swimming pool pump

[madrid]

was called to a job today where one of the pumps for a pool was not working.There was another pump operating the skimmer and cleaning equipment so i take it this one was working in conjunction with the gas boiler to heat the pool.Firstly the old elcb was not tripping when the test button was pushed and the 2.5 butyl feeding the pump was disintegrating.The pump was fed from a dol starter that had no on /off switch and when i took the cover off the device on the right hand side of the contactor had tripped out and had a reset switch at the bottom.could anyone enlighten me as to what this is and I would appreciate if anyone out there could explain the basic set up for domestic pools.there was also a sand filter.I have never had any experience with pools and associated equipment and was going to have a really good look to familiarise myself but the home owner was looking over my shoulder the whole time .

 

[truckster]

I'm gussing the reset switch is the motor overload protection unit which is mounted onto the bottom of the contactor The contactor is probably switched by a T/C and interlocked with the boiler.. BTW if you have a voltage operated elcb it should be replaced with an RCD.

 

[johnboy6083]

a sand filter is basically a filter filled with sand (funney eh?). the water is pushed downwards through the sand, and comes out the other end with less particles in it. chemicals are then added, and it flows to the pool, sometimes through a UV filter and/or an ozonator. after a preset time, or manualy, a multiport valve is used to change the direction of the water, so that it flows backwards through the filter, to waste. this is called a backwash. it removes all of the solids that collect during normal use. the mulitport valve then changes to rinse, which then runs the water down again, but still to waste. this ensures that no particles enter the pool. you then change it back to filter and its good again.

the thing that popped out sounds to me like the thermal overload. this should be resetable, but im not used to older ones, as ive only really worked on newer gear.

if the system is single phase, then often the capacitor in the pumps can fail. these are easily changed, if the windings test out ok.

the rubber cable (ho7 or ho5 usually) can deteriorate over time, if in constant contact with chemicals such as chlorine or bromine. agian these are the only 2 that i have experience of, but otrher chemicals probably damage the cables too.

have you tested the ELCB, with an RCD tester? if it fails, then replace with newer one.

 

[madrid]

The thermal overload is at the bottom of the contactor and had not tripped.This device was similar to a circuit breaker and was at the right hand side of the contactor\the first thing I did was tell him the elcb had to go and have already organised to replace it.I am guessing that when he started all the pool equipment for the first time there may not have been any water in the pump and this has tripped.

 

[johnboy6083]

has the pump got a non return valve on the suction line? this can cure the pump running dry. also check all of the unions, to ensure that there is no leaks, as this can also cause loss of suction

 

[madrid]

Not particularly familiar with pumps but there was certainly no water leaks cant be sure about air leaks.This was a really old set up.25/30 years old easy.I take its working now as I reset it and he hasn't been back on the phone.I was aware a sand filter had sand in it ,just thought they were obsolete now.also didn't see any container or vessels with chemicals .