Electrical 12V Water Pump Installation

[rjstokes]

Hi all,

I've looked at most of the threads and think I have got this right. Just wanted to put it up before I buy all the bits and make sure!

The Expanda has a pump tap and no hot water (for now). I'm adding a Shurflo pump (revolution?) with the aim of getting pump water when free camping to the tap on the drawbar and the mixer tap inside (on the hot side). I'm thinking the pump will go under the dinnete but did think about putting it underneath with and aluminium cover too?

From what I can tell the pump lines from the tank are 12mm silicone and use John Guest fittings and the mains line is 12 mm plastic also using John Guest except the mixer tap which has some mystery adapters!

If anyone can see something I'm missing from the picture - please let me know!

Cheers!

 

[macca]

Hi all,

I've looked at most of the threads and think I have got this right. Just wanted to put it up before I buy all the bits and make sure!

The Expanda has a pump tap and no hot water (for now). I'm adding a Shurflo pump (revolution?) with the aim of getting pump water when free camping to the tap on the drawbar and the mixer tap inside (on the hot side). I'm thinking the pump will go under the dinnete but did think about putting it underneath with and aluminium cover too?

From what I can tell the pump lines from the tank are 12mm silicone and use John Guest fittings and the mains line is 12 mm plastic also using John Guest except the mixer tap which has some mystery adapters!

If anyone can see something I'm missing from the picture - please let me know!

Cheers!

The mystery adaptor is probably just a weird tee piece, because you have no hot water but the mixer tap has hot and cold, its just a way of joining everything up so there are no leaks. I am a plumber and to be honest have not had a real good look as to what they have done with the pump on my van, but it is a mess of fittings. I will have a look today.
I can say, the pump is inside and it is noisy. I just got rid of the pump tap on the sink and put a filtered tap in and that is connected to mains water. The whole filtered tap kit was $100 (Shurflo brand) which I bought from a local caravan gear shop "Carac" which I thought was a bargain and those pump taps always leak. My plan is to get rid of as much clear silicone pipe as I can, well its not too clear anyway!

 

[boots33]

hey @rjstokes

here is the way i did mine. As you can see I fitted a second outside tap so I can use tank or mains pressure as i choose. At present I have the non return on the outlet side of the pump but find that when the pump is on i do get one or two drops of water coming out of the pump tap now and then. It must get a small pulse from the pump I guess. So I would like to move the non return to where it is shown in the drawing to stop this. I would also advise to get a good quality non return from a plumbing supplier as i had nothing but trouble with the ones supplied by the caravan shops. Nothing worse than a pump that cycles on and off in the middle of the night. There is also a non return mounted up near the pump tap that i have not shown on the diagram. I got all my plumbing bits from Caravans Plus and they have a good tutorial if you have not used the push on fittings before.

@macca do you see any problems in putting the non return on the inlet side of the pump. The main reason i put it on the outlet side is i was not sure whether the mixer tap would allow mains pressure back to the pump if it was in the middle position. Ie mixing the hot and cold at the same time. I guess it should be ok as long as the tap is flowing freely.

 

[macca]

Cant see a problem @boots33 and it should stop water feeding back and making the pump pulse. When you mix two water connections to a mixer tap there is always potential of a mix of both if the tap is in the middle (that's what they do) but that would only be outlet water not between hot and cold connections internally.

 

[boots33]

Thanks Macca

 

[rjstokes]

Thanks guys for the tips, I reckon I might still run with the combined tap idea but will put the non return valve where you pictured it. Presumably you can get decent valves that suit 15mm John guest at plumbtec or similar.

Still not to sure on whether to put the pump inside under the dinette seat or outside under the van, behind the tank under a shroud...

Wish me luck!

 

[boots33]

I'm not 100% sure but I don't think there is any form of stop valve on the mains pressure in line. If you Tee into the mains external tap with your 12v pump line it may free flow back out the mains inlet if you don't have mains connected.

I ended up mounting my pump under the van as it was easier to do , reduced the noise from the pump inside the van and didn't cost me any space inside. The only concerns would be if you did a lot of water crossings and to give the pump protection from stones etc coming up from the road.

 

[rjstokes]

Thanks for that boots33! I'd say your dead right. Looks like I'll need another one way valve or another tap after all. Any recommendations on plumbing places South of the river in Perth that sell John guest fittings and pipe etc.

