BAXI BOILER GRAVITY FED - NO WATER SUPPLIED TO PUMP????

[buddyboy123]

Hi guys,
have a pre council house with Baxi back boiler and gravity fed hot water system, over the course of a few days we started getting funny noises coming from pump and some banging of pipes which in the end resulted in no hot water and no central heating, I'm a mechanic to trade so just assumed the pump was on the blink as it feeds both systems via Honeywell motorised valves (one of which i just replaced about 2 months ago) anyway, I ordered the new pump and went to fit it but on removal of old head it seems as if its fine, and there's no water gushing from pump point, tried turning the isolating screws back and forth but still no water emanating from pump housing? very strange as to why there would not be any water. Before removing pump i turned hot water and central heating on and i can hear it fire up no probs but then get funny noises from pump and pipes bang sporadically, any ideas guys would be greatly appreciated by myself and my freezing cold family! lol.

 

[sooey]

Ball valve stuck in the f&e or a blocked cold feed, no water in the system.

 

[ianmcd]

Sounds like you have a blocked cold feed, in your attic you will have a small tank that fills the heating system there will be a pipe at the bottom of the tank usually 15mm follow this to where it connects to the heating system and if you get some sort of magnet see if the magnet is attracted to the copper pipe where they join if it does this is where the blockage is as the magnet will be attracted to the magnatite inside the pipe

 

[Netdragon]

These old systems are prone to cold feed becoming blocked and boiling away the water.
Check tank is full of water, if so open rad vent, no water means blocked cold feed.

If there is water and pump valves are opened and can push finger in then either air lock or blocked pipes.

 

[buddyboy123]

The council carried out renovations a few months ago, i've bought my house but the guy downstairs hasnt and his tank was in my loft with my tank, seemingly when they removed his tank they shut his tank off and mine and never turned mine back on, so for last few months i've been boiling the system dry filling all the radiators with air! we've been freezing in this house for two weeks during one of the coldests months in over a year! ah well, the engineer sorted it for me in a few minutes and had heating back, we thought it was something serious and ordered new pump!

 

[Hugh Jaleak]

You're lucky you've only needed a new pump! Running a boiler with insufficient water at best can wreck the boiler, at worst present an explosion risk!

If it ever starts banging then turn it off immediately, classic sign the boiler is overheating through lack of water and/or circulation.