The issue we have is with an aircon condensate pump.
sauermann si 1730
Pump is basicly a solenoid piston pump.
Uses a float sensor for activation with a magnetic float and I suspect reed switches for level sensing.
The main control board consists of a small 240V to 12 transformer with basic rectification and filtering. The reed switch sensor effectively, through possibly an optoisolator, switches two relays, one for an alarm and the other for the solenoid pump.
The pump short cycles and is actually probably overrated for the aircon unit.
We did have a smaller pump originally but found on the real humid days at start up it would not keep up with condensate removal so the aircon man fitted this bigger pump.
The 12v/240V relay that switches the pump seems to burn out its contacts and fails every year. I have been replacing it with a higher rated set each time and am now up to 10amp 240v rating.
The solenoid pump does not operate direct on 240v but has a single diode in line for half wave rectification effectively giving it 50 pulses a second on the pump.
I have tried a solid state relay with zero cycle point switching but it was not successful I suspect due to the in line diode.
Would be interested in hearing your possible solutions.
Every time it ends up happening at night or on a weekend or when I can't get anywhere to get parts so have to run a hose into a bucket....