Grindmaster 250A, 250AB, 250RH-2, 115AB, 250RH-3 User Manual

Grindmaster 115 and 250 Series

Coffee Grinders

Operation and Instruction Manual

for

Models 115A, 115AB, 250, 250A, 250AB, 250-3A,

250RH-2 & 250RH-3

Table of Contents

Installation Instructions ..................................2

Set-up Procedures..........................................2

How to Operate ............................................2

Timer Adjustment ..........................................3

Grind Selector™ ............................................4

Coffee Grind Profile, Grind Adjustment ........5

Current, Protection, Circuit Breaker................5

Lubrication ....................................................5

Cleaning Instructions ....................................6

Removal and Reinstallation

of Upper Hopper Assembly ............................6

Shear Disc Replacement ................................7

Troubleshooting Guide................................8-9

Exploded Views ......................................10-18

Wiring Diagrams ....................................19-22

Grindmaster Corporation™

4003 Collins Lane
Louisville, Kentucky 40245 USA
[phone]
[phone] (USA & Canada only)
[phone] (Technical Service)
FAX [phone]
www.grindmaster.com

© Grindmaster Corporation, 1998
Printed in the USA

0108 Form # GR-373-04

Part# 85358

Prior authorization must be obtained from
Grindmaster Corporation for all warranty claims.

Model 250

Model 115

Model 250RH-2

115 & 250 Series Coffee Grinders Page 2

Installation Instructions

For Models 115A, 115AB, 250, 250A, 250AB, & 250-3A:

1. Please read this manual before operating the grinder.

2. Carefully remove grinder from carton.

3. Place grinder in position on shelf, counter or flat surface.

4. Plug grinder into 120V, 15A, grounded, electrical outlet. Do not use an extension cord.

5. Grind a small amount of whole bean coffee following operating instructions as described in this manual.

6. If there is any problem, consult the Troubleshooting Guide in this manual and also on the back of your grinder.

7. If you still cannot correct a problem, call Grindmaster Corporation’s Technical Service Department for help,

[phone] or [phone] (USA & Canada only) 8 AM - 6 PM EST.

For Models 250RH-2 & 250RH-3:

1. Please read this manual before operating the grinder.

2. Remove the flat cardboard insert. Remove the cardboard insert on top of the
grinder. Next, remove the small box next to the grinder (hopper enclosed).
Next, remove corner supports and then remove the grinder. Lastly, remove the
second hopper.

3. Place grinder in position on shelf, counter or flat surface.

4. Plug grinder into 120V, 15A, grounded, electrical outlet. Do not use an
extension cord.

5. Fill hoppers with whole bean coffee and place on grinder. Make sure the base
of each hopper is seated in its designated area (see Figure A). See
“Removal and Reinstallation of Hopper Assembly” section on page 6 for
detailed instructions.

6. Grind a small amount of whole bean coffee following operating instructions as
described in this manual.

7. If there is any problem, consult the Troubleshooting Guide in this manual and
also on the back of your grinder.

8. If you still cannot correct a problem, call Grindmaster Corporation’s Technical
Service Department for help:

[phone] or [phone] (USA & Canada only) 8 AM - 6 PM EST.

Instructions

Your new coffee grinder is easy to operate and maintain. Before you place it in service, please have all personnel
familiarize themselves with these instructions; then keep this manual in a convenient place for ready reference.

Set-up Procedures

1. You, the user, must determine the quantity of coffee you want to dispense as various types of coffee and
brewing equipment require different quantities to obtain a quality cup of fresh ground, fresh brewed coffee.

Note: Because of the inherent properties of some decaffeinated coffee, it may be necessary to dispense a slightly greater
amount to achieve the desired level of flavor extraction as in regular coffee. This should be evaluated based on the coffee
you use as well as the brewing equipment used.

2. Adjust the timer inside the grinder if necessary, to dispense the desired weight of ground coffee (see Timer Adjustment
Section on page 3). All grinders are factory set to deliver approximately 2 ounces of ground coffee. This weight is
approximate, as the density of all coffee beans is not the same. The only way to ensure the desired portion is being
dispensed is to weigh the coffee after it has been ground.

3. The grind texture can be adjusted, if necessary, to a finer or coarser grind (see “Grind Adjustment” section on page 5).
The grind is factory set to deliver a standard autodrip grind.

