Glowworm Xtrafast 120 Overheating

[ngms27]

Hi my Xtrafast is overheating with fault code 05.
The Overheat safety thermostat has to be manually reset to make the boiler operate again.

This is intermittent.

Any ideas what this could be?

 

[AshaDPlumber]

Just turn the boiler stat down for the time being until you get a boiler engineer to it. If the stat is down it should cycle on and off before overheating. It's probably air, the water cant get round the exchanger quick enough so is overheating. Try bleeding anywhere you have a bleed valve

 

[GasMan1965]

F5 Overheat fault..

Overheat stat operated
Maximum temperature exceeded
Check thermistor connections
Air in system with thermistor at maximum setting
Faulty overheat stat connection

 

[GforceJames]

Had this problem recently turned out to be a blocked up secondary plate heat exchanger.

Easy enough to change.

HTH

James