A95094
VARIABLE SPEED CONDENSING FURNACE ALGORITHM
Using recorded Low Heat (LH)
and High Heat (HH) values,
calculate the Heat Load (HL)
using:
HL=(228 X LH) + (350 X HH)
Is HL < 3648?
Is HL > 5600?
Is 5600 > HL > 3648?
Calculate Low Heat (LH) on
time will be 16 minutes.
Calculate Low Heat (LH) on
time will be 0 minutes.
Unit will initiate the next cycle in
Low Heat for a maximum of 16
min. before initiating High Heat if
the call for heat still exists.
Unit will initiate the next cycle
in High Heat until the
thermostat is satisfied.
Unit will iniate the next cycle in
Low Heat to the nearest minute
for a period of time as calculated
by the following:
LH = (5600 - HL)/122
The next cycle will be initiated
with the calculated Low fire run
time before initiating high heat if
a call for heat is still present.
run time
Is there a call
for heat?
The Low Heat and High Heat
run times for this cycle will be
as calculated.
Thermostat is satisfied.
Yes
Yes
Yes
FEBRUARY 1995
47
