Gas boiler insulation?

[jake40]

Hi All,

Had a problem with a blocked heat exchanger on a Barlo Balmoral gas boiler recently which I rectified with help from this forum. However, I've noticed recently that the outer casing of the boiler becomes very hot after 20 minutes and the thermostat appears to cut in even though the return from the rads is relatively cool. The insulation on the inside of the firebox may have become damaged during the earlier work - it would definitely have absorbed some water when removing the heat exchanger. The boiler is heating the water well but not staying on long enough to heat the rads properly. Could the insulation be the problem?

 

[ChrisR]

You suggesting the boiler is losing all its heat through the insulation? Sseems unlikely! I'd be measuring temperatures of the pipes, suspectingboiler stat and more likely, the pump.

 

[jake40]

Hi ChrisR - New pump already installed. Boiler shutting down even though return pipe is cool. If I switch bypass valve to heat the water in the cylinder only, everything works fine until outer casing of boiler becomes excessively hot again. When it is switched to water only, the temp of the return pipe is much warmer before thermostat kicks in. Any suggestions as to why the outer casing overheats? I feel that the thermostat is detecting the excessive heat outside of the combustion chamber and shutting down the boiler irrespective of the temperature of the water in the return pipe. Is this possible?