Hitachi GX pump cycling on and off

[Negita43]

My Hitachi GX pump keeps cycling on and off. It's about 5 years old and it has to lift water about 12 feet to the house taps/showers. It is fed from a 1000 liter storage tank.

 

If I turn on a tap anywhere in the house then pump starts cycling on and off quite rapidly. However , if I turn on a garden tap - effectively a lift of about 3 feet it switches on it runs fine (no cycling on and off)

 

I'm no expert but as this pump is activated by water pressure when you turn on a tap I suspect I have air in the system somewhere BUT I have bled the pump and left all the taps in the house on for 10 minutes (and cannot see any air bubbles coming through) and I cannot solve this issue.

 

Anyone have any suggestions (apart from buy a new pump!! although it may well come to that).

 

Thanks

[Negita43]

Actually, thinking about this I wonder if I am concentrating on the wrong issue? Is it possible that the air might be on the supply side?

 

[davidkas]

Hi there, a bit late now. Did you get you problem sorted? I have a couple of the Hitachi pumps, I had a problem with water snails getting into the tank. The snails migrated into the pump and prevented the valve from shutting off and this resulted in the kind of cycling problem you had.

if you take the plastic cover of and look for the large 30-40mm plastic cap/plug. Take this of and have a look inside (make sure power off and water isolated) anything inside can cause a problem....