rainwater harvesting

[Richard BraunParticipant]

We installed a rainwater harvesting system in 2011 which uses a Hydroforce submersible pump. We are now on our 5th pump. Each pump has developed a fault within 3 – 6 months which trips the electric circuit. The fault has always been traced to the pump not the underlying electrical system. The company has replaced the pump each time but has not solved the underlying problem. Has anyone experienced similar problems with this type of pump.

[Peter GoldieParticipant]

I had a Hydroforce submersible pump Series 3 pump replaced under guarantee after about 18 months. About 3 years on I have a renewed intermittent tripping problem. It is protected by a 30mA RCD ELCB. I suspect the problem is in the pump.
A few recommendations:
1) Avoid external connection box – always bring the flex indoors. Exterior connections even in an IP66 box risk condensation and at best, complicate fault-finding.
2) Connect via a time-switch. Two 10 minute pumps a day are better than say 30 1 minute pumps as:
quieter, less energy use, possibly less wear, precludes possibility of pressure switch cycling if any pipe joints are weeping.
3) Consider installing via a separate dedicated RCD ELCB to facilitate use of a less sensitive trip e.g. 100mA or 300mA, (if allowed – seek professional advice). Any tripping will then only affect the pump.
These are my own views, i.e. those of an unqualified but informed self-builder. I have not checked them against Hydroforce installation advice.

[Peter GoldieParticipant]

Another thought ref Hydroforce rainwater harvesting pump.
If you do have a fault i.e. earth trip – it may be useful to establish whether it occurs as soon as the pump is switched on or after it has been running a while.
Mine is the latter and points to the pump rather than the wiring.
I think RCD ELCB can be set off by phenomena other than low resistance = excess current to earth.

[Richard BraunParticipant]

Thanks for the ideas. Will note them in case of future problems. We had a new pump installed shortly after our original post and, at the recommendation and cost of the suppliers, had our electrician relay the cable from the pump junction box to the house and to redo the connection box in the house. We have been ok since then (knock wood). If we go away for any period of time we try to remember to turn the pump switch off as our previous problems often happened during such absences.

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