feed and expansion tank

[Alasdair213]

I have just replaced my immersion tank (indirect from coal fired back boiler) and having completed that (finally!) I turned all the water back on and have now found that the vent into the expansion tank won't stop running, the expansion tank has been overflowing out the overflow and I'm left scratching my head ...

... the fire's not been lit and the pump is off so I'm not sure what's going on or why. Any help greatly appreciatted, thanks in advance.

 

[Slugbabydotcom]

have now found that the vent into the expansion tank won't stop running, the expansion tank has been overflowing out the overflow

EDITED:-
Are you sure you never replaced it with a direct one?

 

[Alasdair213]

Thanks Slugbaby, I'm pretty confident that that's not the case, although you've got me worried now ... any other suggestions?

 

[Lagerkhan]

Water will find it's own level so you must have something higher than that vent pipe pushing it out if as you say the pump and fire are not on ?
Is there another tank higher ?

 

[Alasdair213]

The main cold water tank is situated slightly higher (although this is as it has been since before I started doing any work on the system).

I've noticed that the vent stops when I turn the valve from the cold water tank off. Also, I've found that turning the pump on stops the expansion tank overflowing, although the vent continues to flow ... don't know if that means anything?

 

[Slugbabydotcom]

Have you accidentally fitted a 'primatic' [single feed and vent]? These are classed as indirect but not suitable where you have an exp. tank. The details of the cylinder are usually on the label.

Are you sure the water is coming out of the vent pipe and that it isnt a problem with your ballvalve?

 

[Lagerkhan]

I've noticed that the vent stops when I turn the valve from the cold water tank off.

OH dear

Are you sure you have the right cylinder ?

 

[Alasdair213]

I have just managed to double check the cylinder type (physical check) and can see the heat exchanger inside ... it IS the right tank ... thankfully!

I have also plumbed it as is was before, i.e. same as the old one ... so what's going on, somebody else has suggested that it could be to do with water pressure coming from the mains, valves open too much or something. Would this make a difference?

 

[Lagerkhan]

If you have fitted an Indirect cylinder as you say ?
Then it must be faulty or it could be a Primatic ???
Does it say Primatic or single feed cylinder ?

 

[Alasdair213]

Nevermind, just figured it out, I think

The last tank was an old one and the heater exchanger entered and left the tank on opposite sides, I believe (and have yet to check) that the exchanger on the new one enters and leaves the cylinder on the same side ... I've plumbed it wrong ... I'm going away to cry now ...

Thanks for the help, it helps just to talk these problems through sometimes

 

[Lagerkhan]

Nevermind, just figured it out, I think

The last tank was an old one and the heater exchanger entered and left the tank on opposite sides, I believe (and have yet to check) that the exchanger on the new one enters and leaves the cylinder on the same side ... I've plumbed it wrong ... I'm going away to cry now ...

Thanks for the help, it helps just to talk these problems through sometimes

Oh dear !!