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In a whirl


dawki

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Hi all just getting van ready for a trip away this weekend

I have filled with water as usual the water has come through to all taps but the Shurflo pump keeps whirling away it gets very faint after a few minutes but won’t stop completely

Have checked filter it’s the original pump 14 years old now so new pump needed???pump is 2095-204-412

 

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AFAIR, Shurflo pumps are pressure-switched by an integral, diaphragm-controlled unit on the end.

 

If there is no leak (as you say) then it may be that this switch has gone out of adjustment. It is not uncommon after non-use, as the diaphragm may lose some flexibility.

 

The symptoms may also be consistent with this, as the switch (off) may not work, the pump continues to run against increasing pressure, slows down, and thus becomes quieter.

 

There should be an adjustment screw on the pump which adjusts the switching point of the integral pressure-switch.

 

The switch is operated by a diaphragm, one side of which is the (pressurised) water, and the other is the plunger for the switch.

 

As the pressure rises (e.g. when the taps are closed) , the plunger is pushed and the pump is switched off. When the taps are opened, there is a drop in pressure, the plunger is released and the pump switches on.

 

If the pump does not respond quickly when a tap is opened, then there is certainly a possibility that the screw needs adjusting (likewise, if the pump does not turn off quickly, but runs on).

 

There is a sweet-spot on the adjustment such that a drop in pressure immediately switches the pump on, and a rise in pressure rapidly turns the pump off. Over-adjustment is likely to cause the reverse problem to that you are seeking to resolve, so a search for a reasonable central point is important.

 

It may be that you need to make that adjustment. It will be via an Allen or crosshead screw on the end of the switch (which is where the wires meet the pump).

 

The pump instructions should describe the method, and the required direction to turn the screw (usually only in small increments).

 

If you haven't got the instructions, the web should be your friend (or post the pump model). I suspect most similar Shurflo models will be the same.

 

Be aware that, if this resolves the issue, you may well have to re-adjust later as things become more flexible with use.

 

This all assumes that the water system is (only) pressure switched, which most Shurflo installations are. If the pump is energised by microswitched taps (or alternatively, by a hybrid microswitch/pressure system as I had on a Hobby), then there could be issues with microswitches at the taps.

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The 2095-204-412 is the 7-litre-per-minute flow-rate/20psi pressure pump that’s probably the SHURflo Trail King model most commonly fittred to motorhomes - my 1996-built Herald, 2005 Hobby and 2015 Rapido all used that pump.

 

(Dawki’s motorhome is an Auto-Trail Cheyenne 696G - presumably a 2006/2007 version - so won’t have the unusual micro-switch arrangement Hobby chose when a SHURflo pump was used on their Ford Transit-based motorhomes.)

 

The informationon on this elderly Installation/Operation Manual document is still valid

 

http://autohomes.vwt4camper.info/SHURfloWaterPumpInstallationAndOperationManualT4WM.pdf

 

and the trouble-shooting section includes the following checks that should be made if the pump runs continuously

 

PUMP WILL NOT SHUT-OFF/RUNS WHEN TAP IS CLOSED

- Output side (pressure) plumbing for leaks, and inspect for leaky valves or toilet.

- For air trapped in outlet side (water heater) or pump head.

- For correct voltage to pump (±10%).

- For loose drive assembly or pump head screws

- Are the valves or internal check valve held open by debris or is rubber swollen

- Pressure switch operation/adjustment incorrect, refer to shut-off adjustment

switch.

 

It is possible to purchase spares for Trail King pumps

 

http://www.groveproducts.co.uk/medias/documents/grove/cata/BIZ1801%20Spares%20Shurflo.pdf

 

but the price of (say) an upper housing & switch’ kit' may be more than 50% of the cost of a brand-new complete pump.

 

If adjusting the pressure-switch (as Robinhood and the SHURflo instructions describe) does not effect a cure, as the pump is now 14 years old replacing it would make sense, rather than dismantling the pump and trying to repair it.

 

SHURfloTrail King pumps are nowadays manufactured in Mexico and this ebay advert (£55.90) for a 2095-204-412 is probably a cheap as any and includes the latest filter and two ‘barbed’ connectors.

 

https://www.ebay.co.uk/itm/171547564513?chn=ps&mkevt=1&mkcid=28

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The installation instructions refer to a Service Bulletin which describes how to adjust the pressure switch, but I can't find a download for that anywhere on the web.

 

Essentially, you're trying to reduce the pressure at which the switch cuts out the pump.

 

Whilst I won't vouch for it, I can find advice that says : "Turn screw clockwise to raise shut-off pressure,

counter-clockwise to lower shutoff pressure", so counter-clockwise seems sensible to try first (but do try the other way if that doesn't work).

 

I wouldn't go much more that a quarter turn at a time (and then slowly and only a few times) with the pump running to see if the adjustment will make a difference (i.e. you find a point where it switches off).

 

It is then a matter of checking that it turns on responsively once a tap is opened. When working properly, there is a "sweet spot" or mid-point where the switch is correctly adjusted to switch both on and off responsively.

 

And, as I've said, don't be at all surprised if you subsequently have to re-adjust a bit, as continued use may increase the flexibility of the diaphragm, changing the switching resistance.

 

(I had a 'van with a Fiamma pump, switched on the same principle, that required adjustment after every lengthy lay-up, and then again once it had settled down)

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The SHURflo Installation and Operations Manual supplied with my 2015 Rapido is in 5 languages, but otherwise mirrors the old manual I gave a link to above. My Rapido’s document has the reference 911-564 REV B and the German-language part of it is here

 

https://www.living-to-go.de/downloads/Frischwasserpumpe.pdf

 

The manuals all include the image attached below that - as you’ve advised - indicates that turning the adjustment screw clockwise should be done if the pump cycles too oftren (or won’t shut off). The procedure is covered in the manual’s “Switch Shut-Off” section.

 

The SHURflo pumps used in my motorhomes over the last 23 years never needed this type of adjustment.

shurflo.png.c58bfb97ece2cde69374475520fde0c3.png

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Hi All I’ve been out to have a look at the pump

I adjusted as suggested but no matter which way and how much I turned the screw it didn’t help

I then removed pump and checked to see if it was clean inside

It was clean

replaced it and tried adjusting again but no change

New pump next?

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Guest pelmetman
dawki - 2021-04-15 7:47 PM

 

Hi All I’ve been out to have a look at the pump

I adjusted as suggested but no matter which way and how much I turned the screw it didn’t help

I then removed pump and checked to see if it was clean inside

It was clean

replaced it and tried adjusting again but no change

New pump next?

I'm on my third pump ;-) .....

 

It's not a big issue to change them so long as you get the right pump :D .......

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dawki - 2021-04-15 7:47 PM

 

...New pump next?

A ‘check valve kit’ is available for about £10 (example advert here)

 

https://www.williamsonpumps.com/94-237-00-category--a-1062-p.asp

 

but there’s no certainty that this would cure your pump’s problem or that you’d end up with the correct 20psi cut-off pressure. An upper-housing kit (that would include the pressure cut-off switch) would cost about £30 - and there’d still be no guarantee of a fix. So a new pump is the logical next step.

 

Presumably you’ve made absolutely sure that all your motorhome’s water system’s drain valves are closed? And that, when the pump is running and the taps are opened, that the water being delivered from the taps has the flow-rate and pressure you’ve been used to? In the latter case, if there were internal damage (say a split diaphragm) that prevented the pump from pumping at full power, that MIGHT cause it to run continuously - but even if that were so, fitting a new pump would be preferable to repairing the old one.

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