14
On a call for heat:
The thermostat will actuate, completing the circuit be-
1.
tween terminals T and T.
The R8222C relay coil will energize thus pulling in the
2.
relay contacts.
The circulator starts and power is switched to the limit. If
3.
limit circuit is closed the venter motor and TR-2 trans-
former are energized.
The venter motor starts and develops static pressure.
4.
When the static pressure is reached the pressure switch
5.
pulls in completing the circuit between TR-2 and the
SV9501H gas valve system.
The SV9501H opens the pilot valve and ignites pilot. After
6.
pilot is proven the main burner will ignite.
In the event the boiler water temperature exceeds the high
7.
limit setting the power will be interrupted to the venter
motor, and TR-2, thus interrupting power to the ignition
OPERATING INSTRUCTIONS
STOP! Read the safety information in the user’s informa-
1.
tion manual.
Set thermostat to lowest setting.
2.
Turn off all electric power to the appliance.
3.
This appliance is equipped with an ignition device which
4.
automatically lights the pilot. DO NOT try to light the
pilot by hand.
Move the ignition system control switch to the "OFF"
5.
position. See figure #10.
Wait five (5) minutes to clear out any gas. If you then
6.
smell gas, STOP. Follow step 2 in the lighting procedure
previous page, "What To Do If You Smell Gas." If you
don't smell gas, go to the next step.
Move the ignition system control switch to the "ON" posi-
7.
tion. See figure #10 above.
Turn on all electric power to the appliance.
8.
Set thermostat to desired setting.
9.
If the appliance will not operate, follow the instructions
10.
"To Turn Off Gas To Appliance" (Below) and call a quali-
fied service technician or your gas supplier.
SEQUENCE OF OPERATION
system. Power will remain off until the water temperature
drops below the high limit setting. The circulator will con-
tinue to operate under this condition until the thermostat
is satisfied.
Should the air flow (static pressure) be interrupted (ie.
8.
blocked flue), the pressure switch will sense a drop in
pressure, opening the circuit between the ignition system
and TR-2. The venter motor will continue to operate until
static pressure is reached or thermostat is satisfied.
In the event the flow of combustion products through the
9.
boiler flueways becomes reduced or blocked, the Q34505
pilot will lose flame rectification and shut off the main
burners. The boiler will try for ignition but will not light.
If this condition occurs, turn off the main power and do
not put the unit into operation.
When the thermostat is satisfied power is interrupted to
10.
the relay coil and the relay drops out cutting power to the
circulator, venter motor, and TR-2.
ON
OFF
GAS
GAS
PRESSURE REGULATOR
ADJUSTMENT BENEATH
COVER SCREW
PILOT FLOW ADJ.
SCREW BENEATH
C
ONTR
OL
IGNITER
IGNITION SYSTEM
COVER SCREW
CONTROL SWITCH
PRESSURE
TAP
OUTLET
INLET
TO TURN OFF GAS TO APPLIANCE
Set thermostat to lowest setting.
1.
Turn off all electric power to the appliance if service is to
2.
be performed.
Move the ignition system control switch to the "OFF"
3.
position. DO NOT FORCE
LIGHTING INSTRUCTIONS
Figure 10
National Excelsior Company
www.excelsiorhvac.com
Subject to change without notice.
