6
104133
NATURAL GAS CONSTRUCTION HEATER
MODEL TC250RNG
SYMPTOM
Pilot fails to light.
Pilot lights but goes out when automatic
control valve button is released.
Maximum burn rate is low.
Soot forming inside heater, flame 100%
yellow.
Burn rate too high. Flames coming out of
emitter.
POSSIBLE CAUSE
1. Natural gas supply valve closed.
2. Air in gas line.
3. Blockage in pilot orifice.
4. Piezo ignition system not sparking.
1. Not enough warm-up time.
2. Low gas pressure.
3. Thermocouple loose or needs to be re-
placed.
4. Automatic control valve needs to be re-
placed.
1. Main burner valve not fully open.
2. Plugged gas orifices.
3. Low gas pressure.
4. Low fuel supply.
1. Main burner valve not open enough.
2. Low fuel supply
1. Pressure too high.
2. Unit connected to LP.
REMEDY
1. Open natural gas supply valve slowly.
2. Allow several minutes to purge air with
automatic control valve button de-
pressed.
3. Replace pilot orifice.
4. Adjust ignitor electrode gap to .120".
Check wire lead for damage. Replace
piezo ignitor and/or ignitor electrode as
necessary.
1. Relight, hold automatic control valve
button in 45 seconds.
2. Check for proper gas supply.
3. Tighten connection or replace thermo-
couple.
4. Replace automatic control valve.
1. Fully open main burner valve by turn-
ing the valve handle towards ON posi-
tion until it stops.
2. Replace gas orifice.
3. Check gas supply; check regulator out-
put.
4. Consult natural gas supplier.
1. Adjust amin burner valve slowly toward
ON postition until flame has more blue
color.
2. Consult natural gas supplier.
1. Check inlet pressure. If over 4 psi ad-
just or install regulator.
2. Verify gas source. If connected to LP gas,
disconnect. Connect to natural gas.
TROUBLESHOOTING
You may have further questions about this
heater. If so, contact DESA International’s
Technical Service Department at 1-800-
323-5190.
WARNING: Never attempt to service heater while it is connected
to natural gas supply, operating, or hot. Severe burns can occur.
