HYMER WASTE TANK (1 Viewer)

[joeo's]

Hymer 1998, B534 on Fiat 2.5td

Hi All,
I'm trying to resolve the problem of a very slow drain from the shower tray, hand basin, and kitchen sink.
When the waste tank dump handle/valve is open it drains perfectly. Venting issue??
This tank is insulated and located inside another tank/box with polystyrene/aeroboard insulation between the walls of the two tanks. The outer "tank" has a black plastic "inspection" cover on the bottom with, perhaps, 6 screws. This is directly under the dump valve mechanism, I think.
It also has a large circular screw cap in the middle., under the drain cap of the waste tank.

If anyone has removed a similar tank, would you recall seeing any vent pipe system at the top?

I'm now satisfied that the pipes and joints are ok (after much disassembly, cleaning and careful inspection), that the tank is empty and that clear waste pipe entry to the tank is entering a clear empty tank.

So, it looks like it needs a vent, or if has an existing vent, it needs to be unblocked.
If a vent ispresent, .... where. is it?

Any guidance before going at it (lying on the ground) would be greatly appreciated.
Thanks
Joe

 

[pappajohn]

Open the dump valve then pour copious amounts of clean water down the plug holes.

If it drains fast with the valve open it needs venting

 

[joeo's]

Yep, it drains very well when the dump valve is open.

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[Manic]

Hymer 1998, B534 on Fiat 2.5td

Hi All,
I'm trying to resolve the problem of a very slow drain from the shower tray, hand basin, and kitchen sink.
When the waste tank dump handle/valve is open it drains perfectly. Venting issue??
This tank is insulated and located inside another tank/box with polystyrene/aeroboard insulation between the walls of the two tanks. The outer "tank" has a black plastic "inspection" cover on the bottom with, perhaps, 6 screws. This is directly under the dump valve mechanism, I think.
It also has a large circular screw cap in the middle., under the drain cap of the waste tank.

If anyone has removed a similar tank, would you recall seeing any vent pipe system at the top?

I'm now satisfied that the pipes and joints are ok (after much disassembly, cleaning and careful inspection), that the tank is empty and that clear waste pipe entry to the tank is entering a clear empty tank.

So, it looks like it needs a vent, or if has an existing vent, it needs to be unblocked.
If a vent ispresent, .... where. is it?

Any guidance before going at it (lying on the ground) would be greatly appreciated.
Thanks
Joe

Sorry can't help with your problem but I get quite a smell from my B584 waste tank and wondered if I have a vent blocked, so if you find the vent on yours could you please post details.
Thanks

 

[tonyidle]

My B584 had no vent. I solved the problem by removing the bottom cap, drilling a hole in the centre, & using a plumbing fitting to position a pipe just clear of the top of the tank. No mess, no need to remove the insulation or tank. On mine the visible, central, lower cap covered a hole through the insulation through which the real cap could be accessed - just to save the disappointment I felt when I discovered yet another cap to remove .

 

[Manic]

My B584 had no vent. I solved the problem by removing the bottom cap, drilling a hole in the centre, & using a plumbing fitting to position a pipe just clear of the top of the tank. No mess, no need to remove the insulation or tank. On mine the visible, central, lower cap covered a hole through the insulation through which the real cap could be accessed - just to save the disappointment I felt when I discovered yet another cap to remove .

Did you have a problem with smells inside before you did the vent mod, as I haves smell coming from near the wardrobe which comes from where the pipes go into the tank.

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[joeo's]

Thanks Tonyidle.
Did you put a pipe onto the screw cap and then take it up like a U inside the outside tank/box, i.e. between the walls of the two tanks where the insulation sits?

Regarding smells....... In my 534 (U lounge). The waste pipe enters the tank straight down through the floor using an elbow from the pipe that comes from the sinks etc.
The vertical down pipe is about 60 - 75mm long and about half of that goes inside the tank. There is a rubber flange that fits snugly around the pipe to seal it. Unfortunately, I can't remember how the flange is fitted to the tank, but I had a bit of difficulty getting the pipe to go down "squarely" (if that makes sense), so that the seal was a snug fit all round. I remember putting washing up liquid on the pipe and rubber to allow it to glide smoothly in without deforming the rubber seal.
Could this seal be dislodged? Hopefully, access is easy on the 584.
Nice van!

 

[gus-lopez]

Normally the vent pipe will be about 3mm I.D. When you open the 40mm outlet valve the flow will slow as the vent pipe cannot keep pace with the outlet .

 

[joeo's]

Simple fix in the end.
There is enough space to drill a hole in the side of the tank in the B534, using a battery drill.
Drilled an 8mm hole high on side of tank (just under the floor) through exterior plastic "tank", then through the insulation and then through the grey tank.
Pushed a piece of 8mm Copper pipe right through into the inside tank. Tacked the pipe onto the floor with a cable clamp/tie
Opened tank screw cap at bottom and sealed around the entry hole/ pipe from the inside with a dab of silicone on a gloved finger. Probably doesn't need the silicone as pipe was snug fit anyway.

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