My davies craig controller + pump appear to work fine if i switch my ignition on, coming on gently for 10s, and then off for 30. But after two minutes, it all lights up like an xmas tree and the pump goes to full power. Is this normal, what is the reasoning behind it?

thx...

We neveR use the controller unit because it pulls massive amps and as the battery gets hammered the controller goes ape, might be your problem
Regards
Andy

I've noticed the amp draw on my old style d/c controller but I have a cec with a hefty alternator . It's supposed to be 10amp draw but I've seen it pull more like 18 when pulsing .

Ok, well i fired the engine up to see if it would make a difference - it did.

The controller/pump still went ape after two minutes, but then at 2.30 the controller detected a temperature change and then started to operate normally. This was with the engine idling on the driveway so perhaps this wouldn't happen through normal use. Over the noise of the engine I couldn't tell how hard the pump was working though, tempted to put an ammeter/voltmeter gauge for it in the dash.

Why the controller does this quite honestly baffles me though-I am glad I had my plumbing setup to allow some waterflow around the engine thermostat to give it something to pump when it goes mental. Have emailed davies craig after finding nothing online about this diagnostic mode. I will post up what they say - at least there will then be a searchable solution for someone else to find.

Took the car out for a decent test and found a problem -

My water temperature at one point hit red during my last drive at high rpm, despite nothing registering with the davies controller sensor mounted in my radiator.....The davies controller never detected water temps above 75 degrees throughout the drive despite this.

Really trying to figure out what the cause is? Half tempted to just put an r/c model plane electronic speed controller on instead, and control my water pump rpm manually....to me it seems it just isn't worth the bother!?