Primary secondary secondary

chippy2

hi

I’m converting a single zone baseboard to a primary and two secondary’s. Secondary’s will have their own circulators. One will be the existing baseboard loop and the other will be a radiant floor heat manifold. Both using closely spaced Tees.

My question is on the primary loop. Is there a minimum recommended length for the loop and a low speed pump? Primary would only be boiler, expansion tank, air separator, fill/drain valves, air vent, etc

Thanks

EdTheHeaterMan

Not really. I have done this with as little as 5 feet of 1" copper. 2 ft out 1 ft for the U-turn and 2 foot back The closely spaced tees were installed on one of the 2 ft sides.

You will have 2 sets of closely spaced tees and will probably use the higher temperature zone take off first. The lower temperature radiant heat will be the second take off. Just use enough pipe so you have enough room to get to all the parts that need service. It's not a contest to see how little pipe you can use.

The pump needs to be able to move the proper GPM thru the short piping systen and the pressure drop of the boiler. If you are moving less that 19 GPM a Taco 007 should work unless the boiler requires a higher head.

mattmia2

If you do it mostly with threaded parts you will need less space to be able to cut things out and replace them.

hot_rod

Dedicated series primary fig 4-8 loops are not so common any more.

Here are some parallel primary piping ideas, a hydraulic sep fig 6-8, gives you air, dirt, magnetic, and hydraulic separation in one "box"

A mix device would pipe off the trunk on the secondary side