Lee San & Shurflo Water Pump woes

[wonkywinch]

I bought a Shurflo Aqua King pump from Lee Sanitation last August to replace the noisy Jabsco one and everything was fine for 5 months then the pump stopped working. I traced it to a faulty pressure microswitch that measured 500 ohms when closed.

The internet has reports of these switches failing and I took the precaution to separate it from the default of switching the motor to using the microswitch to a relay to then power the motor. Still the switch failed.

I spoke to Lee San who said send it back for testing and I explained I was going on holiday for two weeks so they had plenty of time to investigate and send a replacement. The engineer promised to look at it as soon as it arrived so I posted it off and went on holiday. A few days ago, I emailed them with a "how goes it". No reply. Got back from my trip and called them yesterday lunchtime, spoke to same guy who said he'd been busy and promised to look at it and call me back within 30 mins. I called at 4.45pm only to hear a voicemail that said they closed at 2pm on Fridays.

I think this is appalling service and I'm minded to do a chargeback on my credit card and buy a replacement pump elsewhere. What do you think? Am I suffering post holiday blues or is this level of service unacceptable. I hate broken promises.

 

[Boater Sam]

Poor service has always been an issue and Leesan is not owned by the same folk anymore so service has got worse.
Reject your purchase as you have given the retailer ample time to replace the pump. Chargeback on your credit card is the easy way but a phone call to Leesan telling them that it is what you intend to do may result in a speedy replacement.
The microswitches are poor, I have seen several fail.

 

[Dockhead]

These are inherently unreliable without a flyback diode. That kind of pump is an inductive load which will give a big back-EMF spike when switched off, and those microswitches have tiny contacts which burn up pretty quickly. The relay is a good idea but the spike can burn those, too. I bet the relay instruction sheet requires a flyback diode for inductive loads. I'd use a TVS diode.

OR, the gold standard solution to this problem is to not use the built-in pressure switch at all, but use a separate Square D or similar adjustable pressure switch, the kind used for wells. These are extremely robust, and you can adjust both cut-in and cut-out pressures. I have one of these but haven't gotten around to installing it yet.

Meanwhile, I have TVS or 1N4007 diodes on all my pumps. Wired across the pump terminals, cathode to + and anode to -. If you use an electromechanical relay rather than a MOSFET, you want a diode across the coil terminals as well.

 

[paulbrown22]

I just removed a 26 year old Aqua King Junior on my Saga 26 HT which was working perfectly well, including pressure switch, but was leaking like a sieve!

I replaced it with a brand new Aqua King, and was hoping to get another 26 years...

I kept the old one though and will hopefully rebuild/reseal it as a spare in case parts quality has come right down!

 

[Boater Sam]

These are inherently unreliable without a flyback diode. That kind of pump is an inductive load which will give a big back-EMF spike when switched off, and those microswitches have tiny contacts which burn up pretty quickly. The relay is a good idea but the spike can burn those, too. I bet the relay instruction sheet requires a flyback diode for inductive loads. I'd use a TVS diode.

OR, the gold standard solution to this problem is to not use the built-in pressure switch at all, but use a separate Square D or similar adjustable pressure switch, the kind used for wells. These are extremely robust, and you can adjust both cut-in and cut-out pressures. I have one of these but haven't gotten around to installing it yet.

Meanwhile, I have TVS or 1N4007 diodes on all my pumps. Wired across the pump terminals, cathode to + and anode to -. If you use an electromechanical relay rather than a MOSFET, you want a diode across the coil terminals as well.

Agreed, these microswitches may have a 10 or15 Amp AC rating but on DC they are at the limit I find.
Another vote for a Square D switch, mine has worked for 24 years but then so has the American Par Max belt driven pump!

 

[wonkywinch]

I modified the Shurflo during install to switch a 40A relay so the microswitch was never subjected to high current. I've bought new relays with diodes built in across their own coil (and thus protect the microswitch against back emf) but I'll also add a diode to protect the relay contacts from the main Shurflo motor back emf.

 

[wonkywinch]

Rang Lee San this morning. Explained they'd had the pump for a few weeks now and I'd like a new replacement. It's being despatched today so I can refit, complete with relay, diodes and snubber to protect the microswitch.

 

[Boater Sam]

Sometimes the polite direct approach can achieve the result you want in the least time. Well done.