SWITCHED LIVE IN BOILER?????????

[garyptong]

HELLO.
THIS IS MY FIRST ATTEMPT AT THIS SO LETS HOPE IT GOES OK.
I HAVE A PROBLEM WITH MY CENTRAL HEATING PUMP RUNNING CONTINUOUSLY, ALL THE TIME THE CENTRAL HEATING IS SWITCHED ON AT THE TIMER.
IT KEEPS RUNNING EVEN IF THE BOILER IS NOT RUNNING. I KNOW YOU HAVE A RUN ON ON MY BOILER FOR THE PUMP, BUT IT WILL STILL BE PUMPING 10, 15, 20 MINUTES AFTER THE BOILER HAS SWITCHED OFF.
WHAT I CANT WORK OUT IS, DOES THE BOILER GET A SIGNAL FROM THE ROOM THERMOSTAT TO SAY THE ROOM IS AT THE CORRECT TEMP. AND THEN SWITCHES THE BOILER OFF, WHICH SHOULD THEN ALSO SWITCH THE PUMP OFF (AFTER THE PUMP RUN ON TIME HAS ELAPSED).
IS THIS CONTROL BY THE 'SWITCHED LIVE' TERMINAL IN THE BOILER AS THIS SEEMS TO BE LIVE ALL THE TIME?
HOPEFULLY, ONE OF YOU KIND PEOPLE CAN PUT ME OUT OF MY MISERY AND EXPLAIN WHAT THE 'SWITCHED LIVE' IN A BOILER DOES.
MANY THANKS,
GARY

 

[shambolic]

Please stop shouting (turn capslock off)
What make of boiler is it first?
This will tell us if it has a pump overrun built in with the boiler thermistor or PCB.
All the overrun does is when the boiler switches off power from the switched live it has a relay built in to keep power on to the internal pump (or wired out to external depending on boiler and set up) for a set time to allow the heat exchanger to cool down.
So give us boiler model first ta!!

 

[garyptong]

Baxi solo 3

 

[Aquaheat]

sounds like the relay for the pump overrun is sticking on the PCB then.

 

[garyptong]

We have had a new pcb fitted 1 month ago?

 

[gas4you]

If the s/l terminal is live all the time you need to check your zone valve/s.

Sounds like the microswitch has stuck on it it.

Room stat tells the valve to open, valve tells the boiler to fire.

Pump over run should be approx 6 mins on this boiler.

 

[baxpoti]

Pump overrun is approx 8 minutes, time it.