Pump Away and the Make Up Line

neilc

I've got a boiler that is not pumping away from the tank which I intend to correct.
Where the tank is now I have a tank isolation valve and tank drain.
Where I want to place the tank, I have a valve isolating a short stubbed capped line from previous repiping.
I mention this cause it makes it easy not to have to drain the system, I have these 2 isolations already inplace.
Moving the tank is the easy part.
Now my question.
How important is the location of the makeup water line?
Most drawings show it at or near the tank.
What happens if it is left tied in after the circ?
It would still feed 12# when circs are off, correct? (yes)
Or is it worth piping to the new tank line?
(I do not think I have enough valving on the makeup line to avoid the drain pain.)

Jamie Hall

Tied in after the circ. is probably fine, since the circulator will raise the pressure and keep it from feeding. Problems arise when it is before the circulator and the tank is after -- then you can get some really wild overfill situations. But you should be OK.

EBEBRATT-Ed

It has to be on the same side of the circulators as the expansion tank. That's all that matters. Near or at the expansion tank is best but a reasonable distance is ok

Jamie Hall

EBEBRATT-Ed said:

It has to be on the same side of the circulators as the expansion tank. That's all that matters. Near or at the expansion tank is best but a reasonable distance is ok

Ideally I quite agree. However, in practice so long as the feed line never "sees" a lower pressure than the system static pressure you shouldn't get an overfeed condition.

Further, I see I may have misunderstood the OP's comments, but I think what I read is that the feed will be after the circ. and the tank before. In which I case I still think he'll be OK... not ideal, but OK.

neilc

thanks guys,
now I need a picture cause I don't actually remember where that feed is,
I just see that easy way to swap the tank location.
stay tuned.