Problem with Potterton Housewarmer back boiler

wendyjo1

Hi everyone.
We have an old Potterton Housewarmer back boiler in our property. Not energy efficient I know but can't afford to replace at the moment. The hot water is fine but the problem is when put the pump switch on for the heating nothing happens! You can usually hear a gurgling sound when the pump is switched on but theres nothing. Hubby 'bled' the radiators but that didn't help either.
Any suggestions (apart from the obvious rip it out and get a new one) would be most welcome.

Also in regards to getting quotes for a new boiler system do you think it would be better to get them in the summer months rather than winter? Wonder if this would reflect on the prices.

Thanks