Technical Guide
How to Prime Your Airless Paint Sprayer
Correct priming is the most important step before spraying. Get it wrong and you get air in the system, uneven pressure, and a frustrating first coat. This guide covers all Magnum models A20 through A100.
⚠ Pressure relief first. Before priming or changing anything — always perform the pressure relief procedure. Turn off, unplug, set valve to PRIME, hold gun against metal pail, pull trigger. Always.
Priming procedure — step by step
A100 specific — TSL
The A100 has a throat seal cup that must be filled with TSL (Throat Seal Liquid) before every use. Check the cup before priming — top up if low. This prevents pump rod wear and extends pump life significantly.
Common priming problems
Fluid won't flow from drain tube: Check suction tube is fully submerged. Check inlet screen for blockage — remove and clean if needed (part 187651).
Air bubbles won't clear: Prime longer — up to 2 minutes. Check suction tube for cracks or kinks. Check garden hose washer (part 115099).
Motor cuts out during priming: Pressure set too high. Start at lowest setting. If using a generator, minimum 3500W regulated.
Maximum tip sizes by model
A20/A30 = TRA515 · A45 = TRA517 · A60 = TRA619 · A80/A100 = TRA621. Exceeding these will overload the pump and void warranty.
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