08/30/2007 6
EI203
MECHANICAL INSTALLATION STEPS
DOWNFLOW
NOTE: Please refer to drawing EA104, revision E or newer for proper placement of the HeatChoice unit
when an A/C coil is installed.
1.
If the DOWNFLOW furnace is setting directly on the floor, the furnace will have to be raised for insertion
of the HeatChoice unit. This will require a field designed and constructed plenum. This plenum must have
sufficient strength to carry the weight of the existing furnace.
2.
Depending upon model, the ideal plenum size for the HeatChoice is either 15” x 18” or 18”x18”. Therefore,
this base plenum should be sized according to the HeatChoice and the hot air discharge hole on the bottom
of the furnace. It should NOT be sized according to the outer dimensions of the furnace (see drawing
EA1Ø4).
3.
Examine the hot air discharge hole in the bottom of the downflow furnace. Assuming 18” model, if it ranges
between 18”x18” to 19”x19” (if 15” model adjust accordingly) the HeatChoice unit can be installed directly
beneath the furnace if there is no A/C coil installed. This plenum need only be about 11” high. If the
bottom hot air discharge hole is less than 18”x18”, use 15” model or allow at least 6” between the bottom of
the furnace and the top of the HeatChoice unit (see drawing EA1Ø4).
4.
The HeatChoice is designed with a special double plate at the element mounting. Cool air from the bower
must blow between these two plates. Therefore, the Elector-Mate must be inserted into the base plenum
such that the mounting plate is even with the edge of the hot air outlet hole. Do not necessarily line up the
HeatChoice control box with the furnace cabinet front. The concern is the hole in the bottom of the furnace
mating with HeatChoice elements.
5.
Cutting the correct hole size in the plenum – locate the supplied cutout template marked “UAI012”. Once
placement of the HeatChoice is determined, tape all four corners of the template to the plenum.
Make sure
that the template is squared off to the plenum before proceeding to the next step.
Using a utility knife
cut out the appropriate dashed line on the template. Then use a marker to trace around the area cut out of
the template. Remove the template from the plenum and proceed to cut the hole into the plenum.
6.
Extend the “V” channel to butt against the plenum surface opposite the 8”x18” hole. After HeatChoice
insertion, a sheet metal screw may be installed to attach the back plate of this “V” deflector channel.
7.
Insert the HeatChoice and properly screw to base plenum. If the base plenum is 15” or 18” wide, side
supports will be needed on the side for proper attachment to the HeatChoice.
8.
When using A-coil with a bottom discharge furnace note the vertical spacing requirements on drawing
EA104. Allow as much separation as possible between HeatChoice unit and A-coil drip pan.
Also encourage using the 15” model and add baffle constructed as shown on drawing EH101.
