Section IV: Troubleshooting
WARNING:
All troubleshooting procedures must be followed completely by competent personnel familiar with
boilers and accessories.
CAUTION:
Read and follow all instructions before troubleshooting any boiler equipment.
A. Normal Operation
All Lattner forced draft gas-fired boilers follow the same
operating sequence:
1. Turn the pump switch ON.
2. McDonnell Miller pump control turns on the pump or
solenoid water valve.
3. Pump or solenoid valve fills boiler.
4. McDonnell Miller shuts off the pump or solenoid
water valve when water is at normal operating level.
5.
Turn boiler switch to the ON position.
6.
Gas valve opens and main burners light.
7.
Boiler pressure will rise to the pressure controller's
set point. The then controller will shut off the gas
valve.
8.
When the boiler calls for water, the McDonnell Miller
level control will turn on the pump or solenoid water
valve.
9.
If the pump cannot fill the boiler, the McDonnell
Miller low water cut-off will shut down the boiler. If
the McDonnell Miller does not shut down the boiler,
the auxiliary low water cut-off will shut down the
boiler.
10.
If the boiler has optional controls, refer to the wiring
diagram.
B. Basic Service Tools
The following basic equipment will aid in troubleshooting
Lattner boilers. Not all equipment is needed for every repair:
1. Schematic diagram of the boiler
2.
Volt/ohm meter
3. Ammeter
4.
Gas pressure gauge
5. Flame simulator
6.
Continuity tester
7.
Flue gas analyzer
8.
Carbon monoxide sampler
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C. Before You Begin
Before you begin any troubleshooting procedures, check the
following:
1. Make sure the pilot is lit.
2. Be certain boiler switch is on and that there are 115
volts supplied to the boiler control circuit.
3.
Be certain pump switch is ON and check for proper
pump voltage and phase if different from boiler
circuit.
4.
Check if breaker is tripped or if fuse is blown.
5.
Make sure there is water in the boiler.
6.
Be certain manual gas cock is open and that gas is
supplied to the boiler.
7.
Be certain that all manual resets have been
pushed.
Note: All Lattner boiler controls are wired in series.
The boiler operating controls and limits form a series
circuit. When all switches close, the boiler should fire.