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START-UP PROCEDURES
B. CONTROL DESCRIPTIONS
See Figure 6.1 in Section 6 (Electrical) for locations of
these devices.
1. FLAME ROLL-OUT SAFETY SHUT-OFF SWITCH
(FLAME ROLL-OUT SWITCH) – A thermally
activated switch located between the first burner from
the left and the manifold bracket. The flame roll-out
safety shut-off switch will sense excessive temperature
caused by continued flame roll-out and shut down
main burner gas. This is a non-recycling switch that
must be replaced once it has been activated and the
cause of the roll-out eliminated.
2. DIFFERENTIAL PRESSURE SWITCH – This device
senses a negative or suction pressure in the blower
housing and air box when the blower is energized. If
there is not excessive blockage in the venting system
or air inlet vent the switch will close, allowing power
to energize the ignition system.
3. LIMIT – A thermally activated, manually adjustable
switch located on the right side of the boiler. The
temperature sensing element is placed in the supply
and will shut down main burner gas if the supply
water exceeds the preset temperature limit. This is a
recycling switch that will automatically reset when the
supply water falls below the preset temperature.
4. LOW WATER CUT-OFF (FOR GRAVITY SYSTEMS
OR HOT WATER BOILERS INSTALLED ABOVE
RADIATION LEVEL) – A level-sensing device (float or
probe) located in supply piping near the boiler. If
water level in the system drops below the control's
position, it will shut down main burner gas. The
control will automatically reset once the water level
rises above its position.
C. ADJUSTMENT OF GAS PRESSURE
REGULATOR
1. Move the manometer to either the outlet pressure tap
on the gas valve or to the burner manifold test tap.
Set manifold pressure as follows for various gases.
a. Natural Gas . . .3.5" Water Column (0.9 kPa)
b. LP Gas . . . . . .10.0" Water Column (2.5 kPa)
2. To adjust gas pressure, turn adjusting screw of gas
pressure regulator counterclockwise to decrease
pressure, clockwise to increase pressure. Refer to
Figure 7.2 for location of gas pressure regulator.
Replace the cap screw when adjustment is complete.
3. In no case should the final manifold pressure vary
more than ±0.3 inches water column (0.07 kPa) from
the above specified pressures. Any necessary major
changes in the flow should be made by changing the
size of the burner orifice spuds.
4. When adjustment is complete, turn off boiler, gas flow
and electricity to boiler. Remove manometer and plug
tapping with plug provided. Turn utilities back on and
resume checkout.
22
D. CHECKING BURNER INPUT
1. Refer to rating label mounted on the jacket top panel
to obtain the rated BTU per hour input. In no case
shall the input to the boiler exceed the value shown
on the rating label.
2. Check input by use of the following formula
(PB Heat suggests reading meter for 2 Cu.Ft. [0.0566
cubic meter]):
U.S. Customary Units:
Input (BTU/Hr.)= 3600 x F x H
Where:
3600 – Seconds per hour
F – Cubic Feet of Gas Registered on Meter
H – Heat Value of Gas in BTU/Cubic Feet
T – Time in Seconds the Meter is Read
SI Metric Units
Input (kW)= 3600 x F x H
Where:
3600 – Seconds per hour
3.6 – Megajoule (MJ) per kilowatt hour (kWhr)
F – Cubic Meters of Gas Registered on Meter
H – Heating Value of Gas in MJ/Cubic Meter
T – Time in Seconds the Meter is Read
3. As an alternative, use Table 7.1a and 7.1b. Use the
heating value provided by gas supplier. Use a
stopwatch to record the time it takes for 2 cubic feet
(0.0566 cubic meter) of gas to pass through the meter.
Read across and down to determine rate.
E. CHECK-OUT PROCEDURE
1. After starting the boiler, be certain all controls are
working properly. Check to be sure that the limit will
shut off the boiler in the event of excessive water
temperature. This can be done by lowering the limit
setting until the main burners shut down. When
proper limit function is confirmed, return the dial to its
previous setting.
2. To check operation of the ignition system safety
shut-off features:
a. Turn gas supply off.
b. Set thermostat or controller above room
temperature to call for heat. Watch for igniter glow
at pilot burner.
c. Igniter will continue to glow for 30 seconds, de-
energize for 30 seconds, then re-energize and glow
for another 30 seconds. It will then de-energize for
5 minutes before restarting the sequence.
d. Turn gas supply on.
e. Reset the boiler and control by following
Operating Instructions.
f. Observe boiler operation through one complete
cycle.
T
T x 3.6
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