rules of thumb

Mike T., Swampeast MO

Don't know if there is a "rule of thumb" but people seem to start getting concerned if a single zone is much less than 25% or so of the load.

Assuming 75% efficiency from the 175,000 input, you have output of about 131,000.

The kitchen rad (11,000) is only 8% of that modified load. If that zone called by itself you would certainly have some severe short-cycling.

Some possibled "fixes" that aren't too expensive.

If the kitchen is OVER-heating, install a TRV on the kitchen rad ONLY and make certain that the t-stat is in ANOTHER space.

If the kitchen is UNDER-heating, install TRVs on every rad ON THAT ZONE and put the t-stat in the kitchen.

If the kitchen is part of the "downstairs" zone you mentioned, that will be about 23% of the load and I [think] you'll be OK.

stan_2

rules of thumb

Does anyone have any rules of thumb when zoning a house for hot water heat? My customer wants to put his kitchen radiator on a zone of it's own and put the rest of the floor on another zone. The kitchen radiator has an output of about 11,000 btu's and the rest of the floor is about 30,000 btu's. There are three other zones in the house and the boiler input is about 175,000 btu's. I'm not sure if this is economical or not. Should I be concerned about firing this boiler just to satisfy the kitchen?

Unknown

Master zoning

This might be a job that you could use master zoning.

Simply put, it means hooking up the thermostat to the zone valve for the kitchen, but not tying it to the boiler control.

The zone is on it's own thermostat, but only runs when some other zone calls for the boiler to run. Two zones run at once.

I like this idea for small zones.

Noel

Mike T., Swampeast MO

Sounds good if that "slave" zone is relatively oversized (or well balanced) compared to the "master" but what happens if the "slave" is undersized?

Unknown

Counting on diversity

If you only have two zones in the house, it might be an issue. This will team up with ANY zone calling.

Think about this....How many minutes of the hour are ALL zones OFF?

She'll run with the first zone that calls, then the second, then the third. Should be enough diversity to do it.

Or add some baseboard.

I love this place.

Noel

Mike T., Swampeast MO

Thanks Noel

Now I see where you're coming from. It's a "slave" to the SYSTEM as a whole, not a particular zone.

Sorry I didn't read more carefully the first time...