A Well Designed Forced Hot Water Heating System

It's all in the piping


Properly piped multi zoned forced hot water heating system


There are several advantages to installing a multi zone heating system rather then a single zone loop, that runs the hole house on one thermostat.

First of all, a single zone system will only allow you to raise or lower the temperature of your home all at once. There is no comfort here if several people would like rooms at different temperatures, it's impossible to accomplish.

Multi zone hot water systems allow us to install a thermostat wherever we want it and then connect the radiation in that area and only that area to to it's own thermostat.

This is repeated throughout the house with as many zones as we want. Each zone will have a feed line leaving the boiler and going through the radiation on that zone and then back to the boiler. Manifolds will be built at the boiler with enough tee's to accommodate how ever many zones you may have.

Many components are also installed within each loop and several pieces of equipment that are common to any system. Below is a list of items that would be common to each zone in a multi zone hot water heating system;


Below is a list of components found in all hydronic hot water heating systems;


So Hows It All Work

Warm Water Wonder

OK so now you know what you need to have a multi zone hot water heating system, how about a little about how they work? We'll start at the boiler where it all begins.

First thing that happens when the thermostat calls for heat in any zone, is click on the switching relay it's wired to. This relay in turn calls in your boiler. The boiler fires. Thats where it all starts and as the boiler begins to heat the water a few other things also join the mix.

Your relay also calls the respective circulator pump for the zone that called. This makes the pump come on and water begins to circulate out of the boiler and through the radiation within the room that has the call.

The boiler will not boil the water, as would be assumed by the name, it only runs up to about 200 degrees and shuts off. There is a high limit cut out wired in, to make this happen on temperature rise.

When the temperature within the boiler gets to the high limit set point, it shuts off and goes into standby. Waiting for the temperature to go down. Now why would the temperature go down? Because the circulator pump is still running and transferring the heated water through the radiation so that the convection process can heat your room. The water then goes back to the boiler to get reheated and this action will cause the boiler temp. to drop and bring on the boiler at low cut in set point.

All of this happens automatically and continuously with low voltage wiring coming from your multiple remote thermostats wherever they may be to the boiler.

I have linked the components above to detailed articles about each component. I also have an extensive library of heating related articles here at info Barrel. Please feel free to browse my user profile.

Properly piped multi zoned forced hot water heating system
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