reversed injection

Kal Row

has anybody had experiance with reversed injection - does it make a difference?

Mark Eatherton1

Reeversed injection done right...

requires that the point of injection be at the bottom elbow, which is actually a tee. It requires the injection pump to flow aginst the distribution flow.

I've never had an occasion to use it. I think it may have been a wild eyed conception of an engineer that thought he had hit upon something different. It would also cause mix and dillution of the water returning to the heat source. Instead of providing the coolest water to the heat source, and the warmest water to the load, it provides both with a really mixed up dillution. Dillution is the solution to pollution, but I'm still not clear about what its positive impacts are as it pertains to closed loop heating systems:-)

You don't see it heavily promoted much by any of the manufacturers any more.

Whats your application?

ME

\"Maine\" doug

ME, I plumbed mine reversed based on

some of your diagrams and explainations. One not so cold days, the 007 injection pump would speed up and slow down even with a valve in the injection return, like it was trying to run at the right speed but couldn't decide. We then piped it with the return to the primary loop after the feed from the 007 and the 007 sounds much smoother but a bit faster. You can feel the blending between the T's.
Is this not OK?

Kal Row

truth be told,

it was and error, it's a big manifold with zones and stuff with not enough wall space, so when i migrated the fig1 to fig2, in 3d, i thought i had to reverse it, It was on a bench and i was looking at it from the top down, it was late and I was tired- we’ve all been there, simple error, but then i thought, you know, maybe i would get smoother mixing like Doug said, so i thought id ask around before i made a decision

Mark Eatherton1

Doug...

The problem is that the small circulator has to overcome the force of not only the main curculator that it is pumping against, but it also has to lift the check valve off its seat. It does cause for a roller coaster ride for the circulator. It looked good in theory, but in practice had some start/stop scenarios similar to what you described.

It ends up doing pulse width modulation on an OVERKILL basis.

Live and learn...

ME