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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.
3WOOD boiler piping and wiring Considerations
