Camray 5 Combi Oil Boiler locks out on hot water demand

[Seumas]

Having a few issues with my combi boiler, its 14 years old now and due to be replaced as we are building extension, but need to get another 10 months out of the combi yet!
Was having pressure and lockout issues and the relief vale had activated couple times, expansion tank is fuel of water so I have ordered a new one in the hope that will sort that, but not dispatched yet, have ordered new nozzle also as current one been in for around 3 years (yeah I know it should be changed annually...),
I'm now having issues with it locking out when there is demand for hot water, initially it was only doing it when there was no heating being called for, but it's now doing it fairly regularly and even when the heating is on.
Further to that - it is very hard to restart after lockout, as if it has ran dry, but it hasn't and there is plenty oil, took air intake pipe off the snorkel to check clear and all good, oddly though, if I put my hand over the snorkel to restrict the airflow it seems to fire up first time no bother! If I dont do it this way it can take around 10 restart attempts to fire up again.
Anyone have any ideas!?
Could be a week or so before the parts I've ordered arrive so I'm keen to look at what else is going on before then - intend to check pump tomorrow morning after turning everything off to let it cool.

 

[SimonG]

Yes, get somebody with the right equipment to have a look at it.

 

[Seumas]

Yes, get somebody with the right equipment to have a look at it.

Thanks, wish I'd thought of that.....

Should maybe have added, I live on an offshore Island, plumbers with the right equipment aren't exactly falling off the trees here, if we had any trees. So more often than not things need 'bodged' to keep them running till we can get the right equipment, I normally get by and can get most things running again, but I'm running out of bodges this time!
Had the digital thermometer on the flow & return pipework earlier and they are both sitting at around 50, which has me thinking pump has indeed failed and that is just residual heat from boiler, will check that out properly tomorrow.
Pump has failed on me before though and it was never causing lockout?

 

[SimonG]

OK then, good luck with it