Mike need your help again please!!!

Hi Mike,
You probably won’t recall but I had you come out last September to look into a problem I was having with my pulsacoil 2000 boiler, the water was running cold after only a few seconds turned on.
On the day you came to repair, the boiler was actually working properly by some miracle for the first time in several months and we weren’t able to replicate the problem. You did however replace one of the parts (heating elements I think) as a precaution and also as I was going to be paying the call out charge anyway you said it would be cost effective than having you come out again if it failed! All worked fine afterwards.
However this past week the water is not heating at all when set to the off peak switch (which it has been running off perfectly since you last repaired it). If I switch this off and switch the on peak switch on the water heats but again runs cold after about 5 or 6 minutes. There is no red light flashing, the green light is on steady as always. I have checke dteh fuse etc all seems fine.
I was hoping you may be able to attempt a diagnosis to determine if I need to call you out again or if there is anything else I can try?
Many thanks,
Samiya

Hi Samiya,

Hope you are well. Apologies for my delay in replying! I've been away for a few days. I see you emailed me too... I'll reply to that next :-)

From what you say it sounds as though the off-peak heater element is not working. The pump and electonics are fine because you get hot water after using the day-time back-up heater. You only get five or six minutes of hot water with the back-up heater because it only heats up the top third of the tank (as it uses expensive day-rate electricity).

The question is then why isn't the off-peak heater working? The element itself may have failed but this is not common. It could be leaking and caused the fuse to blow - this is more common. The thermostat may have failed and assuming you've had the overheat thermostat upgrade kit fitted (I can't remember), the overheat protection thermostat may have tripped. You could try re-setting it yourself if you are confident to remove the front cover, find the lower heater element, remove the cover of the element to reveal the thermostat and press in the tiny 'reset' button. You'll need a screwdriver, a pair of pliers and a Biro or match to press the reset button. Probably best if you want to try this to call me, then do it while I'm on the phone to you....

I'll check your email now.

Cheers, Mike

Checking an off peak supply and the element isn't simple. A qualified electrician will need to do the following.

1) Test the continuity between the incoming and out going off the MCB of that circuit.
2) Test the continuity from the consumer unit all the way to the element. (With the spur on the on position)
3) Test the thermostat rod
4) Test the immersion element

(Please check the continuity in the live and neutral cable)

Hope this helps