Troubleshooting

Disconnect the machine from the power source before making any repair.

Symptom	Cause	Solution

Motor will not start	On/Off switch is in the “OFF” (O)	Turn switch to the “ON” (I) position
	position.

	Power cord is not plugged in.	Plug in power cord.

	Extension cord is too long.	Replace extension cord with either
	Extension cord is not proper gauge.	“a 25 ft. 12/3 gauge cord or a 50
	Extension cord is damaged.	ft. 10/3 gauge cord.

	Electrical outlet does not supply	Try a different outlet.
	adequate power.

	Tripped circuit breaker	Reset breaker (power supply) or
		ground fault circuit interrupter.

Unit does not reach high	Diameter of garden hose is too	Replace with a 3/4 inch garden
pressure.	small.	hose.

		Check garden hose for kinks, leaks
	Water supply is restricted.	and blockage.

	Not enough inlet water supply.	Open water source full force.

	Water inlet filter is clogged.	Remove filter and rinse out in
		warm water.

	Spray wand is in low pressure	Turn spray wand to high pressure
	position.	position.

Output pressure varies high	Not enough inlet water supply.	Turn water on full force. Check
and low.		garden hose for kinks, leaks or
		blockage.

	Pump is sucking air.	Check that hoses and fittings are
		air tight. Turn off machine and
		purge pump by squeezing trigger
		gun until “a steady flow of water
		emerges through the nozzle.

	Water inlet filter is clogged.	Remove filter and rinse out in
		warm water.

	Discharge nozzle is obstructed.	Blow out or remove debris with a
		“fine needle.

	Calcified gun, hose or spray wand.	Run distilled vinegar through
		“detergent suction tube.

K 3.78 specifications

The Kärcher K 3.78 is a versatile and powerful pressure washer designed for light to medium-duty outdoor cleaning tasks. Renowned for its combination of performance and user-friendliness, it has become a popular choice among homeowners looking to maintain the cleanliness of their vehicles, patios, driveways, and garden furniture.

At the heart of the K 3.78 is its robust motor, which delivers a maximum pressure of 1800 PSI, allowing users to efficiently tackle various grime and dirt challenges. The water flow rate of up to 1.6 GPM ensures that stubborn stains and dirt are effectively washed away, making it suitable for a wide range of applications.

One of the standout features of the K 3.78 is its innovative N-Cor pump, which is designed for durability and longevity. It is resistant to corrosion, ensuring that the pressure washer stands the test of time even with regular use. The K 3.78 also includes a detergent injection system, enabling users to apply cleaning solutions directly through the spray wand, enhancing cleaning efficiency for more challenging stains.

The pressure washer is equipped with a 20-foot high-pressure hose, giving users ample reach while staying mobile. The ergonomic handle and lightweight design further ensure comfort during use, reducing hand fatigue, especially during extended cleaning sessions. Additionally, the integrated on-board storage allows for convenient access and storage of accessories, including nozzles and the detergent bottle.

Speaking of nozzles, the K 3.78 features an adjustable spray wand with multiple settings. This versatility allows users to switch between high-pressure jets for tackling tough dirt and wider spray patterns for rinsing larger areas, all without the need to change out the nozzle.

When it comes to safety, the K 3.78 includes a safety lock mechanism on the trigger gun, preventing accidental activation. The robust construction of the unit ensures stability during operation, reducing the risk of tipping over.

In summary, the Kärcher K 3.78 is an excellent investment for those seeking a reliable pressure washer that balances power and convenience. With its durable construction, versatile cleaning capabilities, and user-friendly design, the K 3.78 makes outdoor cleaning tasks simpler and more efficient, keeping your spaces looking pristine all year round.