Gloworm Economy Plus - Banging & turning off when on HW

[kingandy2nd]

Hi all,

We've got an old Gloworm boiler that we were hoping will last us until next year when we re-site the kitchen and get a new boiler installed.

The boiler works ok when the CH & HW are on, but now the weather has warmed up we only what the HW on but when we select the HW only setting or turn the room thermostat down the boiler makes a banging noise (well a few in quick succession with decreasing volume - like something inside is spinning if that makes any sense) and then turns itself off. It fires up again after about 10 seconds and then a few seconds later it bangs again.

Also the pump upstairs makes a really loud rattling noise when in HW only mode.

If you turn the room thermostat back up the boiler then works normally again and the pump quietens down - but I don't really want to be heating the house through the summer just to get HW.

I've got some time off in a couple of weeks so will get a gas safe plumber out then to take a look but I wondered if anyone had seen this before and if its going to be costly to get repaired.

Thanks

 

[Agile]

It sounds as if the pump may be failing or the boiler blocked.

Regardless a competent engineer will be able to diagnose and repair.

Tony

 

[kingandy2nd]

Thanks Tony,

I thought the pump might be on the way out, but it seems to work fine when the CH is on. I would have thought the pump would be under less strain when the CH was off though?

 

[Agile]

The strain on the pump is the same whatever the heat is being used for.

Think of how the flow may vary!

Tony