MACH® Series
Gas-Fired Boiler
35
9. Perform combustion analysis and readjust as necessary according to table 3-1 and section 3.10.4. It is
recommended that a copy of this report is filed for future reference.
10. Perform a leak test of the gas valves in accordance with the manufacturer's instructions.
11. Test pressure safety relief valve.
Installation and service must be performed by a qualified installer or service agency that has been trained on the
Patterson-Kelley MACH
®
boiler.
5.2 C
LEANING THE
B
URNER
1. Lockout/tagout gas supply to the boiler.
2. Lockout/tagout electrical power to the boiler.
3. Open the front and side doors of the boiler.
4. Locate the blower and burner transition pieces that are directly in the front of the boiler. See 6.2.4 for illustration of
components.
5. Remove the 8 nuts & 2 bolts connecting the blower transition piece to the burner transition piece. The blower
transition piece is supported and remains in place.
6. Remove the 4 nuts holding the burner transition piece to the studs on the front of the boiler.
7. Pull out the burner transition piece with the 2 gaskets and set aside. Inspect the gaskets and replace if damaged.
8. Carefully remove the burner. Rinse the burner with water. Soap may be used, if needed. Rinse thoroughly.
9. Reassemble being sure to install all gaskets and seals properly.
5.3 R
EMOVING THE
H
EAT
E
XCHANGER
Heat Exchanger is heavy and may cause injury if improperly handled. Removal of the
heat exchanger should be performed only by knowledgeable and experienced personnel.
5.4 A
FTER
A
LL
R
EPAIRS OR
M
AINTENANCE
1.
Follow "Pre-Start Check List" (Section 3.8) and all "Safety Checks" (Section 3.9).
2. Check gas pressure. (Section 3.11.2.1). Ensure proper operation of unit
3. Perform combustion check. Adjust gas flow if necessary. (Section 3.11.2..2).
5.5 S
EQUENCE OF
O
PERATION
1. When the Boiler On/Off switch is turned on, power is provided through a circuit breaker to the boiler control and
the combustion blower.
2. If the high gas, low gas or low water level control is open, the boiler control locks out and displays an error.
3. When the water temperature is below the boiler control setpoint minus the hysteresis (On Differential), a heat
request is generated.
4. Provided all limits are made, the boiler will attempt to start.
5. The controller checks that the air pressure switch is open indicating no airflow. The blower is driven towards the
prestart fan speed. When the air pressure switch closes, the 25 second pre-purge time is started. After the pre-
purge, the blower is driven to the ignition speed.
6. A trial for ignition begins. The sequence of events is illustrated graphically below.
7. After ignition, the fan may be driven to low fire before the boiler is released to modulation.
