Bypass valve required ?

3 Jan 2009
Reaction score
United Kingdom
System : sealed/pumped, Worcester 24SBi in garage, Sunvic 3-port mid-position valve, digital room stat etc

Oddity : Worcester 24 SBi altho’ being a combi boiler is installed only to provide CH (i.e., there are no HW flow / return pipes out of the back of the boiler only CH flow/return) and we still have HW cylinder in the airing cupboard

Question : From reading the treads on bypass values they are used to maintain a min flow to the boiler in the event of all TRV’s being shut off.

Fom this can I presume that its only something for the CH circuit and not a concern for the HW circuit ?

And if so as long as I have no TRV on the rad in the room with the room stat I don’t need a bypass ?

Many thanks
Sponsored Links
the sbi24 is a system boiler, the sbi25 and sbi28 are combis, I think the poster is a bit confused which boiler he has ;)
You are right - I am confused !

I have a Worcester 24SBi - and its not a combi !

But question still applies ! Thanks !
Sponsored Links
If it works alright dont worry about it, Although they are now recommended the fitting of them is not generally needed when you have a three port valve.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local