Table 4. Trouble Shooting Chart
Below in chart form are various symptoms of a malfunctioning system, possible defects that will cause these symptoms and suggested corrective measures. The chart assumes that the proper gas pressure is available to the heater and that the lighting procedure is as stated on the plate attached to the heater.
SYMPTOMS | CAUSES | SOLUTIONS |
|
|
|
burner light off very slow | partially block pilot orifice | replace |
| pilot out of adjustment | |
|
|
|
burner light off very slow | partially blocked burner orifice | replace |
color stays dull |
|
|
|
|
|
burner flash back | low gas pressure | correct line pressure |
(roaring noise during operation |
| or call your gas supplier |
and ceramic grid surface will be |
|
|
dark) | damaged burner | replace |
|
|
|
ceramic grid or burner sooting up | first check for damaged burner | replace if damaged |
(when new or after cleaning) | orifice |
|
| if burner orifice is not damaged | replace |
| then check for damaged manifold |
|
|
|
|
pilot cannot be ignited | blocked pilot orifice | replace |
| gas cock not in position | gas cock knob must be |
|
| turned to pilot and held |
|
| depressed |
| pilot gas flow adjustment | open and adjust |
| screw may be closed | (see Figure 12) |
|
|
|
pilot lights but goes out | defective thermocouple | replace |
| defective control | replace |
|
|
|
pilot stays lit but main burner | loose wire or improperly wired | tighten connections, check |
will not light |
| wiring diagram |
| defective control | replace |
| blocked burner orifice | clean orifice or replace |
|
|
|
failure to ignite | main gas off | open manual valves |
| air in gas line | bleed gas line |
| loose wire connections | tighten wire connections |
| dirty wire connections | clean terminals and secure |
|
| terminals |
|
|
|
3. REPLACING THE GAS VALVE UNIT
A.Remove the two gas valve unit wires at the gas control valve labeled “PP”.
B.Unscrew gas valve from gas piping.
C.Reconnect gas valve and unit wires to terminals “PP”. Be sure to leave thermostat wire on one terminal.
should be checked before shutdown and again before the next use.
Dusty, wet or corrosive environment. Since these environments can cause the gas control to deteriorate more rapidly, the system should be checked more often.
The gas control should be replaced if:
A.It does not perform properly on checkout or trouble shooting.
4. FREQUENCY OF OPERATOR CHECKS | B. The gas control knob Is hard to turn or push down, or |
Intermittent use. Appliances that are used seasonally | it fails to pop back up when released. |
Model # MH25NG/LP | HS25NG/LP | 13 Installation instructions and Owner’s Manual |
