How much head?

hr

Unless the boiler is a 55K and you are at design conditions, expect some cycling. Low mass boilers especially are prone to some short cycles when they are micro loaded.

hot rod

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jesus colon

How much head?

jesus colon

How much head?

Can someone with siggy's software help me out. New boiler, seeing a temp drop of 30-35 degrees across zone 1 and boiler short cycling, wondering if circ is too small. 55K btu/hr heat loss on that zone, 1 inch copper M pipe, 150 feet long, 12 elbows, 4-45 degrees, B&G EASB-Jr air seperator, and 3 ball valves on that heating circuit with 10 cast iron rads with monoflow fittings. Currently a taco 007-ifc. I think I may have to move to a pump with higher head pressure? what do you think? Thanks Marty

John Ketterman

Short-cycling isn't reduced by increasing the flow.

If you double the flow, you have twice as much water to be heated per minute, but half the delta-T, so the boiler doesn't feel a difference.

If the boiler is short-cycling, it is probably too big. I assume only one zone is calling...it is too small for the boiler (as already pointed out above). If you can merge it with another zone, that will make a difference. The deltaT is a separate matter and 30-35F is not a problem in itself, it is fine.

Marty_12

head question

The boiler is a buderus 115-3 section, with a riello F3 (.6 nozzle at 175 psi 0.80 gph (slightly overfired for DHW needs). Outdoor reset logamatic and usually only the one zone calling for heat (other zone is ~ 40k btu/hr heat loss). So am I hearing that a Taco 007-ifc circ is fine for that length of pipe and # of elbows? Thanks to all.

jeb

Can you really have too much head?