How to Diagnose Pressure Washer Pump Problems

Over time, pressure washers can suffer from wear and tear and in turn, develop faults. If your pressure washer is showing signs of problems, this article will help you to diagnose and fix the issue so your appliance is back up and running again.

Below, we will help you identify the most common faults with a pressure washer by looking at the three main signs that indicate your appliance requires assistance. These are:

• Leaks
• Pulses
• Low Pressure

Pressure washers can also develop electrical problems too. If your appliance is dead, tripping your fuse or electrics, or is stalling when you use it, take a look at our article on how to diagnose pressure washer electrical problems.

If your pressure washer leaks, pulses when not in use or has low pressure, take a look at the video or follow the guide below to help diagnose and fix the issue.

Before you begin any diagnosis or repair, make sure your appliance is switched off and completely disconnected from the mains.

First, we're going to look at leaks. This is a very common problem with pressure washers and is most likely caused by perished seals or faulty components.

If your leak is coming from the hose, this is usually caused by a worn or perished O-ring seal or gasket which is located at the base of the hose. This can be easily removed and replaced just by simply lifting it off.

If the leak is coming from the case, it is most likely due to a fault with one of three parts. These are the cylinder head or the inlet and outlet elbows.

Sometimes, a leak can be due to water having been left in the pressure washer over winter which freezes, expands and then splits a hose or part. It can be hard to find which part these splits have occurred in. A great way to test this, is to remove the case from the pressure washer, reapply the three water hoses and turn the water on. Make sure the appliance is not plugged in while you do this. The water pressure will then identify which area the leak is occurring in.

If there is a leak in any area of the cylinder head, the pressure that stops the machine from running will quickly disperse, causing the motor to restart or pulse. Try to find where the leak is coming from or replace the cylinder head seals.

Another cause of the motor pulsing is water starvation. This can be down to a blocked filter on the inlet. You can remove and clean this if the pressure washer is pulsing but not leaking.

Another common problem with pressure washers is low pressure. This can be due to the O-rings and seals inside the pistons, here:

Or, to do with the valve on the opposite side here:

So try removing these and clean out any dirt or debris and replace if necessary.

And there you have it, how to diagnose and fix three common pressure washer problems. We hope this has helped you to fix the issue and get your pressure washer back up and running again.

If you're in need of any other replacement parts or accessories for your pressure washer, take a look at the eSpares website. Or to diagnose any other pressure washer problems or faults with other household or garden appliances, take a look at our Advice Centre.