Pressure Washing Siamese Kit

Siamese Kit for Pressure Washers – Double Your GPM Output

Double the Power. Double the Flow. Combine two pressure washers into one high-output machine with the Siamese Kit from Overkill. This heavy-duty kit lets you merge the output of any two compatible gas or electric pressure washers to double your gallons per minute (GPM) — instantly boosting your cleaning speed and productivity.

Real-World Examples:

• (2) 2.0 GPM machines → 4.0 GPM combined
• (2) 4.0 GPM machines → 8.0 GPM combined
• (2) 5.5 GPM machines → 11.0 GPM combined

You can even pair machines with different GPM ratings (e.g., a 4.0 GPM with a 5.5 GPM) as long as both are set to the exact same PSI.

Why You'll Love the Siamese Kit

• Dramatically increases cleaning speed on large jobs, fleet washing, roof cleaning, soft washing, or heavy-duty commercial work
• Maximizes the capability of the machines you already own
• Simple, robust design built for daily professional use
• Saves time and fuel by running two pumps at full efficiency through one wand/gun setup

Critical Compatibility & Setup Requirements

For safe and reliable operation, your setup must meet these conditions:

• Both machines must be adjusted to the exact same pressure (measured with a gauge directly at the unloader/pump outlet — not after sections of hose)
• Unloaders must be mounted directly to the pump (no hose between pump outlet and unloader block). If your machines have a remote unloader block, you will need to modify the setup first.
• Only pressure-trapped unloaders are compatible (VRT3, VRT100, Green Spring, Blue Spring, Black Spring, etc.)
• Flow-sensitive unloaders (K7, ZK1, and similar) will not work and can cause damage

Important Safety Note: Failure to follow these requirements can cause severe damage to your pump internals. Always verify your setup before use.

By purchasing this kit, you acknowledge and accept full responsibility for proper installation, setup, and operation. Overkill does not guarantee compatibility or performance with every possible pressure washer configuration. While combining machines carries added risks, the massive increase in efficiency and capability typically far outweighs them for experienced users.

What's Included

• High-quality stainless steel check valves for added protection
• Heavy-duty stainless fittings
• 2 Wire hydraulic hose for durability and reliability.
• Stainless Wye fitting for less restrictions vs. a tee fitting.

How is this different from other siamese kits?

• 3/8" Female QC to attach to your units, then 1/2" hose and fittings the rest of the way. No loss of flow or volume!
• High quality 2 wire hydraulic hose is safe, reliable and not prone to shock failure.
• You can use both of your machines individually or at the same time. No need to alter your setup.
• 1/2" Check valves to give your machines more of a saftey.
• Stainless Wye fitting gives more direct flow versus a typical tee fitting.

Ready to turn your two pressure washers into a serious high-flow cleaning rig? Add the Siamese Kit to your cart and experience double the GPM power.

Pro Tip: Always start each machine individually at idle RPM before increasing both machines to full power. When it's time to turn off machines, lower the RPMs to ensure the longest life possible. Remain on the trigger / prevent closing the ball valve as much as possible.

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