How do I light the pilot on the TC250RNG heater?

Open the natural gas supply valve slowly, allow several minutes to purge air with the automatic control valve button depressed, replace the pilot orifice, and adjust the ignitor electrode gap to .120". Check the wire lead for damage and replace the piezo ignitor and/or ignitor electrode as necessary.

Why does the pilot light go out when the automatic control valve button is released?

Possible causes include not enough warm-up time, low gas pressure, a loose or faulty thermocouple, or a faulty automatic control valve. Follow the listed remedies to address each possible cause.

What should I do if soot is forming inside the heater and the flame is yellow?

Adjust the main burner valve slowly toward the ON position until the flame has a more blue color. If soot is still forming, consult the natural gas supplier for advice.

Troubleshooting, Symptom, Possible Cause, Remedy

MODEL TC250RNG

NATURAL GAS CONSTRUCTION HEATER

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.

SYMPTOM

POSSIBLE CAUSE

REMEDY

Pilot fails to light.	1.	Natural gas supply valve closed.
	2.	Air in gas line.
	3.	Blockage in pilot orifice.
	4.	Piezo ignition system not sparking.

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.

Pilot lights but goes out when automatic control valve button is released.

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.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.

Maximum burn rate is low.	1.	Main burner valve not fully open.	1.	Fully open main burner valve by turn-
				ing the valve handle towards ON posi-
				tion until it stops.
	2.	Plugged gas orifices.	2.	Replace gas orifice.
	3.	Low gas pressure.	3.	Check gas supply; check regulator out-
				put.
	4.	Low fuel supply.	4.	Consult natural gas supplier.

Soot forming inside heater, flame 100%	1.	Main burner valve not open enough.	1.	Adjust amin burner valve slowly toward
yellow.				ON postition until flame has more blue
				color.
	2.	Low fuel supply	2.	Consult natural gas supplier.

Burn rate too high. Flames coming out of 1.	Pressure too high.
emitter.
2.	Unit connected to LP.

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.

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Desa TC250RNG owner manual Troubleshooting, Symptom, Possible Cause, Remedy

Models: TC250RNG