Hot Water Issues

[Radiator woes 34]

Evening, I wonder if someone could give me some advice regarding my hot water system please.

I have an system condensing boiler attached to an unvented hot water cylinder to supply my hot water. I removed a towel rail on Friday which is fed by the hot water cylinder rather than central heating to allow plastering and painting. I managed to remove the towel rail without a problem, isolating it and draining it etc.

However since reconnecting the towel rail my boiler keeps cutting out on poor circulation after a few minutes and the pump attached to the cylinder sounds like it is struggling.

From what I have read, I have managed to introduce air into the system and it must be released. However from what I can see there is a small screw cap on top of a vertical pipe above the pump but when loosened only a tiny amount of air was released.

Is there anything critical I am missing here. I'll have to call a plumber otherwise. I cannot see the pressure that my boiler is operating at it but the expansion vessel from the cylinder is on 0 bar.

The boiler has no problem heating the radiators by the way but I believe that is a separate system.

 

[twgas]

That 0 bar of pressure will be the system pressure, i'm assuming the gauge is next to the vessel. There is, possibly next to the gauge, a filling loop, a braided hose with an isolating valve at one end, and either a non return, iso or a valve incorporating both, turn it (them) on til the gauge reads about 1bar.

 

[Radiator woes 34]

Thanks for your reply. The pressure gauge is immediately next to the red pressure vessel. There is a piece of braided hose connected to a white pressure vessel which I assume is to fill the cylinder.

I will try what you mentioned to see if I can bring the pressure up to 1 bar. Is it possible that the pump also needs bleeding if it sounds like it is struggling. The pipe work below the pump is hot but cold above it.

 

[Phill Peck]

Your towel rail is connected to your htg system but on the hw circuit. You have drained the water out of your htg system fill it back up and test.

With any luck you havnt done permanent damage to the boiler and pump running the system dry

 

[Radiator woes 34]

I will try and refill as advised. The heating seems to be working fine however, boiler fires up and runs no problem and all radiators in house heat up and stay hot.