Graco Probler P2 Review: Mix Chambers, Side Seals and Daily Care

The Probler P2 has been a staple in polyurea and spray foam rigs for a long time, and it earned that spot by being tough and simple. This is our ArmorThane Tech Team review: verified specs, the mix chamber lineup, the wear parts that matter, and the routine that keeps it spraying.

Our take in brief

• Strengths: Graco rates its double-piston design at more than 300 lb of triggering force, which helps it shear through buildup. Its anti-crossover design keeps material out of the air piston. The mix chamber insert is easy to replace.
• Trade-offs: At 3.9 lb it is heavier than lighter air-purge guns, and it rewards careful daily maintenance. Skip the routine and side seals and screens become your problem.
• Best for: Production polyurea, coatings and foam applicators who want a rugged, rebuildable gun.

Probler P2 specs

Sources: Graco Probler P2 manual 313213, Probler P2 Elite manual 313266 and the Probler P2 product page.

Mix chamber modules: AA, 00, 01, 02 and 03

The P2 changes output and pattern by swapping the mix chamber module. Each module has a matching replaceable insert. Graco's manual lists these sizes:

Graco also lists 04 (GC2504, 0.100 in insert) and 05 (GC2505, 0.125 in insert) modules for higher output. Smaller sizes like AA and 00 suit lower output machines and detail work; 02 and 03 suit high output production. Match the module to your proportioner's output at your spray pressure.

Side seals and check valves

Side seals ride against the mix chamber and keep A and B apart until impingement. Graco's standard is the stainless steel GC2498, and we sell it in a side seal kit. An acetal seal (GC2494) is also available. Inspect seals daily for scratches, buildup or foreign material; a scored seal lets material cross over and causes pressure imbalance.

Behind the side blocks, the check valve and filter assemblies protect the gun from debris and backflow. Key parts from Graco's parts list:

• 16P010 check valve filter, two per gun (GC1904 on the P2 Elite)
• GC0259 1/4 in stainless check ball
• GC1922 and GC1923 check valve springs
• GC2496 40 mesh filter screen (Graco also lists a 100 mesh option)

Daily maintenance routine

1. Inspect side block seals and clean or replace as needed.
2. Remove and clean or replace the filter screens.
3. Clean the gun exterior with a brush and compatible solvent.
4. At shutdown, relieve pressure and engage the piston safety lock.
5. Inject one full pump of white lithium grease into the zerk until grease appears at the insert tip. Two shots maximum.
6. Shut off the air purge and soak the spray tip in solvent.

Common problems

From Graco's troubleshooting table, the usual suspects are: a gun that will not actuate (safety lock engaged), no spray (closed material valves or plugged impingement ports), slow actuation (damaged piston O-rings or a dirty air switch), loss of round pattern (dirty insert), and pressure imbalance (plugged ports or a viscosity mismatch). Our Troubleshooter walks you through these checks step by step and gives the exact part numbers.

What we stock for the Probler P2

We carry the complete Probler P2 gun (GUN130), all the modules and inserts listed above, the GC2498 side seal kit and acetal seal, the O-ring kit, check valve filters, balls, springs and screens, air pistons, air switch parts, triggers and the matched drill kits. Find them in Parts & Rebuild Kits, or open the Gun Parts Finder and tap any part on the Probler P2 exploded diagram. Approved applicators see account pricing automatically through the Applicator Program.