Back boiler with no header tank

[owington]

Hi,
A neighbour has asked me to look at a radiator that is cold in the middle. I assume this is a build up of sludge so was going to try draining the system and removing radiator to try and blast through with a hose or add some cleaner. When looking in the loft there is only one header tank. When running the hot tap this begins to fill again. Once full i began to drain some water from a radiator and again the header tank begins to fill. There is only one vent pipe and it is a back boiler. Is this normal?

 

[gassafe]

Sounds like you have a primatic cylinder. Google it!

 

[owington]

thanks for the reply. Is it ok to turn cold water mains off and drain fully or will this result in the air pocket dissapearing?

 

[kirkgas]

the air pocket wont dissapear it will fill the whole tank, then when you refill it (slowly) the air bubble will be recharged at the top of the cylinder, sometimes the air bubble is syphoned through by filling too quickly from empty, simply part drain the refill slowly, once fully refilled it will work again with cold feed valve fully open

 

[owington]

thanks mare will give it a try

 

[Kev the gas]

Just dont add inhibitor as the bath water wont need any bubbles !

 

[shorticus]

Just dont add inhibitor as the bath water wont need any bubbles !

although I did once hear it's very good for exfoliating :rofl:

 

[owington]

Hi,
I have followed the instructions and slowly filled the system with the bath hot tap open. Upon firing the boiler away everything seemed fine and i had clear hot water coming from the taps. There was a lot of air passing through the pump on the CH circuit so i knocked of the CH and immediately there was a rush of air in the cylinder and when running the taps again the water was brown. Is there anyway to get the air out of the CH circuit and what am i doing wrong. Thanks in advance for any replies.

 

[Billy Bob Bob]

you just have air in the system try venting the pump and rads the discolored water should settle its to be expected draining a old tank and primatic cylinder

 

[owington]

thanks mate, so i shouldnt need to drain and refill the system again?

 

[Billy Bob Bob]

thanks mate, so i shouldnt need to drain and refill the system again?

no,think about it you have drained the header tank there will be rubbish in the bottom of it which has just been stirred up and drawn into the cylinder it should clear after a while just keep a eye on the pump vent it as required you dont want it to burn out due to air entrapment

 

[owington]

Just wanted to say cheers gasman. All up and running following your advice.

 

[WHPES]

Bit of a rarity now. Never seen a primatic for years (well they are rubbish aren't they?)

 

[Billy Bob Bob]

Bit of a rarity now. Never seen a primatic for years (well they are rubbish aren't they?)

oh yes

 

[owington]

hopefully first and last. Still, live and learn.