MYDAX 1M9W-S Maintance Manual

advanced temperature control technology

MYDAX, INC.

INSTRUCTION/OPERATIONS MANUAL

1M9W-S WATER COOLED CHILLER

Serial Number 120-07XX

MYDAX, INC.

12260 Shale Ridge Road

Auburn, CA 95602

[phone]

FAX: [phone]

March 2001

TABLE OF CONTENTS

I. SPECIFICATIONS ....................................................................................................... 1

II. SYSTEM OVERVIEW ................................................................................................. 2

III. INSTALLATION ......................................................................................................... 4

IV. FRONT PANEL CONTROLS ..................................................................................…… 5

V. ERROR MESSAGES ................................................................................................... 7

VI. DIAGNOSTIC DISPLAYS .......................................................................................... 8

VII. SERVICE & WARRANTY .......................................................................................…. 11

VIII. RESHIPPING & LONG-TERM STORAGE PREPARATION ............................ ..................… 12

IX. APPENDIX A: RS-232C SERIAL INTERFACE OPERATION

X. APPENDIX B: DRAWINGS

Lawrence Berkeley Laboratory

Mydax, Inc. 1M9W-S Water Cooled Chiller

SPECIFICATIONS

SYSTEM CAPACITIES

Cooling Capacity @ +20°C 2500 Watts

Coolant Temperature Setpoint Range +15°C to +25°C

Coolant Output Temperature Stability

Polypropylene Reservoir Volume 10 Gallons

Recirculating Coolant Low Conductivity Water

Coolant Flow/Pressure 10 Gpm @ 100 Psi (Bypass Provided)

Recirculating Supply/Return Fittings 1" Stainless Steel FPT

Condenser Water @ 75°F 1.5 Gpm Required (∆P = 20 Psi)

Condenser Water Connections 1/2" Stainless Steel FPT

Electrical Service 208/230 volt, 60 Hz, 3 phase, 20 amp

Physical Parameters 42"H x 24"W x 33"D, 450 lbs.

STANDARD FEATURES

System is complete with microprocessor-controlled low-stress refrigeration circuit, recirculating pump and fluid
reservoir. R-22 refrigeration circuit uses all-brazed construction for extra strength. The heavy-duty frame is
constructed of welded steel tubing equipped with locking casters.

±

0.05°C

With 10' line cord and L15-30P plug.

The microprocessor-based control system includes an extensive monitoring capability including comprehensive
controls, error messages and diagnostics. System status is indicated via a two-row (40 characters each)
alphanumeric LCD (liquid crystal display) and with red light-emitting diodes (LED's). The control keyboard
employs membrane switches with a sealed polycarbonate overlay for protection from liquid spills. This chiller
is complete with a liquid-filled panel mounted pressure gauge, an internal pressure bypass circuit, a full-flow
10 micron particulate filter and an RS-232C Interface for remote control and monitoring.

SAFETY FEATURES

1. Warning & Error Messages: including coolant over-temperature warning & shutdown, low tank level warning
& shutdown and others (see ERROR MESSAGES section).

2. System Diagnostics: including coolant & freon temperatures, valve and heater drives and others (see
DIAGNOSTIC DISPLAYS section).

3. Integral compressor refrigerant high pressure protection.

4. Circuit breaker & contactor.

5. Interlock loop, including reset switch.

6. Thermal protection of pump and compressor motors.

7. Manufactured and wired in accordance with IBM Non-Product Safety Design Standards.

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Mydax, Inc. 1M9W-S Water Cooled Chiller

SYSTEM OVERVIEW

System Fluid Schematic

Refer to drawing #B2343, the fluid schematic. The heart of the design is the evaporator valve. This is a thermal-electric
expansion valve, controlled directly by the system's embedded microprocessor. Hermetically sealed, it consists of a
spring-loaded needle valve in contact with a bimetallic plate. The plate is wound by a coil of wire connected to terminals
on top of the valve. The curvature of the plate, and therefore the position of the needle valve, varies with its temperature
which is controlled by electrical current flow through the coil. So by controlling the duration of electrical pulses applied
to the valve terminals, the microprocessor opens the valve to a precisely determined point. This passes a precisely
determined flow of freon to the evaporator, allowing for exceptionally stable recirculating temperatures. This system
is designed to control the recirculating output temperature to ±0.05°C across the system operating range.

The microprocessor sets the exact position of the valve based upon the system heat load. If the load increases, the
evaporator valve is opened slightly, passing more refrigerant. If the load decreases, the valve is closed slightly, passing
less refrigerant. During normal operation, the position of this valve stays nearly constant. Only major changes in heat
load or system-wide power cycling cause large changes in the valve opening. In the case of a step-wise change in heat
load, the microprocessor quickly drives the valve to the new setting and refrigerant flow soon settles at the proper level.

