Worcester 400 combi

[billy_smith]

Hi all,

I have a problem with this boiler,When the time clock is switched off the rads are still getting warm,not as hot as they would when the heating is on but they are still heating up,There has been another engineer out at it a few weeks ago and he replaced the C/H control stat,What I did notice tonight was,When the hot water stat was set to 3/4 the boiler would ignite and run for a few minutes then stop and then the C/H flow pipe would get really hot,1 minute or so later the boiler would ignite again run for a few mins then stop and fire some more how water up the flow pipe,The boiler seems to cycle in this mode(or at least it did in the time I was there !!)

What I did notice though,If I turned the H/W stat down to 1/2 this cycle did not occur !!

Could this be the problem ??? Or has anyone got any thoughts ??


Thanks in advance

 

[nicknox]

The non return valves by the pumps are letting by so when the pump overrun kicks in (after hw has heated) the rads are getting hot (emptying the heatbank). Get yourself plenty of o rings for this boiler as there a pain in arse once you start to move bits around