shurflo waterpump (1 Viewer)

[marc]

Hi everyone looking for a bit of advise.Had my van for a couple of weeks now ,been out acouple of nights ,so far everything gone well except for the waterpump.Drained truma and fresh watertanks, refilled truma opening taps to get air out, After turning tap on i can hear pump pressurising the system after say 15 20 seconds pressurising stops but the pump carries rumbling on until i switch it off at the panel, dont think its doing a right lot just making a din.I've been reading through older posts trying to find info, can anyone offer any suggestions, cheers newbie Marc.

 

[old-mo]

Long shot but try opening and closing a few times each tap individually,, sounds like it could be a sticky micro switch..

 

[pappajohn]

the pump wont stop UNTIL it is pressurised and it sounds as though yours isn't pressurising.

if the taps have micro switches then it wont pressurise at all...it just pushes water through when a taps opened.

could be a hidden leak or an air lock.

have you opened the hot and cold SHOWER TAPS as well as ALL the others and if your toilet flush runs off the fresh tank (no flush water tank) try flushing that a while to get any air out of the pipes

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[marc]

Thanks for replyies yes i've had a go with flush and shower taps can't find any leek inside or outside suppose it can only be either damaged pump, leek somewere, or air block.I spoke with dealer over the phone thet seem to think its the pump.Dont know out about micro switches Mo, anyroad i'm off to bed, sleep on it i think. cheers marc.

 

[pappajohn]

if nthe pump had any residual water in it and it froze it could have damaged / split the diaphram....that would cause it to run continuously and maybe still push some water through the taps.

you can buy repair kits for shurflo pumps.
cheaper than a new £80 pump. :thumb:

 

[Robinhood]

Thanks for replyies yes i've had a go with flush and shower taps can't find any leek inside or outside suppose it can only be either damaged pump, leek somewere, or air block.I spoke with dealer over the phone thet seem to think its the pump.Dont know out about micro switches Mo, anyroad i'm off to bed, sleep on it i think. cheers marc.

The 'van water system may either be operated by a microswitch system (where switch contacts on each tap are made when it is turned on, and they activate the pump), or by a pressure-switched system, where a microswitch located outside a rubber diaphragm on the end of the pump is triggered on/off as the diaphragm moves either way under pressure, or release of that pressure. The tap microswitch system is more common on caravans than motorhomes, and the symptoms you are experiencing are certainly more aligned with the pump microswitch system (though all things are possible).

It isn't uncommon for the diaphragm to 'harden' during a lay-up period, and this will change the switching pressure/point, often to the extent that the pump will either not switch on or off.

I've had the same issues as yourself at the start of a season, and have managed to correct it by removing and dismantling the diaphragm/switch unit (drain down required), and flexing the diaphragm before reassembling. It's a relatively easy job if you've got clear access to the pump, but you need to be confident in your DIY capabilities. The switching unit is usually a separate, removable unit at the end of the pump, and is obvious because of the wiring going into it.

HOWEVER, if it is removed and flexed (and you can also check that the diaphragm isn't damaged) it will probably need the microswitch switching point adjusting on re-assembly. This is usually achieved by turning a small screw on the end of the microswitch unit, and by trial and error finding the point at which it switches off when pressurised, and on when a tap is opened. SMALL adjustments only in each direction until this sweet-spot is found.

SO, if you can find the screw adjuster (probably right on the end on a Shurflo), BEFORE any dismantling it might be worth seeing if this can be turned to reduce the shut-off pressure and shut the pump off, whilst still ensuring it still restarts when a tap opens. It is likely that anti-clockwise will make the pump shut-off earlier. (Also, be aware that if you use this method, continued use of the water sytem over time may 'flex' the diaphragm, and once it is bedded-in the switching point may need to be re-adjusted slightly).

(I'm also assuming that you are sure that you've fully filled and pressurised the HOT water circuit, as cold water will flow on my 'van whilst it is still filling the hot side for some minutes before it comes up to pressure).

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[JJ]

A long shot but... sometimes if your voltage is low a pressure system pump is more reluctant to switch off...

JJ

 

[marc]

Thanks for the good advice guys,i've had a tinker with the screw on top of the pump and found the sweet spot pump now pressurises then stops. Ive run quite abit of water through the hot and cold system trying to push the air out but i cant get a steady flow through seems like there's air trapped how long would it normally take to get air out of the system or is that like asking how longs a piece of string, Thanks Marc.

 

[Robinhood]

....how long is a piece of string?

Cold side usually pressures up fairly quickly, with steady stream. Hot, which will be a more convoluted run, and also need two gallons or so to be pumped into the boiler if its been drained down, can take significantly longer.

I normally get a good amount of water in the tank, close all taps, and let the pump run until it cuts out. Then open a cold tap until there's a steady stream (pump should run). close it and let system pressurise until it stops. Then open hot tap and let it run until a steady stream (again, the pump will run). This takes some time (can be minutes), and the tap may 'spit' quite a bit. Closing the tap from time to time until it is under enough pressure to turn the pump off, and then reopening and repeating, can restrict the 'spitting'.

Air locks are possible, but not really that common, and if your pump is now switching correcly, I think you probably need just to persevere.

Good luck.

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[marc]

Thanks for that I'll have another crack at it tonight, just cant get a constant flow, hope its an air lock not sure how to check for air leek cant find any water about, was thinking about changing pump 40 odd quidish as last resort, I'll have ago when i'm home from work, tthought about taking off to the lakes this weekend anyroad thanks for advice Marc.