Sequence Of Operation - ECR International GTM Series User's Information Manual

T
HE FURNACE SHOULD BE OPERATED WITH
. N
ALL PANELS IN PLACE EVER OPERATE THE
FURNACE WITH THE BLOWER
REMOVED EXCEPT FOR SERVICE PURPOSES
The furnace achieves its mid-efficiency
in two general areas. First, there is no
wasteful standing pilot. The furnace
consumes no gas in between cycles.
Secondly, the furnace is designed to
allow very small amounts of excess air
in the combustion process. Older fur-
naces had heat exchangers that were
commonly 40% larger than necessary
for complete combustion. While this
prevented the creation of carbon mon-
oxide, the heated excess air was ex-
pelled up the chimney where it could
not benefit the interior of the home.
Special safety controls now prevent the
formation of carbon monoxide.
IMPORTANT
Your furnace should be cleaned and
inspected annually by a trained and
qualified service technician.
Your service technician has the knowl-
edge and test equipment to determine
the condition of your furnace.

SEQUENCE OF OPERATION

1. Thermostat, responding to cool
room, calls for heat.
2. Combustion air blower begins.
DOOR
.
3. After 15 second pre-purge, hot
surface igniter warms up.
4. After approximately 5 seconds, the
gas valve will open, and the burn-
ers ignite.
5. Thirty seconds after the burners
ignite, the main blower starts on
the heating speed.
6. System remains in this state until
the room air temperature rises
causing the thermostat to termi-
nate its call for heat.
7. The gas valve shuts off; the burn-
ers extinguish.
8. After brief post-purge period, (5
seconds), the combustion air fan
stops. The main blower continues
to run.
9. Approximately 2 minutes after the
burners extinguish,
blower stops. Elapse time ranges
from 60 seconds to 150 seconds,
depending on the installer's ad-
justments.
10. The furnace remains idle until the
next call for heat.
VARIATIONS
If your system includes air condition-
ing, your thermostat (supplied by the
installer) will likely have two switches.
The first switch is the system switch.
The switch settings usually include
HEAT, COOL, and OFF. Some ther-
mostats have system switches which
include HEAT, COOL, AUTO, and
OFF. The system switch must be in the
HEAT or AUTO position for the furnace
to run.
The second switch is the fan switch. It
usually has settings of ON and AUTO.
The fan switch may be in either posi-
tion when using the furnace. If the fan
switch is set to ON, the main blower
will run continuously, and the blower
delays mentioned in the sequence of
operation points 5 and 9 will be ig-
nored.
the main
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29785 R3 3/10/2004