Scale nozzles plugged and less pressure due to cleaning chemicals


Scale, nozzles plugged and less pressure due to cleaning chemicals

While owning and operating a hot water pressure washer one of the considerations for service is in a place that you cannot see.

The inside of the helical heat exchange coil can become partially or fully plugged with advanced age.  The TDS [total dissolved solids] from the nasty Arizona hard water accumulates inside.  The only way to check it is to put a gage just after the pump and read the Back pressure.  In a clean coil it should be about 50 lbs.  The 1600 degrees temp of the heater condenses the TDS into a calcium scale.

The use of soapy cleaning chemicals through the coil speeds up the internal build up.  We gage all the machines that come into the shop and when we are on a field service call. The means to dissolve the scale is to use a separate descale pump and an inhibited acid which is slowly fed into and recirculated until the gauge pressure goes back to normal. This solution is titrated to a PH of 7 so that it can be disposed of.

The sign of scale can be nozzle plugging or, a lessoning of pressure at the cleaning wand.

Anyway, be aware of this as the cost of a new heat exchanger is a goodly price…


Bill Sommers

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