Jack SUPER SJ125, Owner'S Manual

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TO THE INSTALLER
It is necessary to ensure that there is sufficient air flow through each furnace after the add-
on installation has been completed. It is suggested that the temperature rise method be
used since most installers are likely to have the necessary equipment. The temperature
measurements may be made using a potentiometer and thermocouples, mercury thermome-
ters. If thermometers are used, sufficient time must be allowed for the thermometer to reach
actual temperature. As much as twenty minutes may be required.
PROCEDURE
To check the existing system, drill a hole 1/4” in the side of the return plenum on the primary
furnace and a similar 1/4” hole in the side of the main supply air duct, 24” from the supply air
plenum. Insert a temperature measuring device in each of these holes and start the primary
furnace. Allow the furnace to operate until all temperatures have stabilized. This will take at
least 1/2 an hour. Read the two temperatures thus obtained and not the difference, TS - TR.
(see diagram 1, page 18). This difference should not exceed 85 degrees F. (29° C)
Complete the installation of the Jack as an add-on furnace and drill a third 1/4” hole in the
TA (See TA, page 18). Insert a temperature measuring device.
Operate the primary furnace until the temperature rise TA - TR across the primary furnace is
equal to or less than 85 degrees F (29° C). Should this temperature difference exceed 85
degrees (29° C), increase the blower speed until the temperature rise TA - TR is equal or
less than 85 degrees F (29° C).
Shut off the primary furnace and build a fire in the Jack unit. When the fire is established, fill
the fire box to the top of the firebrick (maximum level). Open the combustion blower air
damper. Allow the temperature to stabilize and measure the temperature difference TS - TR.
Should it exceed 85 degree F (29° C), a further increase in blower speed will be necessary.
Once the proper air temperature rise has been obtained, an ammeter should be connected
to the blower motor to measure current draw. If it exceeds the name plate rating, change the
motor to a higher rating (if the old motor was a two stage, ensure that the new motor is as
well). It is permissible to change the blower motor and blower drive pulleys in the primary
furnace but not the blower unit.
This equipment must be installed according to the manufacturer’s instructions and in a man-
ner acceptable to the regulatory authority having jurisdiction by mechanics experienced in
such a service. When required by regulatory authority, such mechanics shall be licensed to
perform this service.
Safety Statements
8