vokera mynute 12-48 rse stops heating system after 2 - 3hrs

[conrad1]

OK..

i switch on my boiler and the central heating works well for 2 - 3 hours, but eventually starts cooling down. The boiler keeps running, but is just not heating the system.

If i switch it off then on again, it works for another 2 -3 hours, then starts cooling..

The pressure is fine, the thermostat is set to just above mid level.. it's worked fine for the last 12 months, but now i have this issue.. any ideas?

 

[conrad1]

Last night, on switching on the boiler, it would fire up, then within 30 seconds, the flames would die...

This morning, the boiler kicked in at 6am on the timer and did not die, but it took about an hour to heat up the heaters, which eventually began to cool.

 

[conrad1]

I upped the system pressure - the recommended pressure is between 1 adn 1.5 bar, which i had it set to reach when the system was running at full steam.. I spoke to a local plumber who siad that the pressure should sit at just over 1 bar when cold... it rises to over 1.5 bar when running but thats ok apparently. problem solved.