What to do when water sprays out of the pressure relief valve on your Campbell Hausfeld gas pressure washer
If the pressure washer runs for more than 5 minutes when the spray wand isn't in use, the water in the pump often overheats, causing the thermal relief valve to open and discharge hot water onto the ground. When the thermal relief valve opens, cool water enters the pump and cools the system. Once the pump has cooled, the thermal relief valve closes and the pressure washer operates normally. If the pressure relief valve purges constantly and doesn't close properly, replace it.
What causes a Campbell Hausfeld gas pressure washer to spray too hard
A failed unloader valve can cause high pressure at the nozzle. The unloader valve recirculates water to the pump inlet when the pump is running but the spray wand isn't in use. If the unloader valve sticks shut, outlet water pressure builds up until you trigger the spray wand or the pressure relief valve trips to release excess pressure. Replace the unloader valve if excessive pressure builds when the spray wand isn't in use.
Some pressure washers have a pressure regulator that limits the water pressure. A defective pressure regulator can cause high pressure at the nozzle. Replace the pressure regulator if it doesn't regulate outlet water pressure properly.