Not Primary Secondary

Lynne

We are replacing an oil boiler that has three high temp zones, one indirect, and one 4 loop radiant zone. The boiler will be a Smith cast iron. There is not a primary/secondary piping now, and I'm planning on piping a bypass only to protect the boiler from the small radiant zone. Question is, the radiant circulator with manual mix valve is around 17' away from the boiler header; and I want to be sure that the circulator will work. I may be over thinking this. Thanks for your help

tim smith

This is a definite place for pri/sec piping

or you should have a mix valve with return temp protection on this boiler at least I would think. Why are you not piping primary/secondary?? Tim

Lynne

Boiler Bypass loop

instead of primary secondary. I will have a circulator with four zone valves and I would pipe a bypass off of that; mainly to simplify this boiler replacement. The small radiant zone will also have a circulator. I know it's on the edge, but I'm counting on another zone calling when the radiant is on to introduce hot water into the bypass loop for boiler protection. So what do you think of the remote circulator?
Thanks, Lynne

hot_rod

If the radiant zone

is about 1/4 or less (BTU/ hr) of the boiler actual output, generally return protection would not be a must. But to pipe a 3 way thermostatic you would need a p/s or some way to mix supply and returns.

You could use a "dumb" manual mixing valve for a proporitional mix down system. Not as controlable, but less to pipe. Three ball valves properly placed and adjusted would do the same thing. Remembering that the output could vary a quite bit depending on the loads of the other zones.

hot rod

Lynne

1/4 or less of boiler

output is a good rule of thumb, thanks for that. There is a manual mix valve on the radiant zone now, I'm thinking we'll pipe the first circulator that will handle three zone valves, with a bypass just after that circulator, and then a switching relay for the radiant circulator coming back to a 4th zone valve to have the main circ come on and have the bypass flowing. Does it matter that the radiant circulator is @ 20' away from the boiler?
Thanks for the simplification ideas!

hot_rod

Some other ideas

if you go to www.pmmag.com go to archive and Sept 2001. Find the article "a Little Floor Warming Please" Siggy showed a handful of piping options for radiant from a hwbb loop.

It shouldn't matter where the circ is actually located. Be sure to provide a good purge method for the radiant loops.

hot rod