low hot water pressure after draining gravity-fed system

[lauren144]

Hi,

My plumber drained the hot water from gravity-fed system so that he could move pipes in my ensuite. Since re-filling the system, there has been no / very low hot water pressure. there is intermittant flow through my gravity-fed shower in the bathroom, this has a pump fitted - i wondered if it was to do with that.

Our guess is that there is an air lock somewhere in the system - does anybody have any ideas of what the problem might be? and how to fix it?

Thank you

 

[Sussexenergy]

Hi Lauren,
if you were to look in your loft where your cold tank is, you will probably find that the cold feed
pipe to your h/w cylinder rises slightly before it drops to your airing cupboard. This is a common płace
for an airlock on your hot pipework. I have had success in the past by carefully leaning on or shaking the pipe. Another way is bung the open vent pipe over the cold tank and sucking with a wet vac on the tap in question.

 

[Ermintrude]

Lime sale or lump of insulation in top of cylinder

 

[zzzjim]

Did you see where he drained hot water from ? ( checking not upset crud at bottom of cylinder ! )