Hi all. CH fails to work on timed / auto. Constantly seems to cavitate.

[Ukstealthbomber]

Ideal Icos HE18.
Y plan.
Ok when on constant.
Set to auto and when firing up of an evening, banging and clattering.
Any suggestions pls?

 

[RoryD]

Can't imagine that being set to auto will bring "banging and crashing". This inducates overheating. Working on constant only indicates a clock issue.

 

[Ukstealthbomber]

Can't imagine that being set to auto will bring "banging and crashing". This inducates overheating. Working on constant only indicates a clock issue.

Hi mate.
To explain better:
Works fine when left running set to constant. All valves , thermostat, pump etc operating.
Leave home in the morning and turn to auto.
Come home and no heating on. Wait and boiler fires up then loads of water dropping in pipes and banging at boiler. After about 60-90 seconds boiler stops.
Have a filter above boiler when is clean.
If i drain off above boiler water is full of air - let this run for 10 /20 mins till no air then it will fire up and run ok.
Next day, all repeats itself! ???

 

[RoryD]

Hi mate.
To explain better:
Works fine when left running set to constant. All valves , thermostat, pump etc operating.
Leave home in the morning and turn to auto.
Come home and no heating on. Wait and boiler fires up then loads of water dropping in pipes and banging at boiler. After about 60-90 seconds boiler stops.
Have a filter above boiler when is clean.
If i drain off above boiler water is full of air - let this run for 10 /20 mins till no air then it will fire up and run ok.
Next day, all repeats itself! ???

Water dropping? I presume you can hear the water gurgling through the pipes. I'd say there's a blockage in there somewhere (sludge). The constant/ auto thing might just be a red herring, I really couldn't help you there. The banging and crashing indicates overheating which will be pump, blockage, air..
In reality there needs to be an engineer stood there because there are limits to problem solving via forums. Give it a dose of fernox F5 and run it. If it works let us all know here, beyond there I can only wish you luck