Heat exchanger/forced air on baseboard zone

drosner

Hi All - I inherited a home with many additions over its 150 year life. One problem i'm having is in the kitchen addition that was added 10 years ago. The prior owners cut a lot of corners when building the addition including the heating cooling. This is a relatively large space and has lots of windows and doors - so it gets quite cold in the mornings.

When I did some investigation I discovered that the t-stat only controls the air handler - and has no connection back to the circulator pumps at all. Then I traced all the piping and found that the heated water supply to the air handler is on the end of a line of baseboards in another part of the house. So to get the kitchen warm I have to crank the heat in the other room and then make sure the blower is running in the kitchen.

2 questions...

1 - Assuming I am ok with the kitchen being the sole location for the thermostat for the entire zone (kitchen and other area) - is this as simple as splicing the right wires from the stat to my Taco control unit? That way when it calls for heat it not only starts the blower but also the circulator pump for the zone.

2 - The kitchen is an area that is very occupied and needs heat most of the time - while the other room on the zone does not. Ideally i'd like to create a new zone for the kitchen air handler. I actually have an existing zone that isn't used and I was thinking I could just get a plumber to connect the air handler to that. Then I can take the current line that goes to the air handler and connect it directly to the return side coming out of the handler (basically by passing it). Does all of that work in theory, or are there things about the air handler that would be different than baseboard that I need to worry about?

Any help or gotchas appreciated before I start to talk to plumbers to make the updates....

Jamie Hall

Both options work -- in theory. The better of the two is to take the zone which you are not using and run it to the air handler in the kitchen. You would want your plumber to hook up both the supply and return of that unused zone to the air handler, and then take the baseboard zone and run it back to the manifold by itself. Don't try to combine the two returns; that can create some odd flow problems.

That said, how is the system piped near the boiler now? The arrangement described above would probably be best with zone pumps, rather than zone valves, so you could set the flow rates for good delta Ts and heat delivery.

drosner

I've got taco circulators for each zone - 005 series I think or what looks like their basic cartridge circulators.

I didn't know I could control flow rates at the circulators. If my circs have that as an option does that allow me to fine tune heat in different zones? On cold mornings when all zones are going there are some zones that is want to take priority. In fact of my six zones only 2 really need propriety and it would be good to dial down th heat in those other Zones.

Does more flow mean hotter or more heat transfer or the other way around?

Jamie Hall

How much and if you can control the flow with pumps depends on the pumps. With any kind of luck someone else will chime in on that. If there are also ball valves, though, you can reduce the flow with them.

On flow rate -- increasing your flow rate will decrease the delta T and vice versa. The heat transfer is determined by the amount of radiation, the input temperature to the radiation, and the delta T, since the heat output is related to the amount of radiation and the average temperature of the water flowing through it. It all interacts, but it makes sense if you stop and think about it for a while...