expansion tank overflowing problem

[little al]

i have a siezed gate valve in line to the bottom of the expantion tank, this pipe is overflowing the ball cock valve setting and thus overflowing, i believe i need to replace this siezed valve but what position do i need this to be in closed or not once fitted?


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[kevplumb]

shouldnt be a valve in the line to the expansion tank
and if there was it wont be the cause of an overflow

 

[little al]

shouldnt be a valve in the line to the expansion tank
and if there was it wont be the cause of an overflow

I can feel water pressure coming from this pipe at the bottom of the tank

 

[kevplumb]

when ?
what sort of system boiler etc ?

 

[little al]

when ?
what sort of system boiler etc ?

starts overflowing when central heating kicks in, ideal w boiler.

 

[kevplumb]

and the system is
gravity hot water ?
fully pumped y plan or s plan ?
1 tank or 2 in the loft ?

 

[little al]

and the system is
gravity hot water ?
fully pumped y plan or s plan ?
1 tank or 2 in the loft ?

hot water gravity, 2 in loft, what is y and s plan?, the pump is however mouned upside down!

 

[kevplumb]

in what respect ?

 

[brumylad]

which tank is overflowing, the big one or the little one?

Have you just had a new pump fitted or made any other changes to the system that started the overflowing problem?

 

[little al]

which tank is overflowing, the big one or the little one?

Have you just had a new pump fitted or made any other changes to the system that started the overflowing problem?

little one, had new pump fitted recently, grundfos ups 15-60 on top speed

 

[PEDANTICVINDICTIVEMAN]

Pump too big, why do people keep buying 15/60s instead of 15/50s,.

 

[kevplumb]

so why was it fitted "upside down"

 

[little al]

Pump too big, why do people keep buying 15/60s instead of 15/50s,.

would decreasing the speed help?

 

[kevplumb]

cant do any harm

 

[brumylad]

(sorry I was a bit slow writting this post now I'm out of date)

Doh !

First thing, try turning the pump to the middle or lowest setting.

DO NOT close the gate valve.

Other possibilities: Are you sure the float controled valve in the expansion tank is not dripping, it sounds like the volume of water in the expansion tank is to great and overflows when the water expands as it heats up?

try running the system with cold water (boiler turned off) and see what happens then.