Cold starts become unreliable
A burner operates satisfactorily after it has warmed, but it develops delayed ignition during very cold weather. The oil supply passes through a cold section before reaching the fuel unit. A recently installed nozzle carries the expected nominal flow marking, but its pressure basis and pattern have not been compared with the appliance specification. The service history also lacks a recorded inlet-vacuum reading under the cold-start condition. No assumption has yet been made about a universal air-shutter setting. The technician is holding the equipment out of normal operation while checking for unburned fuel and preparing the approved diagnostic process. Both the burner and appliance identification are available for comparison.
1. Which interacting conditions should be assessed?
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Cold viscosity can affect delivery and atomization, while the nozzle must match all specified characteristics and pressure conditions. Assess supply evidence, approved firing geometry and ignition performance under the relevant cold condition without repeatedly reproducing unsafe ignition.
2. Why is the flow marking alone insufficient?
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The reference pressure, spray pattern and angle affect actual delivery and flame formation. A matching nominal number does not prove that the nozzle and operating pressure reproduce the approved burner-appliance combination.