overflow

[gdrummond]

have domestic tank overflowing.fitted new cylinder ,header tank and new sealed system boiler about 2 years ago . never have to fill up sealed side (heating) but water pours out of domestic overflow and i mean pours like the coil in the cylinder has gone,had 5 new ball valves, overflow connection 5 inches below ,watch hot water expanding up cold feed which is the correct way for a cylinder but it keeps rising. normal y plan.i have 31 years ex ,had 2 gas technicians and 5 plumbers round who i know ,still pours out overflow any ideas?8i think it has to be the cylinder but customer has never topped up the filling loop in 2 years. cheers Graham

 

[ProffesorPlumb]

Tough one that is - would be interested myself to know the outcome

Hang on, are you saying there is an open vent on a sealed system?

 

[buster]

Hi, The system described does not make any sense.

 

[ajs heating]

shut off the mains stopcock see if it stops.
if so sounds like your have a faulty mixer valve or monobloc tap passing cold water mains to gravity hot water.
faulty non return valve.

 

[TerryH]

My appetite has been whetted....... what was the solution?

 

[ajs heating]

you won't see him again. got his advise

 

[Tosh]

Ooh I say AJ,

Harsh but true I feel he he he he

 

[tonyn]

shut off the mains stopcock see if it stops.
if so sounds like your have a faulty mixer valve or monobloc tap passing cold water mains to gravity hot water.
faulty non return valve.

had same problem last week was a faulty mixer shower , cold water passing the hot check valve

 

[WHPES]

If you never needed to top up the filling loop it isn't water from the primary circuit leaking into the DHW side as if it was, the pressure would drop. Sound like a faulty non-return valve to me.

Shouldn't the feeds to mixer showers / mixer taps be balanced?