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Water pump woes

Tom Richmond

By Tom Richmond
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Tom Richmond Proficient

Tom Richmond

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Hi all.

 

Got up this morning, went to fill kettle, no water from taps! Luckily I managed to collect enough water for a cuppa from a few half empty drinking bottles, because the subsequent diagnosis and fix would not have been any fun before having had my morning tea.

 

Turned out a crimp inside the microswitch enclosure on the bottom of the pump had pulled off the end of it's wire. Bingo! Easy enough to fix once I'd found it...

 

So, I reconnected everything (and fixed the sliding door used to get to the cupboard where the pump lives), only to find that the pump is now behaving very strangely indeed...

 

Basically it is not cutting in. So, turn tap on, water flows, water slows as accumulator slowly empties, water stops flowing... Wait... Wait some more... Then pump cuts in, water flows, accumulator fills and (assuming you turn tap off) pump stops. Next time you use tap, repeat above. The wait is anywhere between ten seconds and a minute (not joking - walk away with open taps, do something else, come back when the water starts flowing again!

 

Now, I had to dismantle the switch assembly, including the little rubber pressure membrane, etc (pump is a shureflo), and I did clean as I went, but what did I do to cause this?

 

I adjusted the accumulator in an attempt to fix it, but it made no difference, either + or -. The pump has a single screw adjustment marked 'cut out pressure' which controls the spring against which the rubber membrane pushes in the switch assembly, however cut out is fine. Annoyingly pump is mounted close to floor so that this screw cannot be adjusted without removing pump completely.

 

Thanks in advance for your collective wisdom.

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Tom Richmond Proficient

Tom Richmond

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Did you take the switch off to fix it?

Yes. Microswitch and offending crimp housed in plastic case on bottom of pump. Four screws hold case on to main pump, and two more hold switch part of case together, all six came out to open up and expose broken crimp. This caused spring, rubber membrane, and lever which triggers Microswitch to all tumble out, but all seemed to locate and go back together easily enough...

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WotEver Veteran II

WotEverDonate to Canal World

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I feel better about the idea of doing it again than I do about the idea of standing in the shower waiting for pump to kick in...

 

But what am I trying to change?

Either you fix the pressure switch that you (presumably?) put back together incorrectly or... you buy a Square D remote pressure switch http://m.ebay.co.uk/itm/152252422420?_mwBanner=1 and use that to control the pump. They come highly recommended.

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Iain_S Influencer

Iain_S

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There is usually a plastic bit with a small hole in it on the water side of the pressure switch rubber membrane. The hole is REALLY small and easily blocked.

A near complete blockage would cause your symptoms.

The hole can be opened out to 4mm or so without apparent effect on pump operation, and, at that size, is a lot less likely to get blocked in the future.

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IDS Collaborator

IDS

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If you dismantle the switch housing again look for the switch or its actuator lever ( if it has one) being not quite seated correctly. You can also check that the switch is operating reliably electrically if you have a multi-meter. Check the resistance across the terminals when it is in its rest position when operating the switch manually, it should be much less than 1 ohm. These switches do fail when the internal contacts burn and go high resistance. Replacement switches are available from pump supplier (or Ebay/Maplins ... cheaper - make sure to get one with a contact rating of at least 10A )

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cereal tiller Veteran

cereal tillerDonate to Canal World

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Either you fix the pressure switch that you (presumably?) put back together incorrectly or... you buy a Square D remote pressure switch http://m.ebay.co.uk/itm/152252422420?_mwBanner=1 and use that to control the pump. They come highly recommended.

Good idea,have got one of those Remote Switches and have installed a Pressure Gauge adjacent to it

 

Setting up the cut in-cut out pressure becomes easy and accurate

 

CT

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ditchcrawler Veteran II

ditchcrawlerDonate to Canal World

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Good idea,have got one of those Remote Switches and have installed a Pressure Gauge adjacent to it

 

Setting up the cut in-cut out pressure becomes easy and accurate

 

CT

How far from the pump is it. I had lots of problems with it bouncing with the pump pulses

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WotEver Veteran II

WotEverDonate to Canal World

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Thanks all.

