Worcester 28i rsf no hot water

[Jax teller]

So you've got another external vessel plumbed in or has a radiator been left with sufficient trapped air to act as a vessel?

No sorry, my boilers expansion vessel is flooded, it kept dropping pressure so the engineer suggested flooding it to stop this rather than replacing it as apparently its a nightmare to replace on my boiler?

 

[ianmcd]

If the heating pipe is getting hot with hot water running then it is the PCB

 

[Jax teller]

If the heating pipe is getting hot with hot water running then it is the PCB

A relay or something in the pcb causing the boiler to cut out you think?

The water and heating obviously stop when the boilers cutting out.

 

[ianmcd]

the way your boiler works is that when you run a hot tap the power to the pump is cut to allow all the heat to go to the Bi-Thermal heat exchanger to heat the water, a relay is sticking and supplying power to the pump when HW is demanded, not all boilers work this way but yours does

 

[Jax teller]

the way your boiler works is that when you run a hot tap the power to the pump is cut to allow all the heat to go to the Bi-Thermal heat exchanger to heat the water, a relay is sticking and supplying power to the pump when HW is demanded, not all boilers work this way but yours does

Ok makes sense.

Circuit board needing replaced again then. Just to confirm before i order it, heating and hot water stops working when the boiler cuts out (flame in tell-tale window goes out) in your experience this will be a pcb fault?

 

[ianmcd]

switch the heating off and run a hot water tap, if boiler fires flow switch is fine and then see if the boilers pump is running with only HW demanded if it does its the PCB

 

[Jax teller]

switch the heating off and run a hot water tap, if boiler fires flow switch is fine and then see if the boilers pump is running with only HW demanded if it does its the PCB

Is there an option to just switch heating off or do you mean switch boiler off?

When boilers off no hot water, when i turn the heating right down to minimum and try water, it only runs hot for a minute or so then gas cuts out and shuts boiler off.