How to Operate

1. Fill the hopper with the appropriate amount of whole bean coffee.
250RH Models: Place full hoppers on machine making sure the base of each hopper is seated in designated area.
(Refer to Figure A)

2. Place the brew basket with coffee filter on rails (or basket arms).

3. Choose the type of coffee you wish to grind by pressing the rocker selection switch.

4. Push the start button on the front of the grinder.

5. When grinder stops, remove the brew basket.

Figure A

correct

incorrect

Timer Adjustment

The timer is preset at the factory, but should adjustments be required, follow the instructions below to set the grind times.

Note: The grinder power must remain ON for timer adjustments.

Digital Grinder Timer Adjustments (All Models)

1. To access timer, remove the timer cover by removing the mounting screws and pulling the cover away from the casing.

2. To light up the display on the board and check the time setting, depress either one of the two square buttons located next to
the display one time.

3. To change the displayed setting, press and hold either the left or right square button until the desired setting is reached. The
left button lowers the displayed value; the right button increases the displayed value. The time values are set in seconds and
tenths of a second.

4. Refer to chart above for approximate timer settings.

Note: For accuracy you must weigh the coffee and make appropriate adjustments.

5. In order to store this desired value you must press the grinder start switch once.

Note: If start switch is not pushed, the last value stored will be used when you return to grinding mode.

6. Once the timer is adjusted, reinstall the timer cover.

Page 3 115 & 250 Series Coffee Grinders

AMOUNT TIME AMOUNT TIME
DESIRED SETTING DESIRED SETTING

(OZ.) (SECONDS) (OZ.) (SECONDS)

0.5 1.0-1.3 6 13.0-15.8

1.0 2.1-2.6 7 15.2-18.4

1.5 3.2-3.9 8 17.4-21.1

2.0 4.3-5.3 9 19.5-23.7

2.5 5.4-6.6 10 21.7-26.3

3.0 6.5-7.9 12 26.1-31.6

3.5 7.5-9.2 14 30.5-36.9

4.0 8.6-10.5 16 34.8-42.1

5.0 10.8-13.2 18 39.2-45.0

115 & 250 Series Coffee Grinders Page 4

Grind Selector™

For Models 115AB and 250AB:

Models equipped with a Grind Selector™ are designated with a “B” at the end of the model number (Model 115AB & 250AB). If
your grinder is equipped with a Grind Selector™, refer to the following information:
The Grind Selector™ allows you to set the grinder to coarse or fine on any of the 250AB four grind selections:
regular small, regular large, decaf small, or decaf large.

The following are some recommended use conditions:

Coarser Settings Regular Settings

Larger portions - 8 oz or more Smaller portions - 7 oz. or less
(urns) (bottle brewers or airpots)
Decaffeinated coffee Regular coffee

The fine grind setting on this grinder has been pre-set at the factory to deliver coffee ground to normal drip
specifications. Should you wish to make an adjustment please follow these steps:

To Adjust the Fine Grind

For Models 115AB and 250AB:

Tools Required: Adjustable Wrench, Phillips Screw Driver, Large Blade Screwdriver

1. Unplug grinder.

2. Remove upper front plate.

3. Loosen the fine grind adjusting screw lock nut (see Figure B).

4. Hold solenoid shut while turning adjusting screw clockwise to
make the grind finer, counter-clockwise to make the grind coarser
(see Figure B). We recommend that you do not turn the
adjusting screw more than two notches on the scale before
testing the new grind setting.

NOTE: Be sure that when adjusting the grind that you do not adjust too fine, causing the burrs to touch each other (a sound of
metal scraping metal). This could cause damage to the burrs or motor.

5. After the adjustment has been made, tighten adjusting screw lock nut. Do not allow the fine grind adjusting screw to expose
more than three threads on the outer side of the arm or it could loosen during operation.

6. Assemble front plate to front of the grinder.

To Adjust the Coarse Grind

For Models 115AB and 250AB:

Tools Required: Adjustable Wrench, Phillips Screw Driver, Large Blade Screwdriver

1. Unplug grinder.

2. Remove upper front plate.

3. Loosen the fine grind adjusting screw lock nut (see Figure C).

4. Pull the solenoid plunger toward you until it contacts the coarse
grind adjusting screw (see Figure C). Then turn the adjusting
screw clockwise to make the grind finer, counter-clockwise to
make the grind coarser. We do not recommend that you turn the
adjusting screw more than one and a half turns before testing the new grind setting.

