| Early pressure washers had no trigger and delivered high pressure water as long as the machine was on. The trigger gun was added to increase the safety for the pressure washer. However, since a plunger pump delivers a constant volume of water, an unloader must be used to redirect the water. This water is redirected (or bypassed) back to the inlet of the pump. The water continuously circulates through the pump until the trigger is pulled or the machine is shut off. As the water circulates, it will heat up. A pressure washer should not be left on without the trigger pulled for more than 3-5 minutes.
Hot water pressure washers use diesel, kerosene, propane, or natural gas to continuously heat the water. The water is heated after the water is pressurized, which keeps the pump cool. Hot water pressure washers have a "Heat Rise" of between 130°F and 150°F. The "Heat Rise" is the amount of temperature that a pressure washer can add to the incoming water. This means that pressure washers can have heat outputs of about 180°F to 200°F. As long as water is flowing through the heat chamber, a properly tuned burner system will stay on continuously. However, if the trigger is released, the burner system must be turned off. This is done with a "flow sensing" switch, by turning off power to the fuel solenoid. The "flow sensing" switch can be an actual flow switch, a pressure switch, or a vacuum switch.
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The Difference between a
Hot Water Pressure Washer and a Steam Cleaner.
A hot water pressure washer produces water that is between 1000psi and 5000psi and is approximately 200°F hot. These machines are very good at cleaning dirty and greasy equipment. Since the water is pressurized, it will not turn to steam even above the 212°F "normal" boiling temperature of water.
A steam cleaner produces actual steam. They heat 300psi water to about 300°F and use an expanding cone nozzle. These units are usually only used for applications where either sterilization is required or a super sticky substance needs to be melted off. A steam cleaner is generally more dangerous to use and requires a more skilled operator. Almost all modern day steam cleaners are actually combination units. This means that they can be used as either a Hot Pressure Washer or a Steam Cleaner by changing a few settings and the nozzle.
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Common Pressure Washer Problems.
Below is a list of common pressure washer problems and their most likely causes. This list does not constitute all problems with pressure washers and their solutions. Always take safety precautions such as disconnecting electricity and never blocking a high pressure leak or nozzle with any part of your body.
If your problem is not listed below or you have any further questions, please don't hesitate to contact us.
1-800-287-8306
Email: info@industrial-equipment.biz
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Burner won't come on
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1. Burner Transformer is no longer functioning.
2. Tip is too big and is not creating enough pressure for a pressure switch.
3. Tip is too small or clogged and not allowing enough flow for a flow or vacuum switch.
4. Temperature or flow sensing switch is malfunctioning.
5. Fuel Solenoid is not operational.
6. Pump or Unloader is bypassing water.
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Burner stays on
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1. Pressure switch or Fuel Solenoid failed in the on position.
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No Water Flowing
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1. No Power.
2. Gun, Nozzle, or Hot Water Coil plugged.
3. Unloader Malfunctioning.
4. Pump sat too long with no water. (Pressurize the inlet to try and correct.)
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Low pressure
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1. Tip is too big/worn.
2. Pump inlet has an air leak
3. Unloader is bypassing water.
4. Pump is bypassing water.
5. Heating Coil scaled up and restricting flow.
6. Too many hose repairs or pipe too small for flow.
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Surging pressure
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1. Tip is slightly plugged.
2. Water inlet is plugged or has air leak.
3. Malfunctioning unloader.
4. Heating Coil scaled up and restricting flow.
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Pulsation
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1. Plugged or malfunctioning check valves.
2. Cracked plungers.
3. Malfunctioning unloader.
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Water in oil
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1. Plunger rod oil seals no good.
2. Cracked plungers.
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Water dripping from
behind pump manifold
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1. Pump needs to be repacked.
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