# Hymer Water Pump Problem



## finchamfamily

RE: Hymer 644G 2007 model

While prepping the van after winter lay-up the only problem that wasn't there before is a loss of pressure to the kitchen tap. The bathroom tap works fine and the distance from the pump is similar. The kitchen tap and line don't appear to a have blockage as the water flow is consistent, just not under pressure. The micro-switch is activating the pump as I can hear it. The boiler is re-filling OK after just a couple of minutes of splut splut.

I've read that some Hymers have a tandem pump and therefore one-half can work while the other is broken. Is this true? I've removed my pump and it is labelled Tandem (19L 1.4 bar) but there is only one line out so it appears to pump water to both taps and the split must be elsewhere in the system. I will order a new pump from Brownhills as I know they are a handy thing to carry on-board, but my worry is that the problem will still be there after the swap-over and we are off touring over the Easter WE.

Any advice is gratefully received.

Martin


----------



## Bobfiggis

Hi

Is the problem the same with both hot & cold feeds?
What is the effect of having both kitchen & bathroom taps open at the same time? on hot? and on cold?

I presume you were happy that the system was completely drained over winter with taps open etc .


----------



## finchamfamily

Thanks for the suggestions. I haven't noticed any difference in behaviour based on the various combinations of "off/on hot/cold" but I will run through all the permutations again tonight to be sure. Certainly hot and cold water flows from both taps. The pressure on the bathroom tap is almost too high and causes splash-back when wide open. The kitchen tap has consistent low flow, like pouring water slowly from a jug.

This is my first year with a MH so I may have made a newbie error over the winter, but I did drain down, leave taps open etc. The only thing I didn't do was blow thru all the pipes. The van has been kept under cover on my drive (sheltered) and kept reasonably frost-free during harsh cold snaps by way of a mains-powered oil-filled rad in the living area.


----------



## erneboy

Many taps have a nozzle which unscrews, these often have a little gauze in them, this can become clogged. Since the pressure is good at other taps I suspect you have a blockage somewhere. Try the tap, if not there try disconnecting a few pipes and running some water into a bowl and see if the pressure is OK, Alan.


----------



## finchamfamily

Thanks for the extra tips!

I went through every combo of on/off, hot/cold last night and everything works fine, bar the low pressure on the kitchen tap. I did remove and clean the nozzle [good tip] and that slightly improved the flow.

What did puzzle me is that the pump makes a different noise when the second tap is activated, as though it is trying to work harder. This harks back to a previous theory I read on the net that this Hymer pump - called a Tandem - actually has two motors and one side can fail. But there is only one wire to switch it on and one water outlet, so how can the pump know whether there are 1 or 2 taps open? Unless it is clever and senses the extra demand of the 2nd tap which in turn activates the 2nd motor? But then the kitchen tap would work fine if it was the 1st to be activated...hmmnn.

Anyhow, I have a new pump arriving from Brownhills today or tomorrow so I will get a definitive answer to the question and post an update.

Regarding a potential leak or fracture elsewhere in the circuit, I am sceptical as I would expect to have seen evidence of a leak by now. I have pumped two full tanks worth of water thru the system. I haven't removed all the kitchen draws to inspect behind because that is a bit of a pain, but that's the next area for investigation if the new pump doesn't magic the problem away.


----------



## JeanLuc

Can't think of a reason for the problem. I suppose you have checked that both drain cocks in the base of the wardrobe are fully closed?

By the way, I'd be interested to know how much Brownhills charge for the pump; it's available from Marcle Leisure for £29.36.

Philip


----------



## teensvan

Hi.

This may be a daft idea, but if the tap is fed by flexi pipes that could have got squashed somewhere behind a unit or where it passes through a locker.

steve & ann ------- teensvan


----------



## finchamfamily

More good suggestions, thanks guys.

@JeanLuc, yes I did check the drain cocks again (in the garage in my case) because that immediately felt like the kind of newbie error I would make :lol: Unfortunately, the solution was not so simple. Brownhills offer the Hymer unit for £57.34 + VAT or a 3rd party equivalent (Reich?) for £44 + VAT. I went for the 3rd party option because it was in stock and the WE is getting close.

