weird system

15 Nov 2006
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United Kingdom
working at a property today.servowarm 'heat only'boiler downstairs with pump next to it,all behind a swing-out radiator.looked in the loft at the top of this 3-storey terraced house and found the header tank minus one expansion pipe!followed the cold feed from the tank down into the bathroom and into a radiator!has anyone got a clue how this system has worked fine until the gas valve blew on the boiler?
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welcome to the wonderful and interesting world of old servowarm boilers

great aint they

the old ones did not have an expansion pipe, just used feed for both

some of them aint got ballvalves either, used to have to go into the loft with a watering can

lots of systems dont have open vents, especially servowarm systems. very dangerous if the CF blocked but wouldnt stop it working.

servowarms never attach the mains to the F+E imagine using your mug to fill a whole system.
Because the cold feed is also the expansion pipe there is always movement of water which stops it ever blocking . Perfectly acceptable if in manufacturers instructions
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thanks lads,thought i was missing something.i'm gonna rip the boiler out put in a worcester 18ri and turn it into a sealed system.

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