Primary/Secondary Pumping

GW

I thought it was 6", or 6 times the pipe diameter. Were did you get 12?

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Darren_2

Primary/Secondary Pumping

My boss wants to do primary/secondary pumping at his house. The heating system is already existing with several zones of baseboard and soon to have two zones of radiant staple up. The circs are mounted on the return. My question is can I add a circ after the spirovent and before the tees for the zones and wire it so that it runs when any zone calls for heat? I plan on tying the supply and return headers which are 1 1/4 black iron together with 1 1/4 copper. Will this work or do I need to repipe the boiler so that I am pumping away with everything.

Thanks Darren

GW

more please

I'm not quite with you... if you're going to do a p/s, you'll certainly need a primary pump, as you know. And yes, after the spiro is best. Having it come on when any zone comes on is OK, but if you're installaing radiant, aren't you going to have constant circulation?

If you talking from a p/s standpoint, there really is no "pumping away", that is the term used when you're talking about conventional zoning. With p/s, obviously the supply would be better off with the pump on it.

I guess you'll come off for the hi temp zones first, then the low temp for the radiant? This will allow for smaller pipe sizes on the primary, because you're stretching out the delta t

gary

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John@WattsRadiant

Primary/Secondary

If I'm following what you're saying, the supply and return tees for the existing baseboard are going to be too far apart for a p/s set up. The problem is water will take the path of least resistance and might flow through baseboard zones when they are actually off. I think you're going to have to do some more repiping, making sure the supply/return for the baseboard zones are 12 inches apart or less, then the same thing for the radiant zones. If you can post a drawing that would be very helpful
John

S.D.

Primary Secondary System

Darren,
Buy Dan's book! I found it very easy to understand and written in plain english without any extra bologna.
short and sweet

Shawn D.

jim f

i thought it was 4 times the pipe diameter

John@WattsRadiant

12\" or 6\" or ???

I have seen all three numbers mentioned (4 & 6 times pipe dia, 12") as well as about 5 or 6 others. I think the best practice is to get the tees as close together as physicaly possible. If you're putting a full-port ball valve in between to allow a power purge from the boiler, it's hard to keep them closer than 12 in sometimes.

Arthur

P/S System

I've always felt the pump Before the sipro vent is better as then there is less likehood of 'sucking' air in especially when the hot is very hot and cavitation was likely.
I've always been more in favour of pumps on the return for the same reason too.

Arthur

P/S System

I've always felt the pump Before the sipro vent is better as then there is less likehood of 'sucking' air in especially when the hot is very hot and cavitation was likely.
I've always been more in favour of pumps on the return for the same reason too.