 

Dismantled, cleaned little hole (and one way valve on pump side of it) and it all now works like a dream. I did not drill the hole any wider, as the one way valve has a piece which locates into it, and I was worried I would do more hard than good...

Great news. :)

 

Might still be worth buying a remote switch to keep in the spares box for when the switch finally dies.

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RD1 Contributor

RD1

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I replaced a micro switch on a whale pump, and it failed again a few weeks later.

 

There are switches and there are switches, most will say 10 amps at 240 v ac so you think... should be ok for 3-5 amps dc

Wrong, they can handle a couple of amps at dc, unless they give the rating on the switch.

 

You need to hunt around for a heavy duty microswitch designed for say 10 amps dc. Good luck !! Most ebay switches are from the far east, and are optimistically rated, from my experience with them.

 

The best approach is to ignore the pump micro switch and go for the external type as mentioned I think they are £20-£25 but they do have an adjustment knob, which you can place in a suitable accessible position.

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cereal tiller Veteran

cereal tillerDonate to Canal World

Posted
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I replaced a micro switch on a whale pump, and it failed again a few weeks later.

 

There are switches and there are switches, most will say 10 amps at 240 v ac so you think... should be ok for 3-5 amps dc

Wrong, they can handle a couple of amps at dc, unless they give the rating on the switch.

 

You need to hunt around for a heavy duty microswitch designed for say 10 amps dc. Good luck !! Most ebay switches are from the far east, and are optimistically rated, from my experience with them.

 

The best approach is to ignore the pump micro switch and go for the external type as mentioned I think they are £20-£25 but they do have an adjustment knob, which you can place in a suitable accessible position.

Have used a Relay to switch the Pump on,reduces the wear on the External switch

 

CT

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Flyboy Experienced

Flyboy

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My recommendation to anyone that has has a Shurflo or similar pump that uses a microswitch is to add a car type relay to relieve the heavy current from it. Although the Square D pressure switch is excellent, a car relay is a much cheaper option & easier to fit.

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WotEver Veteran II

WotEverDonate to Canal World

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Posted (edited)

There are switches and there are switches, most will say 10 amps at 240 v ac so you think... should be ok for 3-5 amps dc

Not specifically to do with this thread but the above misconception is both common and false. If forced to give a ball-park 12V DC rating for a 240V AC switch then the most I would give it is 10% - so a 10A AC switch 'might' be okay at around 1A DC. However the only way to know for sure is to buy a DC rated switch and use it well within its rated maximum. You're unlikely to find one of those cheap on eBay; RS or Farnell are much more likely suppliers.

 

edited for spillung

My recommendation to anyone that has has a Shurflo or similar pump that uses a microswitch is to add a car type relay to relieve the heavy current from it. Although the Square D pressure switch is excellent, a car relay is a much cheaper option & easier to fit.

 

And if the little Durite relay were to fail then it's a 5 second job to unplug it and plug in a replacement.

Edited by WotEver
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Tom Richmond Proficient

Tom Richmond

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Revisiting this post after a long while with a progress report.

 

My replacement microswitch failed after a few months. I fitted a Square D pressure switch. It is excellent! I would highly recommend one to anyone struggling with the switches on their pumps.

 

One word of warning: The pump has a 1/4"BSP female thread to connect to the plumbing. I struggled to find a fitting to go from 15mm pipe to 1/4" BSP. Screwfix, toolstation, wickes, B&Q and plumbase all failed me before I found something in BSS drainage and plumbing. Suggest anyone sourcing a new pressure switch gets the appropriate fitting at the same time!

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smileypete Veteran II

smileypete

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Thanks for that, helps any one who's considering getting one.

 

Am surprised you drew a blank at Screwfix and Toolstation as they both do a 1/4 to 1/2 inch BSP threaded bush for about £1 which will get most of the way there.

 

Maybe the counter staff have limited knowledge of plumbing so a specialised merchants would be a better bet as you found.

 

Part of the knack of plumbing is being able to make fairly unusual connections from much more common bits. :-)

Edited by smileypete
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