my pump woes

[takeiteasy]

As some may remember I decided to reroute the tank filler pipe so it didn't come through the van floor and replace the 12v pump with a manual one I bought a Fynspray galley pump www.whitworths.com.au/main_itemdetail.asp?cat=133&item=68122&intAbsolutePage=1&LinkedItem=68205&search123=
Upon connecting and priming it I found it wouldn't hold a column of water and couldn't raise a column from tank to sink. I removed it and tried in a bucket and it couldn't cope with any length of pipe above 750mm. So I got another one from the supplier. Thing is the old one worked ok when we tried it in the shop... as did the new one. But now the new one won't work on my tank either. I have tried different diameter hoses, checked for leaks dozens of times, primed it dozens of times. It works after priming, then after 20 mins of so it has lost its prime and will not raise a column of water no matter how hard or long I pump. I am absolutely stumped and more than a little distressed by this mystery. I have moved the filler pipe so it fills from a clip on hose at the front of the van (it has a tap on it). Could this cause a problem? The breather pipe is still short and unencumbered though. Can anyone save my sanity with their pump wisdom?

I have posted similar of caravanner's forum so apologies if you see this twice. cheers, Bill

cheers, Bill

[Geoff & Jude]

hi bill

if you have a look on page 108 of the camec catalogue, you'll find they sell a 1/2" dia in-line "whale check valve" to suit 1/2" inside dia hose.

this will 'help' stop the pump from siphoning back to the tank and keep it primed.

the only problem with them is they need about 1 metre head to maintain the check function.

there is also another "dm plastic check valve" on page 96 that suits 1/2" outside dia tube.

geoff 'n jude

[takeiteasy]

Thanks G&J. The manufacturer assures me it is not necessary but it's a solution I will grab if I can't find any other problem. Wish they had prices on the catalogue.

[Deleted]

hi bill

they're about $15.

conti

[humpyboy]

G'day Bill, before I start I know nothing about pumps and tanks in vans BUT I have been watching this thread and thought I'd throw my 2 bobs worth in, the one thought that jumped into my mind was, or is it possible that you are creating a vacuum in the tank after your first attempt at pumping water? once you stop pumping the air would want to return to the tank thus taking the water with it, just a loose thought running through my empty mind maybe it will stop now that I've posted it ;D ;D ;D ;D

[DC3Td]

And my two cents worth Bill - would not a 12v pump like a fish tank type alleviate air probs? Only say that as i`m going to strike what you`re up against when i install a water tank to the Td. cheers gordon

[takeiteasy]

Humpy, I have investigated that problem as I thought the breather pipe might be blocked. Could have been the problem but wasn't.

DC, that is too complicated. Its adding a component to compensate for a fizable problem (and it must be fixable). After sleeping on it I think there are three problems: the first is the pump stem is tapered to accommodate different hose sizes, thus it is more difficult to get a good seal, the second is the tank stem and pump stem are not matched in size, and thirdly, the tank stem is old, worn, and mis-shapen, thus making it hard to get a seal. I am just going to have to redo everything (again) with new hose and spend a lot of time establishing each seal (not that I haven't already). If that doesn't work I will try a nonreturn valve (shouldn't be necessary). If that doesn't work I will throw the new pump as far as I can and reinstal the 12v system.

[takeiteasy]

I made this video and learned how to put it on youtube (I am a bit chuffed about that). I believe it shows that the nonreturn valve on the pump is faulty. This is the second pump (and second trip to perth.... pffffttt). What do you think? It should not drip like that. Link below:



or

www.youtube.com/watch?v=jK7G50Sso34&feature=youtu.be