ECR International G95V Installation Manual And Operating Instructions page 43

NOTE: On initial startup, the drain trap assembly will be
dry. A dry trap will allow flue gases to flow through the re-
covery coil drain, which will prevent the condensate from
draining from the recovery coil. If enough condensate ac-
cumulates in the recovery coil, the recovery coil pressure
switch will sense this condition and break its electrical con-
tacts, and extinguish combustion. If this takes place, the
induced blower will stop after a brief post-purge cycle, the
condensate will drain out and fill the trap. If the thermostat
is still calling for heat, the ignition sequence will start again
after a 5 minute wait.
SEQUENCE OF OPERATION
1. Room temperature drops causing the room
thermostat call for first stage heat by connect-
ing "W1" to "R". The control verifies the limit
switch is closed and both low and high pressure
switches are open. The control energizes the in-
duce draft motor on high speed and waits for
the low pressure switch to close. The inducer
remains on high speed and begins a 15 sec-
ond pre-purge period. The high pressure switch
is ignored. If the low pressure switch does not
close within 60 seconds, the control will flash
"2" on the red Status LED, and de-energize the
inducer for 60 minutes.
2. When the 15 second pre-purge time has
elapsed, the control energizes the HSI output
for a 5 second warm-up period (10 seconds on
retries). The control energizes the low main gas
valve. 4 seconds after the gas is energized, the
control de-energizes the HSI output and leaves
the gas energized another 1 second for flame
proving. If flame is present at the end of trial for
ignition time, the control leaves the gas valve en-
ergized, inducer on high speed, and begins heat
blower on delay. The control always ignites on
high inducer/low gas and ignores second stage
call for heat until low heat is established for
15 seconds.
3. Blower on delay time begins when the gas
valve is energized. The control provides the
ECM (Electronically Commutated Motor) low
heat speed signal when flame is proven, and
starts a 30 second soft start (slowly ramp up)
blower delay before full capacity blower level.
4. When there is a demand for 2nd stage heat
from thermostat W2 or automatic staging, the
control changes the inducer from low to high
speed. When high pressure switch closes,
the control changes indoor blower speed from
Low heat to High heat and energizes high gas
output. If the High pressure switch is open the
Green LED will flash. If the High pressure switch
is closed the Green LED will be on. High gas
valve drops out while High pressure switch is
open because it is directly in series with the High
pressure switch.
5. When the thermostat W2 call ends and W1
remains (two stage thermostat), the control de-
energizes the high gas output and immediately
changes inducer speed from high to low. With
the thermostat heating contacts open (single
stage thermostat), the flames extinguish imme-
diately and the inducer blower stops after a 5
second post purge time.
6. Blower off delay is handled by the ECM
(Electronically Commutated Motor). The control
de-energizes the ECM heat signal when the gas
valve de-energizes, and starts a programmed
soft stop (slowly ramp down) delay period.
IN THE EVENT OF FLAME FAILURE:
If flame is lost, the control de-energizes the gas
valve within 2 seconds, switches the induced draft
motor to high speed (if not already on high), and be-
gins timing the inter-purge delay. The indoor blower
motor will be energized and/or remain energized
on heat speed for the programmed delay off time.
When the inter-purge delay is over, the control will
re-cycle up to 5 flame losses (4 re-cycles) within a
single call for heat before going into lockout. The
control flashes "8" on the red LED if lockout is due
to too many flame losses.
CHECKING FURNACE INPUT
The natural gas supply pressure should be a maxi-
mum of 7" w.c. and minimum of 5" w.c. The burner
manifold pressure is factory set to 3.5" w.c. High
Fire, 1.5" w.c. Low Fire. The input rating of the fur-
nace is based on 1000 BTU/cu. ft. gas with a spe-
cific gravity of 0.6.
Since heating values for the gas vary geographi-
cally, the actual furnace input and output will vary
accordingly. For example, natural gas with a 1000
BTU/cu. ft. heating value will reduce the input to
93% of the rated input. Natural gas with a 1100
BTU/cu. ft. heating value will increase the input to
approximately 103% of the rated input. This is not
usually a problem; however, adjustments to com-
pensate for this can be made by minor adjustments
to the burner manifold pressure or by changing the
burner orifice size.
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