Heating System help

[Liam1988]

HI,
Below is a image of my central heating system. It is a back boiler on a solid fuel rayburn (very old system). I recentrly replaced the pump as it had just about packed in, The problems we are having since replacing the pump is that if the pump is turned on when the rayburn is not lit water is pumped up and over the expansion pipe, (pump is the same model as previously and have turned it to lowest setting) today i drained the system slightly to add some senntinel x400 to see if cleaning the system will help. What i dont get after closely inspecting the pipework is that there is a feed into the vent pipe and a feed into the return pipe. Also as it is a very old system the pump is on the return aswell. Any help in making sense of this system would be greatly appreciated.
Thanks



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[Norcon]

Sure you got the diagram right?
And why is the pump being turned on when the rayburn is not lit?

That feed into the vent pipe is not required and if its T'd in below the cylinder primary flow then you certainly have a case for pumping over.

 

[Liam1988]

Sure you got the diagram right?
And why is the pump being turned on when the rayburn is not lit?

That feed into the vent pipe is not required and if its T'd in below the cylinder primary flow then you certainly have a case for pumping over.

The diagram is accurate i have triple checked it.

There are no thermostats to turn the pump on or off, it has to be switched on and off manually, so if the fire goes out the pump is sometimes left on if no one is in.

The feed in to the vent is literally straight from the tank to the vent pipe.

For some strange reason there is also a vent from the return pipe before the pump, which i can only imagine was put in for an air lock

 

[bengasman]

The design is wrong.
The wiring appears to be wrong too.

 

[Nige F]

was the pump very old too - maybe a SMC . Known to be unable to pull the skin off a rice pudding in terms of power But just about enough to get water moving round a few rads on a system like yours . A new pump on setting 1 will be more powerful and show up the design faults in the piping .

 

[Agile]

For some strange reason there is also a vent from the return pipe before the pump, which i can only imagine was put in for an air lock

I dont see that on your diagram?

But you say that the diagram is correct?

What is the F&E tank made from?

Tony

 

[Norcon]

He means the f&e pipe which is as it should be.
A clear and unobstructed path to the boiler!