boiler bypass piping

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Tim,
I dont have the ability to send a picture right now, but i agree with your thoughts and I appreciate your response

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boiler bypass piping

I was looking at an old gravity system that had been converted and it had a bypass line around the boiler.
the pump was installed pumping away from the expansion tank.the bypass line tee (on the supply side)was located between the boiler and the expansion tank. It was then connected to the return line just before it entered the boiler. Is return water flowing around the boiler? does this work? I can understand it if the bypass line was initiated after the pump but how much help is it in the above described location?

Timco

It sounds of little use, but a picture would help. I would think the suction of the pump and the pressure at the return would cause it to flow from return to supply. Some installers see the dotted line between supply & return and think a pipe is all that is needed to get a bypass. I have seen it before and when viewed with a thermal camera, you can see the flow is opposite of what was desired.

Tim