boiler is Weil McLain Gold CGa.
current circ pump is Taco 007-F5, installed on return side, pumping water down, and into the boiler.
I'm pretty sure this pump is under-sized, as the specs list a max head of 10 feet, and this system is used for heating the second floor unit of a 2-unit apartment. vertical distance from boiler to 2nd floor is wall over 10 feet, more like 16 feet. the apt has baseboard elements, but the temp in the unit never gets above 62-65. boiler temp is set at 220.
I'm looking to replace the 007-F5 with a Taco 009-F5, with a listed max head of 35ft. BUT, the 009 has a max flow of 10 GPM, compared to the 007's 23 GPM. Does this "upgrade" make sense??
Thanks in advance.
.jim.
Best Answer
The Maximum head of the pump is not to push the water up to the radiators, it is to overcome the friction loss of the flow of the water in the system. The installed pump should be large enough for your heating system. The water in the system is held up to the highest radiator by the water pressure in the system (look at the pressure gauge mounted somewhere on the boiler) A rule of thumb is 12 psig for a 1 story house, 15 psig. for a 2 story house and 20 psig for a 3 story house. Turn the boiler system off, go to the highest rad and open the vent. If you get water out then the pressure on the boiler is okay.If you can't get the temperature high enough check for water in the rads or baseboard units, vent all the air that may be in the heating elements. If all this fails call a boiler co. to fix the problem. One more thing, if you screw up and install too large of a pump you will get noise in the piping or radiation.