We have had many recent inquiries to our Technical Hot Line regarding troubleshooting of the Carlin nozzle line heater. In order to understand troubleshooting and servicing of the Carlin nozzle line heater you must first understand how it works. The heating element is a solid-state P.T.C. (positive temperature coefficient) heater. The heater is self-regulating to produce more or less heat as needed to maintain between 120 F and 130 F at all times. The heater must be continuously energized to insure the burner is ready to start with a warm nozzle and combustion heat at all times.

Remember: Oil burner nozzles are manufactured and tested using simulated number two (#2) fuel oil at 100 F. As the temperature of #2 fuel oil decreases the viscosity increases. This causes larger oil droplets, increasing the flow rate through the nozzle, resulting in smokier burner operation, the end result of which is soot.




The P.T.C. heater will heat both the oil in the combustion head assembly, as well as the air in the blast tube. The results of warm oil and warm air are:

1. Improved atomization
2. Improved ignition – smaller oil droplets ignite quicker
3. Cleaner boiler or furnace
4. Cleaner burner heads

To test the operation of the P.T.C. heater, disconnect electrical power and take an Ohm’s reading across the two pink wires. The following are the operational readings:

600 – 1500
Normal operating range None
1 – 599
Subnormal readings Replace heater
Dead electrical short Replace heater

The “rule of thumb” quick test:

Remove combustion head, check to see if heater is warm, if it is warm you are all set. If it is not warm, check to see that heater is wired to constant power source. If wired correctly and not warm replace heater.

The wattage drawn on our P.T.C. heater is 13 watts on cold start with a normal draw of 5-7 watts when maintaining temperature. This wattage usage calculates to approximately 5.0 kilowatts per month. On average this translates to about 55¢ per month or $6.60 per year.

If you have any further questions, please give us a call on our Technical Hot Line

Technical Hot Line 1-800-989-2275