circulator piped in backwards

Empire_2

In my opinion, the 3 phz pump moving in the wrong direction will not produce enough flow. Just look at any impeller and not that it paddles the water, not scoop it in this case. If anything move the water towards the boiler and make sure you PNPC is on the inlet side of the pump.

Mike T.

Sean_27

circulator piped in backwards

Went out to a new job today, Weil Mclain model pfg-7 boiler, armstrong 4270 pump. Not enough heat complaint. Found the return line off the boiler connected to the suction side of the centrifugal pump, the discharge goes up to two branches with balancing valves and out to the baseboard. The supply line comes off the boiler and goes out to the baseboard. It looks like they ran a supply and return line around the perimeter of the bldg, and just tapped baseboard off of them, no diverter tees. Supply line gets to 190 degrees, however the return line never gets above 92 degrees. Found the 3 phase pump running backwards, reversed phase pump now going correct rotation.
I didnt see any flochecks or check valves. I know the thing is piped in backwards, but what would prevent the hot water from circulating in the opposite direction? Would the boiler plates somehow prevent water from flowing backwards from the supply line to the return? Why would the guys that put this in have left it like this for the past 8-10 years? Or did they figure just reverse the pump and cash the check. I know the solution is to turn the pump around and repipe it in.

Sean_27

Mike, I agree that if the pump was going backwards it would no create enough flow. But if I switched phases to get the motor spinning in the direction the pump is piped, why would'nt I set any water to flow thru the system? I realize that it is still "backwards" but would the boiler not allow water to go thru it?
Thanks for th e reply.
Sean

Empire_2

Delta \"P\"

If you have it it will flow. The boiler itself should not impeed the flow itself, but then again, Have you looked at the impeller?

Mike T.

bert

reverse flow

I would definately re-pipe with correct flow direction thru the boiler. Cold reverse return flow can negate the purpose of the limit control. Not a safe situation as is.