Again it is about the most efficient exchange of heat, I realize that most conventional's pull from the top, I am saying that either way is OK with me but I find the B-L series gets very hot in the top and for higher temps it may be better to return to the top on that model, all my 250's return to the bottom as that is the hotter area. Neal look at the burn chamber of an oil boiler, they typically return on the bottom and rear, they typically supply from the top front, same theory that I am promoting here.
I should have mentioned in my first post, that I wanted advice,te return would be best on top or bottom, pertaining only to the P&M BL OWF's.
I appreciate all your comments & they all are valid. I guess my main concern is keeping the condensation down to a minimum on the surface of the firebox. After installing my BL & starting it up this fall, I intend to run my high temp at, 180 F with a differential of 10 degrees.
Slimjim, your point is well taken, may I ask, with the new BL series, that include refratory cement on the bottom third of the firebox sidewalls & ends including fire bricks onte grates, would the return water heat up more quickly closest to the refractory cement (bottom), as the refractory cement & fire bricks will retain a quite a bit of heat, even at idle? My dealer had recommended having the return to the top, he had said the water at the top is the hottest so when the cooler water return, the extra heated water will act as a buffer incoming cooled water.
I want what is best for my large investment & to be good to my stove. After manufacturing P&M conventional OWF's for 30 years, I would think by now they would have worked out all the clinkers & pretty certain they have. I'm thinking it may be best if I go by their recommendation on water line hookup
oaky