Midco G69B - Manual (Page 7)

20
350
550
730
1150
1100
1730
2100
2500
2500
-7-
CAUTION: Do not exceed maximum rated capacity
of burner model - See Tables 1 and 2.
Capacities shown are for total pressure drop of .3"W.C. For
higher permissible pressure drops consult your fuel
supplier.
Source: Gas Engineers HandbookÑ1974
TABLE 3 Schedule 40 Pipe Capacity Chart
Before gas is introduced to the system, a check must be
made to see that there are no open fittings and to make
sure the burner main and pilot manual valves are closed.
After checking above, purge the gas line up to the burner
inlet. Purging the air from the gas supply line at this step
will expedite the first light-off.
CAUTION: Purge outside the building. Do not
purge into the gas utilization equipment combustion
chamber.
Gas Supply
Pipe Size
N.P.T.
1"
1-1Ъ4"
1-1Ъ2"
2"
2 -1Ъ2"
3"
Type of
Gas
Natural
Propane
Natural
Propane
Natural
Propane
Natural
Propane
Natural
Propane
Natural
Propane
APPROXIMATE CAPACITY-MBH
Length of Pipe Ñ Feet
40
385
500
785
760
1200
1450
2280
2300
2500
2500
60
300
400
630
610
960
1150
1800
1850
2500
2500
100
300
480
460
725
870
1370
1400
2200
2500
2500
200
330
320
500
610
960
980
1550
1700
2500
MAIN REGULATOR
MAIN REGULATOR
VENT
PILOT MANUAL
VALVE
BALL
VALVE
PILOT
REGULATOR
BLOWER
MOTOR
MANUAL MOTOR RESET
BUTTON
(MAY HAVE AUTO RESET)
MANIFOLD PRESSURE
TAP
DRIP LEG
REDUNDANT MAIN
AUTOMATIC VALVES
BF INPUT ADJUSTER
(HIDDEN)
BALL VALVE
PILOT SOLENOID
VALVE
PILOT MIXING
TEE
PILOT
PRESSURE TAP
PEEP SIGHT
PILOT AIR
TUBE
RESET
BUTTON
BLOWER
AIR
SWITCH
FLAME SAFEGUARD
CONTROL INLET PRESSURE TAP
1/4 TEE
1/4 PLUG
FIGURE 11 Piping Connections
VII INITIAL START-UP
WARNING: Repeated unsuccessful attempts to
light may result in accumulated gases in gas
utilization equipment and chimney. To prevent these
gases from reaching an explosive level, periodically
purge the gas utilization equipment.
CAUTION: All cover plates, guards, and
enclosures must be maintained in place at all times
except during maintenance and servicing.
CAUTION: Optional equipment and/or special
limit controls such as high/low gas pressure switches
can alter the start-up procedure. See Section XIV-
SPECIAL EQUIPMENT.
1.
Check the piping for leaks. A quick way to do this is to
close the main manual shut-off valve and manual
pilot valve, then turn on the gas pressure to the gas
supply line and observe the meter test dial. There
should be no movement of the test dial hand for at
least twenty minutes. All other gas appliances must be
completely shut off during this test (including pilots). If
a leak is detected it should be located with a soap
suds test. Test the main automatic valve for tightness.
(see Section XII for instructions). The ball valve is
intended to be open at all times except when testing
for main valve leakage. The Main Manual Shut-Off
Valve must be used for manual gas shut-off.
2. Make sure that the burner main and pilot gas lines are
completely purged of air. Do not purge into the
combustion chamber. Purge outside the building.
3. Make sure the burner power switch is off, manual
valve is closed, pilot manual valve is closed,
motor is free to rotate, and flame safeguard reset
button is set.
4. Make the proper settings on all limit controls and set
controller to call for heat.
5. Set blower air shutter wide open.