ICP N9MP1, Руководство по обслуживанию

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Single Stage Multi Position Furnace
Service Manual
20
440 08 2001 02
The “CONTINUOUS” terminal of the ST9160B control is en-
ergized ONLY when there is NO OTHER CALL FOR OP-
ERATION of any kind. If there is a call for HEAT, COOL, or
“FAN ON”, this terminal is DE--ENERGIZED. The purpose
of this terminal is to provide a means of air circulation during
“OFF CYCLES” at a different speed than either heating or
cooling. The use of this terminal is operational, and there
will be no speed tap wires connected to this terminal
when the furnace is shipped.
“CONTINUOUS” fan should not be confused with “FAN ON”
which is obtained by switching the fan selector switch on the
thermostat sub--base to “ FAN ON ”, (energizing the “ G ” ter-
minal) which causes the blower to run on the “ HEATING ”
speed.
The ST9160B Electronic Air Cleaner terminal ( EAC ) IS
ONLY energized in conjunction with the HEATING and
COOLING speed terminals. The maximum allowable con-
nected load to the HUM terminal is 0.8 (eight tenths)
Amp.*
*The combined connected loads of the EAC and HUM termi-
nals cannot exceed a total of 0.8 (eight tenths) amp.
24. HONEYWELL SV9541M GAS VALVE/IGNITION CONTROL
dwg 25--23--31a
Figure 30
Honeywell ST9541M Ignition System
Gas Valve/Ignition Control
Ignition/Sensor
Pilot Burner/Sensor
The system consists basically of only two (2) components.
The Ignition System Control and the Pilot Hardware. The op-
erate on Two (2) 24 volt power circuits received from the
ST9160B Fan Timer/Furnace Control. One is the power sup-
ply to the ignitor, the second is to activate the ignition se-
quence.
The Ignition System Control manages the ignition sequence,
and the flow of gas to the pilot and main burners. It is in es-
sence a combination Gas Valve and Ignition control.
It contains sophisticated electronic components (internally)
and has NO USER SERVICEABLE COMPONENTS.
Should a problem be verified internally within the device, IT
IS NOT REPAIRABLE, and must be replaced.
The Pilot Hardware includes the pilot burner, the hot surface
element that lights the pilot burner, the flame rod that senses
pilot flame, and the cable that attaches to the system control.
The hot surface element is made of tough
break resistant ce-
ramic composite material. It operates on 24 Volts A.C. The
Igniter/Flame Rod assembly can be replaced independently
from the pilot burner assembly.
The system operation is quite simple, and forgiving (I.E. nui-
sance lockouts are eliminated)
25. HONEYWELL SV9541M SYSTEM OPERATION
Connecting the furnace to the line voltage supply with the
blower door interlock switch closed provides 24 volts to pow-
er the system. (This is accomplished by the connections
from terminals [pins] #4 & #2 from the ST9160B fan timer to
terminals #1 & #3 of the SV9541M gas valve.)
When the thermostat calls for heat, (the combustion blower
starts, causing the pressure switch to close completing the
circuit to the ignition system control) there will be approxi-
mately a two (2) second delay, while the ignition system con-
trol runs a self check.
Part of the self check is to see if a flame signal is detected.
If a flame signal is detected upon a call for heat (and naturally
there shouldn’t be), the ignition system control will energize
the electronic fan timer output (causing the conditioned air
blower to start after the fixed 60 second “ON” delay) and will
keep the valve and ignitor to circuit off.
Assuming that no flame signal is detected upon the call for
heat, (Normal operation), the ignition system control will
power the ignitor circuit (24 volts) causing the ignitor to heat
up.
If the ignitor circuit is not proven (I.E. the ignitor is missing,
broken, or the connections are loose) their will be no re-
sponse from the ignition system control. (Lockout)
Once the ignitor circuit has been proven, and the ignitor be-
gins to heat up, the pilot valve will be energized allowing gas
to flow to the pilot burner.
With the ignitor now hot, and gas flowing to the pilot , the pilot
should light, and the sensor should sense flame.
If no flame is sensed, (I.E. no gas, pilot not lit, flame not en-
veloping sensor, etc.) the ignitor will stay on, and the pilot
valve will remain open until it does sense flame, or until the
call for heat is satisfied. THE SYSTEM WILL NOT LOCK
OUT under this condition.
Assuming that the pilot does light, and flame is sensed, (nor-
mal operation) the ignition system control will turn the ignitor
off, while energizing the main valve. This will allow the pilot
to light the main burner. It will also energize the electronic fan
timer output (causing the conditioned air blower to start after
the fixed 60 second “ON” delay).