented to open air through the top of the valve.
I also noticed that the valve has some markings: 110 degrees F & 125 PSI.

What you are calling the very strange looking valve is the anti back
flow valve in the line that goes to your black water tank flush
system. It keeps stuff from backing up to the connector where you
attach your hose to flush your black water tank.

I have replaced my valve twice. If it sticks open you get a terrific
odor. Check message #30212 for a solution which has worked for me.

I too have been plagued by smells at one time or another. The
anti-siphon valve under the sink in the bathroom is for the black tank
rinse (I believe). I have checked and rechecked this valve. I have
removed it, bypassed it, and replaced it. All with no positive
results. I have determined that somehow I have a leak or improper
seal in one of the tanks that causes fumes to occur in the basement.
When I turn on the Fantastic Fan in the bath area. I can feel air
rushing in from under the sink cabinet. This air coming in is smelly!
I think eventually I will foam the area around the hoses and pipes
that penetrate the flooring and this will keep the smell in the
basement. The next step is to find the exact source of the smell.

There is a one way vent under the sink, which is called a vacumn
breaker, I believe. It breaks the vacumn caused by water rushing out
of the sink and allows the sink trap to retain water, for odor control
purposes. I tried taping the vent shut, and filling the trap with
water prior to moving, but that didn't seem to help.

1. The valve under the lavy sink is for the black tank. 2. You have a
mechanical vent by each sink drain line. It unscrews and is 1 1/2 inch
diameter. These can be covered or wrapped with a ziplock bag and
secured with a rubber band. 3. The location of the roof vent does not
make a difference. The refer is sealed from the inside. 4 If you have
any roof vent open while traveling and one of these vents is close to
the gray roof vent you may have pulled in the odor since you have a
vacumm in any RV while traveling. Unless you open some windows and
equalize the pressure. Make sure the washer dryer prep drain pipe has
water in the P-trap. Put water down the tube and then seal to top.
Brent

Subject: DSDP '01--Odor under bathroom vanity
The drain line for the washer and sink(that is at the bottom of the
cabinet) has a "valve" that seems designed to allow air to enter the
line to expedite drainage when the washer empties. Air enters the
line through a rubber diaphram which I think is designed to allow
airflow in only one direction. The problem is that we seem to be
getting gray water odors that that backup into the vanity.

I was in a location where I couldn't easily get another valve, and I
managed to get mine to work again. The valve is a combination
anti-siphon air inlet and one-way sewer flush water valve. The
one-way valve can get stuck if you run water quickly into the valve.
We did this when we flushed our black tank using one of the campground
water valves that has a handle you lift (they're used in areas that
freeze). Lifting the handle instantly turns the water on, and
initially air is in the hose, and the air can travel quickly through
the small Newmar valve. When the water hits the valve there is a lot
of momentum, and the one-way water part of the valve can travel
further than it is designed to travel, and get stuck. After we got
ours unstuck, I've only turned the sewer flush water on slowly, and
haven't had a problem since. -- Daryl Daughters

I think the valve is called a "vacuum break valve". Lets air in but not
out when it is not stuck or broken. Lowes, Home Depot would have them.
Works on the same principle as a straw full of water with you finger
over the end. The water fill not drain out until you remove your
finger, thus breaking the vacuum. Also, before I blamed the under sink
vacuum valve I would go to the roof and check the air vent. The roof
air vent may be blocked thus forcing gasses out the vacuum breaker
valve. You can just take a water hose on the roof and run water down
the air vent. It goes directly in the holding tank. Tom Nagy

Does the sewage odor only appear after you have driven down the road
for several hour? Does it abate after you have sat in a campground
for several days? If you answer yes to the above questions it is most
likely the anti-siphon/backflow prevention valve in the black tank
cleaning system. Usually you will have to remove the drawers to see
this valve. There are two valves under the sink. The first one that
you mentioned is an anti-siphon valve that, usually sits on top of a
short riser, on the drain line from the sink. You can isolate this
valve by either removing it and replacing it with a solid cap or the
easier and cheaper method is to wrap it in Saran Wrap and either
rubber band or tape the bottom around the riser pipe. If this does not
eliminate the problem then most likely it is the anti-siphon/backflow
prevention valve in the black tank cleaning system. I don't know which
anti-siphon/backflow prevention valve that you have in the black tank
cleaning system. If it brass with a, most likely, gray fitting coming
out of it horizontally then what you need to replace is that little
gray valve. They can also be repaired. The problem is, like Daryl
mentioned, due to a large rush of water/air there is a little o-ring
that gets moved out of position. If you unscrew the valve. Take a
small rod and insert it in one end of the valve. Then push and open
the valve. While holding it open use a tooth pick or somethin similar
and reseat the o-ring underneath the little plunger. Put it back
together and you should be off and running.
If the anti-siphon/backflow prevention valve is one piece I cannot help
you. But I would suggest removing it and looking in the horizantal
attachment end and see if it would appear as describe above and maybe
you can fix it.