Pulsacoil 2000 Problems

Hi,

Having trouble with my Pulsacoil 2000 - it's sometimes producing warm water, sometime just cold, but it's not been hot in days.

For starters, I've checked the water bucket on top and that's full. And the heat exchanger does sometimes get hot (ish), so I don't think the pump is gone.

I've also taken the front off to check the PCB and the little red light is flashing twice per second when taps are off, but it starts flashing once per second when I turn the tap on, could that be one of the thermistors?

In addition, the unit operates quite noisily. It buzzes when the hot water is on and just after I've turned it off - does that indicate anything?

Also, both the fault and control circuit LEDs are off.

One more thing, I used to be able to hear the water almost boiling within the tank but that has stopped - could there be a problem with the immersion heater as well?

Thanks in advance,

James

Anyone got any ideas?

I'm going to try replacing the two thermistors to see if that solves the problem. Are they relatively easy to replace?

Thanks,
James