WMF 800 - 2;3.5.4.1 Operation of the Brewing Valve and Release Valve T2-18

Engin eering
T2-18
© WMF800 / 900 / 1000S / 1000proS Edition 07/2014 - KMT
2/3.5.4.1 Operation of the brewing valve and release valve
AT-pieceisbuiltintothereleasevalveinthebrewingwaterinlettothebrewingunit.
Thereleasevalveiscontrolledthroughtheprocessdescribedbelow.
When heating
Thebrewingvalvelimitsthepressureintheboilersystemtoabout0.4MPa/4bar
duringtheheatingphases.Theexcesswaterisguidedtothedriptraythroughthe
releasevalve,whichisopenduringheating.
During the pre-infusion before the brewing cycle
(prehandling of the ground coffee)
 Thepumpswitcheson,thebrewingvalveandreleasevalveopen
System pre-warms
The water exits out the release tubing into the drip tray
 Thereleasevalvecloses
The brewing water for pre-infusion is fed to the ground coffee
 Thepumpandbrewingvalveremainactiveduringthepre-infusiontime
After the brewing process
Afterbrewing,thebrewingpressureisreducedviathereleasevalveintothedriptray.
Duringthebrewingprocess,ifthepumpswitchesonintheloweringoperation,the
brewingpressureisreducedviathereleasevalveintothedriptray.
2/3.5.4.2 Valve
Ifavalveisreplaced,thenon-wearing
componentsofthesolenoidvalve
remainonthecoffeemachine.
Therearenoprovisionsforreplacing
aplungeroraplungerguide.
Eitherthesolenoidorthebasecanbe
replaced.
Technical service instructions
Theowdirectionisshownonthevalve.
Thebrewingvalveisinstalledoppositethedirectionofow!
Illustration, see water supply assembly and valves
chapter 2/3.5.4