Newbe help please !!??! not sure if mines a 9kw or 12kw so posted in both

Hello Everyone,

i really hope someone can help !

This is the scenario

- got home from holiday
- noticed boiler off and trip switch in hall was down.
- thought it must have been something else that tripped switch , ie kettle so flicked it back on
- bolier powered back up
- thought all was ok
- no hot water in taps or rads
- started researching on the net
- took cover off
- electronic display as i cycled through was something like 21, 20 , 17 then some random shapes.
- checked the two 30 amp fuse holders.
- voltmetered them, one fuse from the left holder (rear one i think) had blown
- got new fuse
- turned on, started heating up as the first display went up to 34 with the second display 1 or 2 degrees behind it (happy!)
- now spotted that the left side connector block with the thick red wires going into it has a lot of burnt marks around one of the ingoing wires
- second reading now reads "Er"

so.... looks like i have some level of heat and hot water but im concerned about the burnt looking connector block
also, have read that one of the dual elements can fail causing a low level of heat to be suppplied., ie running at 50%

if anyone has any thoughts or suggestions i would really appreciate them, i simple cant afford to call anyone out and am fairly technical minded so would really like to fix it myself.

surely there is a freindly expert out there somewhere !!??

all the best

Andi

Hi Andi,

You need to measure the resistance of the heater elements to start with. If you get around 13 Ohms for each then they are in good condition. Anything else and that's your problem.

It sounds to me as though one of your relays is overheating too. If so, it need replacing. This alone could be the problem. Some basic voltage tracing or continuity-testing with a multimeter will isolate the fault. You say you are technically minded so this should be easy enough for you to figure out the details of how to do this. I've already given you the pointers in my answers to your emails....!

Cheers, Mike