Washing Machine Diagram / August 28, 2018 / Magnolia Covarrubias.
Washing machine pressure switches directly control the hot and cold water inlet solenoids and so are rated for quite high currents - 15A at 230V AC is typical. So for low-voltage DC applications, the switches can certainly cope with (say) 5A. This means that, for most loads, a relay won't be needed.
Exceptions. I’m talking about the UK. It seems that there are plenty of schematic’s and wiring diagrams available for American appliances on USA or Canadian repair sites, but not so much for the UK. Some washing machines and other appliances have been known to have a wiring schematic under the lid. I know Miele and a few other quality appliance manufacturers used to place a basic wiring schematic on top of the soap dispenser or underneath the lid. This does not happen on most washing machines though, especially the cheaper ones and they are often very basic
Range becomes larger. While we haven't tried it, you could probably stop the switch from closing until you had 15 to 20kPa of pressure. Note,however, that the rubber diaphragm isn't designed to withstand these. Pressure levels, so there may be some long-term reliability problems. So what uses can be made of these switches? That depends on your imagination, but here are some suggestions:
Typically, washing machine pressure switches have a large sensing diaphragm that's about 60mm or so in diameter and three quick-connect male terminals. One connection is common, while the others are for normally open (NO) and normally closed (NC) connections. A set-point adjustment mechanism is built in (it's directly controlled by the 'water level' knob) and the switch opens and closes with audible clicks.