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Aug 14, 2017
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55
Angus
Member Type
DIY or Homeowner
Hi all. First post from a first time home owner, and very amateur DIY'er.

I've inherited an old Worcester Bosch highflow 3.5 combi boiler when i bought this house.

I'm needing to drain the system to give it a general clean, and to practice for fitting a new towel rail, and unblocking (or replacing) a section of 8mm micro bore to one of the rads, which isn't working properly.

The odd thing with this system is that it seems to have an expansion/header tank in the loft?

I've tried to drain it by turning off supply to the header tank, and opening the drain valve under the boiler - but nothing (not a drop) comes out.

It looks like the boiler is gravity fed, as I can't see any pressure gauges on the boiler itself.

Can anyone with any experience of these boilers point me in the right direction? Is there another valve I've forgotten about - or could it be an air lock or knackered drain valve?

Scuse the ignorance!

Cheers,

Nik
 

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