What is Bypass in a Pressure Washer

When operating a high-pressure washer, the machine enters a "bypass" mode whenever the spray gun is closed. The bypass is a separate, closed circuit within the pump head where water is continuously circulated at a residual pressure of approximately 10 bar. This mechanism allows the machine to remain pressurized and ready for immediate use once the gun is reopened.

Without a bypass system, closing the gun would cause pressure to build up inside the pump head to dangerous levels, potentially leading to equipment failure. The bypass ensures safe operation by allowing brief pauses between spraying without damaging the machine. All Kränzle high-pressure washers are equipped with a bypass system for enhanced durability and performance.

Risks of Running a Pressure Washer in Bypass Too Long

Although the bypass system is essential for safe operation, running a pressure washer in bypass for extended periods can cause significant damage. Since the water circulates within a closed loop, friction increases the temperature inside the pump head, leading to two major risks:

1. Damage to the Seals

The seals inside the pump head are designed to withstand temperatures up to 60°C. When the temperature exceeds this threshold, the seals may become compromised, resulting in:

• - External leaks – Water visibly leaking from the pump head.

• - Contaminated oil – Water may seep into the oil, causing it to turn milky in appearance, which affects lubrication and overall performance.

Kränzle’s Solution

To counteract this issue, Kränzle incorporates a leakage return system into its high-pressure washers. The plungers in the pump feature a double-seal design with a return channel between them. Any water that passes the first seal is immediately drained away, preventing it from reaching the oil sump and protecting the internal components from water damage.

2. Plunger Bursting

Another critical risk of prolonged bypass operation is the potential for plunger failure, which is particularly common in pressure washers using fully ceramic plungers. When exposed to extreme heat, ceramic plungers may crack or burst due to thermal shock, leading to costly repairs and downtime.

Kränzle’s Solution

Kränzle high-pressure washers are equipped with stainless steel plungers with a double ceramic coating. This innovative design allows for superior heat conduction to the oil sump, reducing the risk of overheating. Additionally, these plungers offer exceptional durability and wear resistance, ensuring a longer lifespan and improved performance over time.

Total Stop: An Additional Safety Feature

To further protect the machine from the risks associated with prolonged bypass operation, Kränzle integrates a Total-Stop (TS) system into its high-pressure washers. This feature ensures that as soon as the washer enters bypass mode, the motor automatically shuts off either immediately or after a short delay. When the gun is reopened, the motor restarts seamlessly.

The Total-Stop system provides several advantages:

• - Prevents pump overheating – Reduces strain on the pump head and internal components.
• - Extends equipment lifespan – Protects both the pump and drive mechanism.
• - Enhances energy efficiency – Minimizes unnecessary power consumption.