hot water home?

Post again with the make and model of the boiler. Are there any error lights or messages showing?

As Anon said: it could be the thermocouple (not thermocoupler) but whether there is one at all will depend on exactly whoch boiler you are talking about.

Post a fresh question with enough information for people to look up the make, model and symptoms - or do a Google search or two for yourself.

Acp
August 2017

Could be a dodgy thermocoupler,look it up.

anon
August 2017