@teensvan, my plan is to try replacing the pump in next 24 hrs (thought handy to have a spare even if not root of this prob) and then start checking the pipework specific to the kitchen tap feed. I think any leak would have shown-up by now but a kink is possible although the van hasn't moved an inch since before winter when everything worked perfectly. Frost damage is a possibility, given the winter we've had, but I do have the benefit of double-floor routing, covered MH, oil-filled rad on frost setting etc. so I'll be disappointed if it's that. But this is my first winter so my hope may be misplaced.

Will report results for future reference.


----------



## JeanLuc

Hope you get everything sorted out. For info., next time you need a pump (they fail periodically) I suggest an independent supplier.

The Hymer pump is a Reich twin-barrelled version, but carries a Hymer logo, otherwise it's identical. Below is the link to Marcle leisure for reference. I know it's poor consolation "to bolt the gate etc.", but their price of £29.36 even after adding carriage is, I suspect, quite a bit less than Brownhills' £51.70 inc VAT.

Philip

Marcle Reich Pump


----------



## coppo

Thanks for the tip about the pump Philip and the cheapest place to get, i shall be ordering one of those shortly, especially as we are now keeping this MH.

Paul.


----------



## Bobfiggis

Martin

Before you fit the new pump you may like to read this thread.

http://www.motorhomefacts.com/ftoptitle-10852-hymer-water-pump.html

I changed my pump and did the "bucket test". I did find that wiring the pump the apparently "wrong" way (blue to brown & vv) made a difference to its performance !??

Certainly from other posts on MHF it appears that you cannot assume Hymer wiring will follow the Blue = -ve; Brown = +ve convention we have on mains in the UK.

Hope the new pump sorts it.


----------



## pieterv

I had a similar problem, but in reverse: enough pressure in the kitchen but not enough in the bathroom. Like you I assumed a partial blockage somewhere leading to the lower pressure pump.

Could not find any blockage, so replaced the pump, which made no difference.

It turned out that the proble was not the pump nor a blockage, but a crack in the small plastic manifold that the pump connects to. A considerable part of the pump's output flowed straight back into the tank. Replacing this solved the problem.

(Although I still don't understand why kitchen flowed fine, and bathroom didn't!)

So, when you replace the pump you might want to check for that. Just open one of your taps, and slightly lift the lid of the water tank and look for any spillage/leaks.


----------



## Hymie

*Pumps & Taps*

For future reference, Hymers accessory co known as Movera also offer the pump (Eu39.95 so a little dearer).

They also now have in their 2010 catalogue the later type taps for the up to 2008 models.

Much cheaper than buying them via the Hymer parts channel - yet still supplied by them!

I have always found Hymer UK very helpful in ordering anything from the Movera catalogue - just give them the relevant part number.

You can see the catalogue (500 pages) online here: www.movera.com

- but note that there are more products available on the German text version.

Happy Travels


----------



## Bob45

Thanks for the info on the water pump, JeanLuc.
I have ordered one from Marcle to carry with us as a necessary spare.
Bob


----------



## SidT

I have just bought a pump from Peter Hambilton at Hymerdirect.com I don't think it was the same pump but was £35 inc VAT. might be worth making a note of their number...01772 315078. they are usually cheaper than Brownhills.

Cheers Sid


----------



## kayden

can anyone tell me how to fill the washer bottles for screen on a hymerb544 it is not in the engine


----------



## finchamfamily

New pumped fixed the problem.


----------



## SueandRoger

JeanLuc, Thanks for the details on the pump supplier and I also have now ordered one as a spare.


----------



## BillCreer

I bought a Reich twin pump 19L/min 1.4 bar for £20 on Tuesday.
If you're quick they had about 5 left on the rack at the shop of the former "Barrons" place near Chorley. (now called "Discover")
I resisted the urge to buy them all and sell on eBay.


----------

