Get The App From Play Store!

Skip to main content

BLACK FRIDAY EVENT use code BF25 at checkout to SAVE 25% when you spend £30 or more excluding delivery.

BLACK FRIDAY EVENT use code BF25 at checkout to SAVE 25% when you spend £30 or more excluding delivery.

Karcher 411A pressure pulsing when spraying ?

Karcher 411A pressure pulsing when spraying ? When im using the pressure washer it pulses when i depress the trigger. Its not pulsing when the trigger is not depressed. Ive removed the case and watched it run. There is a pressure switch that cuts the power to the motor when the trigger isnt pressed to stop the pump destroying its self. This mechanical pressure switch is pulsing in and out as is the pressure is getting too high for the machine. So, im looking for any advise on why this pressure switch should pulse when the trigger is pressed. If i hold the switch forward with a screwdriver it runs fine! Can anyone help please!

By Tim - POntefract - 13 September 2010

Answer this Question (2 Answers)

  • There is a small non-return valve in the outlet connection, underneath the small triangle shaped block in the pump head, the valveis white nylon with a small O ring on the end and a light spring that holds it closed, if this valve passes it will allow the pressure switch to hunt off and on. A repair can be achieved by replacing this small valve head. By Anonymous - UK - 15 June 2013
  • Replace the pressure washer control head and the pressure washer cylinder head . normally fixes the prob. By G man - - 14 March 2011

Submit your answer

A confirmation email will be sent to this address. Your email address will not be published.

Contact Permission:

I am happy to receive vouchers, deals, exclusive offers and updates from eSpares by email and I acknowledge that my details could be shared with trusted third parties. We'll always treat your personal details with the utmost care and will never sell them to other companies for marketing purposes.

Please let us know your preference by selecting one of the options below?

Pressure Washer Control Head Parts Set Stock Number: ES538412

Genuine spare part for select Karcher pressure washers

Q&A tips & guidelines

  • Focus on the features or function of the product

  • Write your question in clear English

  • Be polite! Profanity won't be approved

  • Don't include personal info

  • Don't name other websites

  • Don't mention product prices