How to microzone effectivey?

Constantin

Set up the system to run on one circ and have TRVs on the emitters to allow you microzoning down to each radiator. Once the supply temperature becomes a non-issue (due to the TRVs), you can use one pump for both zones (if it can move the requisite amount of BTUs around).

Less expensive and probably more desireable is putting in a buffer tank as Chris suggested as it'll give your boiler a rest between firings. Use an outdoor reset controller to run the tank temperature, then let the zones sip as needed.

Saratoga Development

How to microzone effectively.

I have a Baxi which I have a 18,000 btu baseboard loop and a 15,000 BTU radiant loop on the same floor in an open floor plan. I have a seperate pump for each because of the different temperatures. How do I stop the boiler from short cycling? Should I run on thermostat to control both pumps and locate the t-stat centrally? I want to avoid short cycling the 105,000 BTU boiler.

J.C.A._3

2 words...

Buffer tank.

Store the btu's and have them used when needed. I know it seems like a waste of a great resource,(a fine boiler) but with such a low load it makes sense. Space is the only thing that would stop me from recomending it to SO many jobs that I see. Chris

Plumb Bob

Sure; each pump doesn't have to have its own stat. If they call for heat about the same amount of time each day, you can run them off the same stat or maybe even link one orboth of them to one of the other (bigger) zones' stats.

If zone X calls for heat much more than zone Y, there may be ways to wire your relay box so that the zone Y stat runs both zone X and zone Y, but the zone X stat only runs zone X. That does not eliminate short-cycling but it does reduce it.

You can also equalize the run times somewhat if you can adjust the water temperatures separately in each zone.