Can anybody help explain what's going on with my 'fresh' water tank system?

[T25Hugh]

Hi! Spoke with the previous owner of our new (to us!) T25 and he said he didn't use the built in under slung 'fresh' water tank because "the water was all brown". Having read through a number of posts on the subject here I can understand why. It's fairly obvious that if water is left for any time it becomes stagnant and unusable and that the system needs to be flushed through but here's where I'm stumped! Having no knowledge in this field how do I do that exactly? I've read about 'a tap' (that needs turning 180 degrees) and that the filter will need changing but I can't see any evidence of said tap nor filter. There's the pipe that runs from the cap lock inlet on the side of the van to the tank itself and there's a (smaller diameter) pipe that i THINK is the connection for the water pump (situated inside the bus under the seat but with loose, unconnected  '+' & '-' wires!) then there's what I presume to be the outlet valve (visible from the side of the tank below the sliding side door) however this outlet point appears to have been painted over with underseal from the looks of it! (There is no visible thread that I can see - it's a ll 'gunked up'!) Can anybody perhaps shed any light as to what might be going on here? We'd really like to get our van's water system up'n'running if possible. Attached are photos of the tank in question that might help explain better what's going on with the system (or, more accurately, what's currently NOT going on with it!) Thanks in advance for any insights. We're looking to get away in our bus for the first time soon but would like to have this sorted before heading out. Thanks for reading! 
 

 

[Brick]

Hi, just after this disc,which I assume is a filter or non return valve?, I have a connector which has a drain valve on it. If the outside gunked up circle was originally a screw in/out plug it would have surely left an inch of stale water behind? I would undo the hose at the point it meets the tank and give it a thorough flushing with a hose pipe, and consider totally renewing the hose at the same time.

[Oldiebut goodie]

Personally I would drop the tank to give it a good internal clean and renew all pipes/wiring etc., likely to have been in place for 30 years and well overdue for renewal. 

[jrt]

As above. I took both our tanks off last year and when I got a look at the water pipes and the metal inserts they were in a right rusty mess.
David.

[T25Hugh]

Thanks for your insights, much appreciated. I think I'll try the hosepipe flush option first and go from there - THANK YOU!

[Piratepete]

Hi.
I have a 1990 Holdsworth Villa 3 Conversion.
Your tank looks the same as mine. Where you've got a disc in the side, I've got a plastic drain tap moulded onto the tank - very useful for flushing the tank and needed at the end of the season to drain the tank. I suspect you used to have one!

The disc unit  on the outlet pipe is probably a non return valve. I have one at this location, but different design - it's about an inch long and only about 3/4" in diameter. There is no filter in my system. From the valve the pipe goes directly to an electric pump under the back seat and thence to the sink. There is a footswitch.

There should be wiring from the tank for the water level gauge. I have one as part of the ZIG control panel. It works well. The supply for the pump comes from the Zig panel.

My tank hadn't been used for years either. I only had to replace the fill pipe which was peppered with holes from road chippings! I did a lot of flushing before I used it. Otherwise all worked. Oh, and there is an overfill valve at the top of the tank.

If you go into Wiki, section 16.2 you'll find a Holdsworth Villa wiring diagram.

When I fill the tank, I always add a couple of capfuls of Aquasol to keep the bugs at bay.

Hope this helps.
Pete

[Aidan]

should be a drain down tap in the hole that is blanked off 

[T25Hugh]

Hi.
I have a 1990 Holdsworth Villa 3 Conversion.
Your tank looks the same as mine. Where you've got a disc in the side, I've got a plastic drain tap moulded onto the tank - very useful for flushing the tank and needed at the end of the season to drain the tank. I suspect you used to have one!

The disc unit  on the outlet pipe is probably a non return valve. I have one at this location, but different design - it's about an inch long and only about 3/4" in diameter. There is no filter in my system. From the valve the pipe goes directly to an electric pump under the back seat and thence to the sink. There is a footswitch.

There should be wiring from the tank for the water level gauge. I have one as part of the ZIG control panel. It works well. The supply for the pump comes from the Zig panel.

My tank hadn't been used for years either. I only had to replace the fill pipe which was peppered with holes from road chippings! I did a lot of flushing before I used it. Otherwise all worked. Oh, and there is an overfill valve at the top of the tank.

If you go into Wiki, section 16.2 you'll find a Holdsworth Villa wiring diagram.

When I fill the tank, I always add a couple of capfuls of Aquasol to keep the bugs at bay.

Hope this helps.
Pete

That's a great help Pete, thanks SO much for taking the time to explain. That puts things into perspective for me where all this is concerned. Seems like I'm missing parts then. I wonder whether it's still possible to source the plastic drain tap you have on your Villa Failing that, do you think if I release the jubilee clip to the smaller diameter hose (for the water pump, right?) that I could just flush the system through with a hosepipe that way instead perhaps? I have an Auto-Sparky coming to look at my electrics later on in the week. As part of the list of to-do jobs, he's gonna hook up the water pump for me (which is currently disconnected below te back seat). It would probably make sense for me to try and flush the tank through first. (The previous owner informed me that, when it 'worked', the water was brown!)

[T25Hugh]

should be a drain down tap in the hole that is blanked off 

Ahh! Thanks Aiden, yes that makes complete sense. I wonder why it was blocked off? There's no record of this in the 'War & Peace'-sized vehicle history tome that came with the van.

[Piratepete]

Hi.
I have a 1990 Holdsworth Villa 3 Conversion.
Your tank looks the same as mine. Where you've got a disc in the side, I've got a plastic drain tap moulded onto the tank - very useful for flushing the tank and needed at the end of the season to drain the tank. I suspect you used to have one!

The disc unit  on the outlet pipe is probably a non return valve. I have one at this location, but different design - it's about an inch long and only about 3/4" in diameter. There is no filter in my system. From the valve the pipe goes directly to an electric pump under the back seat and thence to the sink. There is a footswitch.

There should be wiring from the tank for the water level gauge. I have one as part of the ZIG control panel. It works well. The supply for the pump comes from the Zig panel.

My tank hadn't been used for years either. I only had to replace the fill pipe which was peppered with holes from road chippings! I did a lot of flushing before I used it. Otherwise all worked. Oh, and there is an overfill valve at the top of the tank.

If you go into Wiki, section 16.2 you'll find a Holdsworth Villa wiring diagram.

When I fill the tank, I always add a couple of capfuls of Aquasol to keep the bugs at bay.

Hope this helps.
Pete

That's a great help Pete, thanks SO much for taking the time to explain. That puts things into perspective for me where all this is concerned. Seems like I'm missing parts then. I wonder whether it's still possible to source the plastic drain tap you have on your Villa Failing that, do you think if I release the jubilee clip to the smaller diameter hose (for the water pump, right?) that I could just flush the system through with a hosepipe that way instead perhaps? I have an Auto-Sparky coming to look at my electrics later on in the week. As part of the list of to-do jobs, he's gonna hook up the water pump for me (which is currently disconnected below te back seat). It would probably make sense for me to try and flush the tank through first. (The previous owner informed me that, when it 'worked', the water was brown!)

I would get a new tap installed. Something like this one.
https://www.amazon.co.uk/BSP-Plastic-Ba ... B0051OCHTW 
It has quite a large bore which makes it ideal for flushing the tank and also for draining down at the end of the season. It would probably have to be moulded onto the tank, as you'll have no access to the inside of the tank. You'll need to find a  fibreglass guy to do it - perhaps at your local body shop. I never saw any brown water come through mine!
Cheers!
Pete