Bunn ES2SA Group head Espresso extraction chamber, Water Treatment, BUNN Espress, Features

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Group head (Espresso extraction chamber)

BUNN Espress™

FEATURES

ES•2A™/ES•2SA™

IMPORTANT: None of the high pressure pumps found on the market can operate without water for a period of more than approximately ONE MINUTE, After one minute of dry operation the pump will seize and become unserviceable.

Should water be shut off disconnect pump from power supply immediately.

4 3 9

7

6

11

10

2

121

P-158

Group head (Espresso extraction chamber)

The group head-espresso extraction chamber is where the coffee infusion takes place. After extraction, an electric pressure valve automatically discharges the accumulated pressure. When the coil (12) of the electro-valve receives an electric current, causing the plunger (10) to move, thus closing the discharge valve

(2)and opening the water intake valve (9) allowing the water to pass towards the shower (4) through the sprayer (3). This is when the brewing process (infusion) begins.

The bubbling effect is produced by an interchange between air, contained in a bubble formed in the chamber, and water which progressively increases it’s pressure on that bubble. The mixture of air and water produced then falls on coffee previously dampened by the infusion process. When the liquid extraction process of the coffee is complete, excess pressure contained in the filter holder is then released through a discharge valve (2). The atomizer (1) directs the water being discharged to the opening to avoid it’s splashing outward.

WATER TREATMENT

It is essential to treat water entering the brewer to prevent lime scale build up in the boiler tank and other plumbing. Recommended treatments are reverse osmosis or softening. Polyphosphate type treatment for scale reduction, which works well on conventional coffee brewers, is not effective for espresso equipment.

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Contents DISCONTINUED VERSION The information in this manual BUNNEspressE S 2A TM / ES 2SA TM ESPRESSO/CAPPUCCINO COFFEE BREWERSPage Installation BUNN EspressINDEX ES2A/ES2SAWARRANTY 00831.0000F 3/98 1988 BUNN-O-MATIC CORPORATION USER NOTICESREAD THE ENTIRE OPERATING MANUAL BEFORE BUYING OR USING THIS PRODUCT Liquid-Steam-SurfacesLEVEL FEATURESHOT WATER RINSE DISPENSING TUBE AND STEAM DISPENSING TUBE WATER FEED TAPWATER TREATMENT Group head Espresso extraction chamberPLUMBING REQUIREMENTS PLUMBINGPLUMBING HOOK-UP L1 240V or L2 Gnd ELECTRICAL SPECIFICATIONSELECTRICAL ELECTRICAL HOOKUPSTART-UP INITIAL SETUPPREINFUSION PROGRAMMING PROGRAMMINGPUSH-BUTTON SET AUTOMATICS ONLY PROGRAMMING DOSIFICATIONSCOFFEE EXTRACTION BREWINGOBSERVATIONS CLEANING CLEANINGProbable cause TROUBLESHOOTINGProblem WARNINGSAUTOMATIC WATER LEVEL MALFUNCTION ALARM DOSAGE PULSOMETER MALFUNCTION ALARMPUSH-BUTTON BOARD CONNECTIONS BOARD REPLACEMENTBUNN Espress ES2A/ES2SA Espress REPLACEMENTPARTS BUNNDescription REPLACEMENT PARTSBUNN Espress REPLACEMENT PARTS ES2A/ES2SAP-235 Description 22711.0000 Solenoid rebuild kit22811.0000 Group assy.itemsDescription 22685.0000 Complete valve assyP-240 Description 22658.0000 22637.0000Complete assy Complete valve assy.- itemsDescription P-238 Water inlet hose supply to pump in P-237 Description 1 .................. Red push button on/off switch Description Replacement Parts Not IllustratedES2SA SCHEMATICP-243 P-244 ES2A