Bypass valve

3 Sep 2006
Reaction score
United Kingdom
I am fitting a smartfit y plan to my exsisting system have done all the trv's.and now need to put in an automatic bypass valve witch will go inbetween my pump and 3 port valve.the fittings on the bypass valve are 22mm . Can I fit the return from the bypass to the 15mm return from my hot water tank? witch gos to 22mm after 6 foot.
ortherwise I would have to take up a lot of floor boards to get to 22mm return.
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With a 3 port valve at least one port is always open.

The by-pass is required on the heating circuit for when/if, all the thermostatic valves shut off in the heating only mode.

The ideal place is to bridge the heating flow and return, anywhere after the pump.
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Sorry should of explained like doitall..., but its a yes anyway ..:)
if u have 1 rad without a trv then u dont a by-pass at all. New regs require the room with the roomstat not to have a trv.
by-pass rads should be fitted with two locksheilds to prevent this problem
A lot of boilers don't require an automatic bypass, check with the boiler manufacturers.

Vaillant have and actual auto bypass for the heating side built in.

Was at Worcester last week they said no need for an autobypass.

Baxi when I did training on their boilers said they had put these little bypass tubes in because installers weren't using bypasses anymore.

There must be many others.
Sorry , if , lookin on a web site is your knowledge, so be it
Moz said:
Sorry , if , lookin on a web site is your knowledge, so be it

I'm sorry but it will only get worse as the dinasaurs drop off. :LOL: :rolleyes:
mos i got told off for takin the p+++ss out of em, some n*b ed will ava pop you watch.

was once told ages ago buy my old college tutor that a by-pass on a y plan was not requrired, dont believe this to be totally true, after all there is a difference between a boiler by-pass and a system by-pass.

anyone have an views on this one?

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