Hot water not consistant

Hot water runs hot and cold but not all the time and boiler goes into overheat are these linked

Boiler or Boilermate into over heat?
Hot water sounds like a sensor problem or the DHW pump.
Mike
MGC/H2O
Norfolk

Mike, thanks for getting back to me, the boiler goes into overheat (Potterton Suprima 70l) but not all the time have changed overheat sensor in boiler. I have moved wiring on sensors and hot water been ok for few days, you can bet when my wife runs next bath same will happen hot cold water. Will order both sensors as prob will fail again could it cause boiler to over heat now and again.

Regards
Garth.

Hi;
Could be sludge in the boiler
Or the boiler pump on the BM 2000.
Or a fault on the Potterton boiler.
Make sure the BM2000 bo9iler pump is on number 3.
Feel the pipes on the boiler, are they both hot?
Flow and return that is.
Listen at the boiler and the BM for water noises.
Is the unit full of water?
Drain some out and check it is taking water.
A few ideas for you.
Mike
MGC/H2O
Norfolk

Mike,
Thanks again have checked pipes both hot, pump on boiler mate running and no noises will drain a little out to see if refills. Since i moved sensor wires hot water seems to have run hot even when wife ran bath so in good books at moment. Boiler has only tripped on overheat once in last 24hrs so must be something intermittant will just have to keep checking all.

regards
Garth.