Shower not draining

[GLM1000]

I have a 2016 Thor Venetian M37. The shower is not draining. The grey water tank was half full so I drained the tank and the water immediately drained from the shower. However, I ran water in the shower again and it’s not draining. My thought is the vent line is plugged? If so where is it located?
Thanks!

 

[16ACE27]

The gray tank is vented on the roof but most showers are not and have no "trap". They use a "check valve" type trap. It may be hung up or need cleaning.

 

[GLM1000]

I found the “check valve” vent cap for the sink in the room with the shower but it works fine. Does the shower have its own check valve vent cap and where might it be located?

 

[16ACE27]

I found the “check valve” vent cap for the sink in the room with the shower but it works fine. Does the shower have its own check valve vent cap and where might it be located?

That's called an Air Admittance Valve (AAV).

The drain in the shower is the check valve for the shower.

 

[GLM1000]

The drain is permanently fixed to the shower base. How do I get to the vent check valve?

 

[16ACE27]

A lot of RVs have a removable panel in the wheel well that provides access to the shower drain plumbing.

 

[GLM1000]

I pulled the furnace duct and can see under the shower base. No vent of any kind that I see.

 

[GLM1000]

Disregard my last post. Sorry.
The shower drain does have a goose neck but I do not see the vent line. It must go through the roof downstream of the goose neck before going into the tank.

 

[ghnl]

An inexpensive endoscope camera might allow you to see down the drain and search for a blockage. There are some cameras that connect to a smart phone.

Remove the P trap (put a shallow pan underneath to catch any water that will spill out). That is the most likely place for a blockage.

 

[16ACE27]

Disregard my last post. Sorry.
The shower drain does have a goose neck but I do not see the vent line. It must go through the roof downstream of the goose neck before going into the tank.

Re-read post #2. And your shower has a regular P-trap, not the check valve drain.

 

[Lt Keefer]

Almost all of us loose hair during a shower, check for a fur ball stuck in the drain.

 

[Jimbo57]

Almost all of us loose hair during a shower, check for a fur ball stuck in the drain.

I have a 2016 Thor Venetian M37. The shower is not draining. The grey water tank was half full so I drained the tank and the water immediately drained from the shower. However, I ran water in the shower again and it’s not draining. My thought is the vent line is plugged? If so where is it located?
Thanks!

With a trap like that would a small snake reach in and grab what’s maybe blocking it. Like the hand crank with 1/4 “ spring wire

 

[Richard-THOR]

I found the “check valve” vent cap for the sink in the room with the shower but it works fine. Does the shower have its own check valve vent cap and where might it be located?

I have the same coach…. Also same problem but intermittent. When at campsite I keep black tank closed an grey tank open. If black tank becomes too full (like more than 2/3) seems to make problem worse.

There is some type of valve on the sink drain. Believe it is to allow air into drain, but don’t know. There is not a vent line that I can find.

Have had problem checked at CW and other service places. No luck.

Let us know if you find a solution.

 

[Chateau_Nomad]

Two primary causes of drain "clogs": A physical clog, like a huge hairball blocking the pipe, OR a venting problem... which mimics a physical clog.

For a physical clog just snake the drain or use pressurized air.

For a drain to work properly it MUST allow air in, or you get the effect of a straw holding water. Either you have a vent pipe connected to the drain pipe which extends vertical through the roof, or you have an air admittance valve. Air admittance valves can stick closed not allowing air in. A "burping" drain is an obvious symptom of venting issues.

Many times the shower is directly above the gray tank and the plumbing doesn't require a vent... the run is so short that the tank vent is all it needs. However, sinks nearly always need a vent... look under your cabinets for an online air admittance valve and see if it's stuck closed.

 

[GLM1000]

I have an AAV for each sink (I have 3). All of them are working. According to the plumbing schematic from Thor the grey water tank does not have a vent line but the washing machine and black water tank has a vent line through the roof.
If we use the short with the grey water tank valve closed the shower intermittently will not drain.
The shower had about 1” of standing water in the pan. I opened the vale and drained the grey water tank (about half full) and the shower drained rapidly. So the drain line is not plugged.

 

[dkoldman]

Are you able to log on a Thor website or call Thor to get a plumbing drawing similar to the below. In my case no p trap , no AAV etc, but it does vent up through the roof.

 

[GLM1000]