Injector tee

[Dannyparty92]

Just a question I'd like to ask regarding a post I read earlier. If you have a solid fuel boiler with pump heating and gravity hot water. Would there be three pipes leaving the boiler two being the flows and one being the return? And when the return from the heating and hot water are commoned would this be where you would use this injector tee fitting. And if one was not fitted would the return from the heating instead of going back too the boiler return go to the gravity hot water return and stop circulation?

 

[AWheating]

yes injector tee is used to connect the returns together at the stove, it stops the pump having too much effect on the gravity circulation when running.

 

[tamz]

If you don't fit an injector tee on a commoned return, the pumped return will affect the gravity circulation.
If the boiler has 4 tappings and you take separate flow and returns the pump is very unlikely to affect it as the boiler acts like neutraliser.

 

[SimonG]

Amazing how a decent picture paints a thousand words.

 

[Best]

It keeps the gravity circulating & in the proper direction. Without it, the pumped rad circuit would still work fine.
It seems to be a requirement of stove manufacturers to fit an injector tee. Tbh, nothing wrong with a 4 pipe arrangement to boiler with pipe stats fitted, although it will tend to not heat the cylinder while pump is running.

 

[snowhead]

It seems to be a requirement of stove manufacturers to fit an injector tee.
.

It's so they can sell you one of thier own expensive T's.
Instead of leaving you to make up your own out of fittings, as AW pic shows.

OOH sorry, cat and bag etc.

 

[Best]

Getting slightly away from the reasons for an injector tee, but thought I would mention this, - an injector tee can actually have the reverse effect unfortunately - when the gravity circuit is only working with no pump going, the pumped pipework can heat up to some of the rads. Seen this with gravity fed free standing boilers which were correctly piped & using injector tee. Not good when you don't want any rads on!

 

[Dannyparty92]

Thank you all for your help once again .