can you see what wrong with this system? (boiler)

14 Nov 2007
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United Kingdom
Went to a 3 beds house to do a refill and test. House been empty for 3 months. Heating will not work correctly. Boiler fire for 5 seconds then cut out then fire again for 5 seconds without tripping overheat.

Can you see what wrong with this system? :LOL:

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Which direction is the pump making the flow?
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the 15mm return, and the pumping down on an ov system, are two things that aer wrong for me...
Could do with a bypass but what is the flow connected to on top of the boiler ?
Does the return reduce to 15 mm?


pump speed is at max, but couldn't take heat away from boiler quick enough. return pipe from upstair radiators ( 5 ) in 15mm toward to below where it join downstair radiators ( 5 ) in 15mm before tee off to cylinder return to boiler.

also, there is 3 faults. 1. pump is not connected to boiler overrun. 2 con pump run all the time even it is empty 3. no bypass.
I am glad that I saw it first but to be fair the picture is far from clear.

More concerning is that there is no gas supply pipe visible but he did say that it would fire up!

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