3 port valve stays hot after boiler turns off

[egginyourface]

good day all. Im still a newby on this one.

Got a call from a customer today saying that 3 port valve stays hot after boiler turns off.

Is this normal due to hot water passing through 3 port valve. He reckons he needs to cut power to whole system then renergises and the heat stops??

Heating and ho****er works fine...

is this normal??

 

[egginyourface]

ho****er

 

[wheeto]

Pump over-run taking heat from the cylinder? More info needed though...

 

[dontknowitall]

Many boilers are wired up to have a pump overrun. The object of this is to dissappate the heat through the heating instead of keeping it at the boiler, thus making more efficient use of the heat produced. Older plumbing often has a pipe stat which runs the pump until the hot water pipe drops to the set level.

It will be a problem if it's still running when the pipes are cold and the system isn't calling and trying to satisfy heat.

 

[doitmyself]

Got a call from a customer today saying that 3 port valve stays hot after boiler turns off.

Is this normal due to hot water passing through 3 port valve. He reckons he needs to cut power to whole system then renergises and the heat stops??

It's perfectly normal. There is no need to turn the power off and on.

If the valve has been held by the motor in heating only position (Port A open) and the heating is turned off (thermostat or timer), the valve will continue to be held in the same position until either, (a) hot water is called, or (b) the power is turned off and on. Either of these will reset the valve to HW only position (Port B open).

 

[doitmyself]

ho****er

Some one forgot the space in "hot water"!!

 

[egginyourface]

thanks for the advice all.

And will remember to spell ho****er with a space next time

 

[tipintim]

Some one forgot the space in "hot water"!![/QUOTE
LOL. If I dropped a t and a w and an a and a t I would be on a third infraction. You made my day for observing.

 

[Bat21]

It's perfectly normal. There is no need to turn the power off and on.

If the valve has been held by the motor in heating only position (Port A open) and the heating is turned off (thermostat or timer), the valve will continue to be held in the same position until either, (a) hot water is called, or (b) the power is turned off and on. Either of these will reset the valve to HW only position (Port B open).

This is exactly what my system has been doing for years. If the system happens to go off at night while in the central heating position, the valve stays energised and there is a slight annoying hum (not smell :teeth_smile🙂 to it. If I manually switch on the HW and turn the cylinder stat up you can hear the valve motor release and the spring pulls it back.

Have I been wasting my time all these years by manually doing this? :annoyed: I thought they guy who wired it in had done something wrong. Is this not putting extra 'strain' on the valve motor by leaving it 'energised' all night?

Interestingly, this only started to happen after the old timer was replaced.... maybe all timers hold it this way now?