Stuart Models Clack Valves

[David HeahParticipant @davidheah47239]

Will they work with injectors?

[David HeahParticipant @davidheah47239]

Good evening all,

My boiler is fitted with 5/16 x 26 clack valve mounts (presumably the maker wanted course threads to avoid cross threading, or perhaps he just had a set of BSB taps and dies!)

Stuart Models offer a 5/16 x 26 threaded clack with 3/16" pipe connection – so a straight 'plug and play' available.

Can anyone advise what the lift of these clacks is like, and if they are suitable for use with injectors (11oz or 3/4 pint).

Kind regards,

David

[Boiler BriParticipant @boilerbri]

Hi. My 5" Brittania is fitted with the same size and they work ok. If the lift is a bit tight it will increase the velocity of the. Water going in and restrict the flow a bit but should be ok otherwise.

Bri

[julian atkinsParticipant @julianatkins58923]

5/16" x 26 tpi seems very big to me for a 11 oz per min injector. A check valve of 1/4 x 40 tpi connnections with 1/8" dia seat and 5/32" ball would be quite adequate.

Cheers,

Julian

[David HeahParticipant @davidheah47239]

I am less concerned about the valve being too large; more so concerned about it being too small and causing back pressure on the injector. A decent injector should be able to create ample hydrostatic pressure to lift even a larger ball check valve.

As I am working with an existing boiler, replacing the soldered bush would precipitate further inspections and generally unnecessary work – I'll place an order with Stuarts. Thanks Boiler Bri for your confirmation on this application

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