5. After the adjustment has been made, tighten the adjusting screw lock nut.

6. Assemble front plate to front of grinder.

Figure B: Fine Grind Adjustment

Figure C: Coarse Grind Adjustment

Fine grind

adjustment

screw

Coarse grind

adjustment screw

Page 5 115 & 250 Series Coffee Grinders

Coffee Grind Profile

Before shipment, this grinder has been tested with coffee and has been accurately adjusted to deliver a
standard autodrip grind.

The Grinding Burrs are made of an extremely hard and wear resistant alloy. From time to time, grind
adjustments (see instructions below) may be necessary as the burrs wear. If the grind runs coarser than
expected after normal adjustment and the grind time has increased, the burrs may have excess wear and should be
replaced. The burrs are warranted for 3 years or 30,000 pounds of coffee. See your warranty for details. New burrs should
always be installed as a pair, never one or the other, as they are accurately ground and lapped in pairs. Old burrs cannot be
resharpened.

Grind Adjustment

For Models 115A, 250, 250A, 250RH-2, 250RH-3

Tools Required: Phillips and Large Blade Screwdrivers, Pliers

In order to adjust the grind follow these steps: (see Figure D)

1. Remove Upper Front Plate by removing the four screws in the corners.

2. Loosen Adjusting Screw Lock Nut by turning counter clockwise.

3. Turn slotted Adjusting Screw clockwise to make grind finer or
counter-clockwise to make grind coarser. Generally a 1/8 to 1/4 turn
will provide the desired adjustment.

Note: Use dial on grinder cap as reference. Do not turn more than
one notch before testing new Grind Adjustment.

4. After adjustment has been made, tighten Adjusting Screw Lock Nut.

5. To visually inspect grind adjustment, test grind a small portion of coffee
and re-adjust if necessary.

Note: Adjusting the grind may alter the portion of coffee dispensed. After grind adjustment,
weigh portion and adjust, if necessary (see “How to Adjust the Portion”).

Current

It is absolutely essential that full voltage and amperage always be available as it takes full power to grind
coffee. NEVER connect to an overloaded line or a two or three way plug, otherwise serious damage to the motor may result.

Do not use an extension cord.

Protection

This grinder is equipped with both a circuit breaker and a shear disc to protect motor and burrs if a foreign object, such as a
nail or rock, gets into the coffee.

Circuit Breaker

This grinder is equipped with a circuit breaker to protect the motor from overloading. When the circuit breaker operates, the
reset button will pop out approximately 1/4” which cuts off the power to the grinder. The reset button is located above the
power cord on the back of the grinder. To reset the circuit breaker, push the reset button in. You will hear a click as it resets.
If the grinder does not operate after resetting the circuit breaker, there may be an obstruction in the grinding mechanism that
is stalling the motor. In this case, the Grinder Head should be cleaned out as described in the Shear Disc Replacement
section of this manual.

Lubrication

All bearings have been oiled for life. No further oiling is necessary.

Figure D: Grind Adjustment

Adjusting Screw

Lock Nut

(86340)

Adjusting Screw

(86341)

Grinder Cap

(87131)

Cleaning Instructions

The outside of the machine can be cleaned with a damp cloth or common household polishing wax. Grinding parts should
be cleaned with a stiff brush or dry cloth. Do Not Use Water. See “Shear Disc Replacement” for instructions on assembling
and disassembling of grinder parts. Before reassembling, wipe motor shaft with 2 or 3 drops of common household lubricat­ing oil in the area of feedworm engagement to make assembly easier.

For Models 250RH-2, 250RH-3:

Regular usage of the coffee hoppers will cause oils to accumulate on the inner surface, requiring occasional cleaning.

1. Remove hopper from grinder and empty all beans.

2. Use a soft, damp cloth with a small amount of liquid soap and clean hopper. Use a clean, damp cloth to remove the
soap residue. Do not immerse or fill hopper with water.

3. Allow hopper to completely air dry before refilling with beans.

4. Once the hopper is dry, refill with whole bean coffee, cover and replace on grinder.

Shipping Bracket Removal

NOTE: Shipping bracket must be removed prior to removal of

upper hopper assembly.

