Water pump keeps cutting in momentarily

[william4]

The water pumps cuts in momentarily on our 2011 Tracker. I have ckecked all accessible joints for leaks and the system seems ok. Drained some water from hot water drain and reclosed tap. Any advice as to further investigation which I could carry out would be most welcome. I note from one article that it could be the microswitch on the pump,a Shurflo 2095-204-112,but I cannot understand how this coulld cause the problem. Any advice would be appreciated.

[paulmold]

Unless you have taps with micro switches, it is caused by a drop in pressure, either by a dripping tap, a leaking joint or the cooling down of the hot tank which contracts the volume of water. If you leave the MH unattended, switch pump off and same at night so as not to disturb you. Many of us suffer this.

[david lloyd]

Yes we have had this on pressurised systems and could find no leaks so concluded it was the hot water boiler cooling leaving a slight drop in pressure.

 

David

[EJB]

Check the drains underneath the vehicle to ensure there are no drips....particularly the hot water drain and the hot water pressure valve pipe,

[Charles]

There will be a non return valve on the pump outlet, it will have a speck of something in it, and water will be leaking back through the pump... probably. Beer pumps used to do it when I worked on them years ago, common problem.

[Robbo]

Check the plastic filter bowl on the inlet to the pump.

 

Unscrew the bowl and inspect for cracks. Water left in the filter can freeze and cause a crack. Also, check the condition of the rubber O ring. If all OK reassemble and lubricate the O ring with silicone grease.

 

If you have flexible water hose between pump and taps, check the plastic T connectors at joints. These can develop hairline cracks and emit a fine spray of water. Check with the system under pressure.

[maggyd]

Its not worth worrying about ! it has been happening to us in all the vans we have had its just pressuring up.Thats 4 caravans and 2 motorhomes.

[flicka]

If you have heated the Water, then turned that off, the water will cool down & contract. Leaving the pump on senses the slight pressure drop & starts up it top it. Consequently only a quick blip & stops again. The pump will continue doing so until the water is cold & therefore no further contraction.

 

[Derek Uzzell]

William4

 

As has been advised above, if there’s no evidence of water leakage anywhere and the cutting-in of the pump is occurring after water has been heated, it’s likely that this is normal behaviour. If the cutting-in is happening at regular intervals irrespective of whether water-heating has taken place, you MAY be able to address this by adjustng the pump’s pressure-switch via the screw in the centre of the pump’s ‘head’. The screw is arrowed in FIG 2 of the SHURflo document shown here:

 

http://www.holdsworth.vwt4camper.info/SHURfloWaterPumpInstallationAndOperationManualT4WM.pdf

 

and it’s mentioned here

 

http://www.swift-owners-club.com/support/knocking-pumps.html

 

(My current Rapido’s SHURflo pump cuts in momentarily after water-heating as the pressure in the water system drops, but that’s normal. The SHURflo pump fitted to my first motorhome - a Herald Templar - used to cut in momentarily even when water-heating had not been carried out. In the Herald’s case a tiny crack had developed in the water-boiler’s welding and it took a long time for the leakage of water from this to become obvious. So most of the time there’s nothing to be concerned about, but very occasionally there’s a genuine problem.)