22RKHL gray water mystery

[CamperChiefSteve]

Hi all, I have a mysterious problem with my Salem Hemisphere 2024 22RKHL gray water tank. The tank size spec is 32 gallons and I believe this is a single tank since the bathroom and kitchen are next to each other and there is only 1 drain valve. However the gauge panel has both gray 1 and 2 buttons so maybe there are 2.

After very little water usage (2 showers, light kitchen and bath sink use) plus the spring plumbing flush the gray 1 tank shows full and gray 2 empty. Then during a shower water bubbles up from the kitchen and bath sinks and the bath sink no longer drains completely. But the shower drains fine. Nothing leaking anywhere. Gray 1 gauge says full and gray 2 empty.

Maybe there are 2 tanks but they are somehow connected? Must be some pressure in the tank to keep the bath sink from fully draining. I filled the bath sink up and then pulled the plug, got some gurgling from the kitchen sink but no water coming up.

Are the tanks vented to atmosphere somehow? Wondering that if that is the case maybe this is blocked.

Any ideas on what the problem could be?

Thanks
Steve

 

[Aussieguy]

Bath sink can sometimes be connected to black tank

Shower drain and kitchen to gray tank

Make sure black tank and gray tank selector valves are turned off

Because they can allow mixing of the tanks when the main empty valve is closed

 

[CamperChiefSteve]

Both selector valves are closed, there isn't a single main valve.

I think the gray tanks must mix when they join at the single drain, but if they aren't vented they can't mix efficiently.

When I get back home I'll do some testing to see what's connected to each tank.

 

[fipntdot]

I don't know your unit. Our camper's panel has Grey 1 and 2 monitors but no second tank. They simply used a panel that could handle a second grey tank if needed.

I assume the rv is totally level? The fall on our grey line from shower to tank can get disrupted if we are too high in the front. It seems odd the shower still drains but the sinks have trouble. Often the shower is the first place water backs up with a full tank.

 

[Aussieguy]

food coloring helps trace tanks and drains

 

[CamperChiefSteve]

Did some testing today to check drainage and tank sizes.

Our unit is spec'ed at 32 gallons of gray water storage.

Kitchen, bathroom sink and shower are all connected to same gray tank.
Gray 1 gauge shows full at about 16 gallons, Gray 2 gauge always shows empty.
After gray 1 shows full, adding more water causes backpressure into both the bathroom and kitchen sinks. After enough pressure builds it blows out the water in the traps but it will drain. Trapped air did not blow out through the shower drain, only through the sinks.

Tested to over 30 gallons draining into shower and kitchen sink in two separate tests so appears to have around the 32 gallon rated capacity.

My theory is that there are two 16 gallon tanks. The second tank may be some sort of overflow from the first and is not vented properly and the gauge doesn't work.

Anyone else seen anything similar?

Contacting FR to get their feedback.

 

[bikendan]

I would contact the Salem division directly, not FR customer service.

 

[Aussieguy]

If your sinks don’t flow freely
Something wrong with the tank / drain venting system?

If I suspected I have 2 tanks I would just leave them both open so they act as one tank all the time.
As long as they are plumbed together to share a common outlet.

 

[Oaklevel]

As has been mentioned the panel indicator marked grey 2 may not be used as the panels are used in several models........ The water system is vented through the roof.

As also been mentioned you may want to contact the Salem / Wildwood Division for more info. not Forest River.