Models 250, 250A and 250AB are equipped with shipping bracket.
Remove bracket prior to installation. (see Figure E)
Tools Required: 1 Phillips screwdriver.

1. Using the Phillips screwdriver, remove the screws and the bracket
located at the back of the grinder.

2. Do not discard the screws and bracket. The bracket should be re-installed
on the grinder prior to transporting or shipping.

Removal and Reinstallation of Hopper Assembly

For Models 250, 250A, 250AB, 250-3A:

1. Remove Upper Front Plate by removing the four screws in the corners

(Shipping bracket must be removed prior to removal of upper
hopper assembly. See instructions and diagram above.)

2. Lift Upper Hopper Assembly while rotating the Assembly slightly
upward (see Figure F).

3. Pull the Assembly forward, toward front of unit and out.

4. To reinstall hopper, ensure the Drive Pins are in vertical position.
(see Figure G)

5. Ensure that Drive Links are in horizontal position.

6. Insert the rear slots of the Upper Hopper Assembly into the rear tabs
of the motor bracket.

7. Rotate assembly downward.

8. Reassemble Upper Front Plate.

9. Put the (4) screws back into Upper Front Plate and tighten.

For Models 250RH-2, 250RH-3:

1. To remove hoppers, grasp hopper by handle and lift up
approximately 1/4” and pull hopper back and out of
grinder. The bottom bean shut off valve will close
automatically, preventing spillage of beans.

2. Once hopper is removed, it can be refilled or cleaned if necessary.

3. To reinstall hopper, grab by handle and set bottom back of hopper on
left or right side of grinder, making sure that the drive link is properly
oriented (see Figure G).

4. Push hopper all the way back until it settles in it’s designated space (see Figure A).

NOTE: Hopper must be in place in order for that side of the grinder to operate.

115 & 250 Series Coffee Grinders Page 6

Figure F: Upper Hopper Assembly

Removal and Reinstallation

Figure E: Shipping Bracket Removal

Figure G: Positioning of the

Drive Pins and Drive Links

Model 250

shipping bracket

The bracket may be

left on grinder, but

must be removed

prior to servicing.

Page 7 115 & 250 Series Coffee Grinders

Shear Disc Replacement

If the motor should run and no coffee is dispensed, the shear disc release may have operated. Should this occur,
perform the following operations in the sequence given (see Figure H).

Tools Required: Phillips Head Screwdriver and Pliers

1. Unplug machine.

2. Remove the Upper Front Plate of the grinder to provide access to the grinder mechanism.

3. Remove the Grind Cap by taking out the 2 Thumb Screws.

4. Pull out the Revolving Burr and Feedworm Assembly. Clean out the Grinder Head, removing all coffee particles
from inside of the Grinder Head and the Grinder Cap so that it can be reset properly.

5. Check that no obstruction has been caught on the surface of the teeth of either burr.

6. Remove the Shear Cap and broken pieces of the Shear Disc. You are now ready to reassemble the grinder
mechanism.

7. Slide the Burr and Feedworm Assembly back onto the Motor Shaft making certain that the tongue of the shaft
engages the slot in the Shear Drive.

8. Insert a new Shear Disc by aligning the slot in the Shear Drive with the slot in the hub of the Feedworm.

9. Reassemble the Shear Cap and Grinder Cap. Make certain the Grinder Cap is screwed on tight and is sealed
properly against the head, not angled or mis-aligned. Otherwise a proper grind cannot be obtained.

10. Reassemble the Upper Front Plate. Your grinder is now ready to grind.

Figure H: Motor Assembly

Adjusting Nut
(86340)

Decal, Coarse-Fine
(84884)

Shear Cap
(86355)

Shear Disc
(86123)

Burr Set

(85281W)

Tension Spring

(86118)

Thrust Collar

(86304)

Grind Head

(84171S)

Gasket, Hopper Foam
(88211)

Motor

(86419)

Nut
(86864)

Machined Spout (86218)

Deflector (86220)

Screw (86217)

Gasket, Portioner to Head
(71419)

Adjusting Screw

(86341)

Thumb Screw
(86819)

Bearing, Adjusting

(86140)

Grind Cap
(87131)

Shear Drive
(86154)

Feedworm

(85185K)

Screw
(86812)

Screw
(86148)

Spring, Chaff Mixing

(86146)

Revolving
Burr