 

[boots33]

I reckon I might still run with the combined tap idea but will put the non return valve where you pictured it.

just looking at your original diagram and you will need to leave the non return where it is now if you are connecting to the mains. otherwise you will have mains pressure at both positions on you mixer tap and mains pressure at the 12v pump as well... not sure that would be a good idea.
it is handy to have the choice of tank or mains as we have been to some places where the local water is not great.

I think you will find it simpler to fit another external tap and keep the two systems separate. Whichever way you go hope it all turns out ok.

 

[Vaughan Reeve]

Hi all.
I am planning my pump install as well.
I have a 17.56-1 OB with no hot water.
I have attached a plumbing diagram, current pipework in black, and the additions in red.
I am told the shurflo pumps have a non-return in them as well.
Can someone please critique my plan?

 

[boots33]

I would think you might need to at least have another non return valve to prevent mains pressure getting back to the 12v pump. I know most of these pumps have a non return built in but i think that is there more to stop the pump loosing it's prime and sometimes they do a rather questionable job of that too. it may not stand up to the mains pressure which I'm led to believe can be quite high in some places.

At the very least i would shoot an email off to the pump manufacturer and ask them first just to be sure.

 

[macca]

If you are going to run a pump do you need a pump tap. I recently got rid of mine and just put in a filtered water tap hooking that up to the mains water. I think another non return valve like in boots' earlier drawing would be good. Those pump taps leak all the time and I am not keen on drinking water out of a pipe that started off as clear but turned green after a while!

 

[Vaughan Reeve]

Do you think that this would be a better setup?

 

[Bmhdg76]

Do you think that this would be a better setup?
View attachment 22728

I would move the non return valve on the pump line to be on the pump outlet line.

Brendan

 

[rjstokes]

Thanks guys for the input. Big effort taking time out to look at someone schematics! Here's my final take (I think!). I've applied in earnest the KISS principal. I'm thinking of replacing the <rather useless> pump tap with a spare filter type tap from our kitchen reno, and keeping the two systems completely separate. That way there's no non return valves to fail, minimal connections to leak but we still get pump water to the sink and to an external tap.

The only problem I can see is if the battery power fails (in which case it would be dark and not much fun anyway) or if the pump fails - we'd have to drain the tank into a bucket - or refit the pump tap I'll keep in the toolbox. Something like this :

 

[boots33]

Yep that will work as long as the non return in the pump is up to the task. If you find the pump cycles on now and then you can easily fit a good non return on the inlet line of the pump later.

 

[rjstokes]

Hi Boots. It's been a while and the pumps been working great. Except recently it's been cycling on and off with the taps closed. I.e. You turn the tap off and the pump will still run intermittently. Was wondering if that was what you referring to with the one way valve on the inlet side of the pump (I'm a bit confused about that!). Otherwise thought an accumulator might help?

 

[boots33]

There are a few things that can cause the pump to cycle without the tap turned on.

1 water leak on the pressure side of you system between the pump and the taps..... This could be from a leaking tap or joiner or even from a stone chip to one of your lines. It will only need a very small leak to cause problems. You will have to do a visual inspection of your lines from the pump to the taps and check for any signs of moisture.

2 Faulty pump non return valve (yes this is what I was referring to in my post above)..... most of these small pumps don't have a dedicated non return valve, they just rely on the flexible diaphragm that is used in the pumping process to stop the reverse flow . Sometimes these do not seal properly and allow water from the pressure side to be gradually leaked back to the low pressure tank side of the pump. Eventually the pressure will drop enough to activate the pressure switch and cause a quick cycle on of the pump.

To fix that you will need to fit a good quality non return valve (get it from a plumbing supplier) between the pump and the tank. This will stop the water draining back and stop the cycling.


3 faulty pressure switch. This is very uncommon, most of the time they either work or they don't.

4 Air in your lines... If your pump is sucking air this can also cause intermittent pump cycling.

You will normally notice the water spluttering a bit when you first turn on the tap. You should check your fittings on the tank side of the pump for loose or broken clamps etc.

Any of the above could cause the pump to cycle but number 1 and 2 are probably the most likely culprits. I would check for leaks first and then fit a non return valve if necessary.
An accumulator would certainly prolong the time between pump cycling but likely not stop it all together.

 

[rjstokes]

Wow, thanks so much for your reply. Stunning contrast from the help I just received at the local caravan parts place! I'll go have a look.

Cheers!

 

[boots33]

If you do end up fitting a non return use something like this one . you will have to get tail ends to suit your hose as well. I tried a few from the caravan suppliers and they all failed to fix the problem. have had the brass one in for a few years now and still no problems.