QHT Boiler manual 3WOOD boiler piping and wiring Considerations

3WOOD boiler piping and wiring Considerations

Before choosing a particular system for your installation, the possibility of using a mixing valve arrangement to avoid the problems of overheating should be considered. These systems will continuously release heat to the distribution system in proportion to the outside temperature or other load factor. Such an arrangement can be added to any heating system, and is one of the most sophisticated methods of heating system regulation available. We strongly recommend a mixing system with all of our solid fuel systems.

A.3WOOD AS THE ONLY BOILER

The 3WOOD boiler can be used as the only boiler in your heating system. Of course, the disadvantage of the installation is that there will be no automatic back-up system for times when the solid fuel fire will be unattended. For automatic switch-over from solid fuel to oil or gas, a tandem hookup of the 3WOOD with a second oil or gas boiler is recommended (see Section B). The obvious advantage of this set-up is the cost saving involved in the elimination of the conventional boiler, controls and piping required. It should be noted that the 3WOOD boiler is extremely efficient when fired with wood or coal. Many people use the 3WOOD boiler in conjunction with direct vent gas or electric space heaters located in the living spaces.

The following outlines a typical installation of a stand-alone 3WOOD boiler in a system planned for solid fuel firing.

1. The supply tapping goes to the heating radiation. Install a “tee” with a 1” branch in the line to the radiation, as close to the boiler as possible. This branch tee should point up and will route the piping to the “dump zone”. There must not be a valve or any potential restriction between the boiler and this tee.

2. in the boiler supply piping, install an air purger and expansion tank sized to handle the water in the distribution system as well as the 3WOOD boiler.

3. Pipe the make-up water into the boiler through a Watts 1156F fill valve (pressure reducing valve) into the lower rear ½” tapping at the bottom of the boiler.

4. Install a tee with a 1” branch for the dump zone in the return tapping. Point the branch of the tee up.

5. The circulator should be installed in the return line from the heating radiation. The return is piped into the boiler through the running end of the tee.

6. A circulator relay, Honeywell R845 or equivalent may control the circulator. Both the room thermostat and the Overheat Aquastat installed in the 3WOOD boiler control this relay.

NOTE: In a case where the thermostat is calling for heat and boiler fire is out or otherwise unable to meet the heating demands of the house, the circulator will continue to run. This has the advantage of helping prevent the water in the system from freezing if the house temperature drops below 32F. If the circulator is deactivated, the system must be drained if subfreezing interior temperatures are anticipated! As an alternative to draining the system, a mixture of heating system, anti-freeze (propylene glycol) and water can be used in place of normal water in the system. Such a mixture should only be added after the system is thoroughly checked for leaks.

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