Page 20 | LAARS HEATING SYSTEMS |
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Lower the front of the burner (to avoid damaging pilot shield) then remove the burner tray.
Caution
Black carbon or green soot on a dirty heat exchanger can, under certain conditions, be ignited by a random spark or open flame. To prevent this unlikely occurrence, dampen the soot deposits with wet brush or fine water spray before servicing or cleaning the heat exchanger.
With a wire brush, remove soot and loose scale from heat exchanger. Clean fallen debris from bottom of heater. Make sure burner ports are clear and pilot assembly is free of debris.
d.Reassemble in reverse order:
Be sure the heat exchanger baffles are replaced.
8.The gas and electric controls installed on heaters are engineered for both dependable operation and long life, but the safety of this equipment completely depends on their proper functioning. It is strongly recommended that the basic items be checked by a competent serviceman every year and replaced when necessary. The basic controls are:
a.Water temperature controls.
b.Pilot safety system.
c.Automatic electric gas valve(s).
d.Flow sensing safety device.
9.Low water cutoffs should be inspected every six
(6) months, including flushing of float types.
NOTE: Warranty does not cover any damage caused by lack of required maintenance or improper operating practices.
10.Both modulating and stage valve are adjusted at the factory for minimum permissible rates and should not be readjusted.
SECTION 5.
Troubleshooting and Analysis of
Service Problems
1.For proper service and problem diagnosis of the heater and heater system, the following tools are required:
a.Gas pressure test kit with range from zero to 14 W.C. Either a slack tub manometer or an accurate gas pressure gauge is acceptable with proper adapters which will connect to the available fittings in the line and on the gas valve.
b.
0 to 500 volts A.C.
0 to 1000 ohms continuity.
c.Tube cleaning kit consisting of reamer, stainless steel brush, speed handle and handle extensions.
d.Heater thermometer (with 1/2" NPT well)
2.In addition, the heater should be equipped with a system pressure gauge with proper ranges for heater operation.
I. HEATER WILL NOT FIRE.
Possible Cause | What To Do |
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A. Electric power is off | A. Check to see that main power |
| switch is “ON.” Use testing |
| device to trace power to |
| heater junction box. |
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B. Operating or safety control | B. Turn off power. Use continuity |
has opened circuit to electric | across terminals of each |
gas valve. | operating and safety control |
| switch up to the electric gas |
| valve. Replace effective |
| control. |
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C. Pilot flame is out. | C. Relight pilot per instruction. |
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D. Manual reset device has | D. Follow instructions for start- |
tripped. | up. Reset Pilot safety and all |
| manual reset safety switches |
| and reset manual safety gas |
| valve. |
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E. No gas pressure to burners. | E. Trace gas line to service |
| shutoff cock. If service cock is |
| open, trace gas line to meter. |
| If no pressure is present at |
| meter, call for public utility |
| service. If gas is present in |
| heater inlet, check pressures |
| in following sequence: |
| (1) downstream from pressure |
| regulator. (2) downstream |
| from electric gas valve. |
| Replace or adjust as |
| necessary. |
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F. Electric gas valve operator is | F. Disconnect wiring harness at |
burned out or shortened. | gas valve terminals. Check |
| continuity to actuator coil. If |
| open circuit or short is |
| indicated, replace coil or |
| operator. |
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