The valve drive setting is based primarily upon data received from RTD's (resistance temperature devices) located about
the circuit. The drawing shows RTD's at the evaporator valve, at the discharge line from the pump, at the reservoir and
between the condenser and receiver. The microprocessor "reads" these and other sensors constantly and sets the
refrigerant valve accordingly.

Thus refrigerant flow is truly proportioned, through a valve which only rarely cycles all the way open or shut. Besides
precise temperature control, this allows continuous compressor operation without the normal addition of cycling, and
therefore failure-prone, pressure-actuated hot gas bypass valves. All other refrigeration circuit components are used as
in conventional systems. All permanent copper joints in the refrigeration circuit are brazed for extra strength. Much of
the circuitry is insulated to eliminate cooling capacity loss and unpredictable operation due to drafts or fluctuating
ambient air conditions.

This system is designed to recirculate water. It is not designed to recirculate solutions of automotive antifreeze.
Approximately 10 gallons are required to fill the polypropylene reservoir. The heating elements are stainless steel
cartridge heaters. The freon evaporator is a coaxial heat exchanger, located in the recirculating return line leading to the
reservoir.

The reservoir is fitted with two level sensors. One level sensor drives a FILL TANK alarm at the main panel, indicating
coolant level has dropped somewhat. The second sensor, the TANK EMPTY sensor, is connected to the safety interlock
loop and shuts the system down if tripped. Note that "empty" is a relative term only. The real function of this sensor
is to prevent the coolant level from dropping so low as to expose the pump suction line.

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Mydax, Inc. 1M9W-S Water Cooled Chiller

System Electrical Diagram

Refer to drawing #B2344, the system electrical diagram. The central component of the electrical system is the M1001
controller. It is microprocessor-based and communicates with and/or controls various other circuit boards and
components. Most controller circuitry is laid out on circuit boards mounted in the main control cabinet. The controller
is powered as long as the system circuit breaker is set, receiving 24 VAC power from a bulkhead-mounted transformer.

The controller "reads" the RTD's in the system via board M1002. RTD's are included for the recirculating output
temperature and the reservoir, as well as for the freon circuit. Also routed through this board are the 100 and 120 •
precision RTD calibration resistor circuits. The evaporator valve drive signal is routed through board M1004, as is the
phase detector circuit.

The system interlock loop is controlled by the M1002 circuit board. In this application the interlock loop consists of the
freon high pressure switch, the tank over-temperature switch, the TANK EMPTY level sensor, the RESET momentary
switch, one power relay coil and a relay pole (1R 5-8). The RESET switch serves to feed power to the relay, which
energizes the contactor. When energized, the contactor feeds power back to the relay so the RESET switch may open
up without cutting off power to the relay. If the freon pressure switch, the over-temperature switch or the level sensor
trips, power to the loop is interrupted. The microprocessor senses this via the M1002 board. Provided the system has
power, if the loop trips out, the controller drives the PUSH RESET error message. The loop must be reset when the fault
condition is resolved.

The M1002 board also routes signals for the FILL TANK level sensor. If this sensor trips, the microprocessor drives
the FILL TANK error message.

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Mydax, Inc. 1M9W-S Water Cooled Chiller

INSTALLATION

POWER CONNECTION

This chiller requires a 20 amp or larger circuit, 208/230 volt, 60 Hz, 3 phase and is equipped with a line cord
and twist-lock L15-30P electrical plug.

PLUMBING INTERFACE CONNECTIONS

The chiller's 1" female pipe thread (FPT) fitting labeled "TANK OUT" must be plumbed to the inlet of the
device to be cooled. The outlet of the device to be cooled must be plumbed to the chiller's 1" FPT fitting
labeled "TANK IN". This system is equipped with a ½" FPT fitting labeled "DRAIN". It may be desirable to
install a valve at this location prior to the initial filling of the reservoir, for the convenience of future draining
procedures.

The condenser cooling water supply must be plumbed to the chiller's ½" FPT fitting labeled "CONDENSER
IN". The chiller's ½" FPT fitting labeled "CONDENSER OUT" must be plumbed to either a drain or the return
path of the condenser cooling water circuit. Verify that condenser cooling water into and out of the chiller is
unobstructed. Obstructions may cause loss of cooling capacity and eventual overheating.

Both the recirculating loop and the condenser cooling water loop are under pressure when the system is
operating. Check all fluid interface connections now to ensure against leaks.

CIRCUIT BREAKER

Set the circuit breaker mounted on the front of the system. Upon setting the circuit breaker, a message similar
to the following appears on the 2 by 40-character main display:

This display indicates that the system's phase monitor circuit is checking for correct electrical power phase
relationship. Should a live and ground line be reversed, the phase detector reads PHASE MISSING. Correct
the error and the controller no longer indicates PHASE MISSING. If the display reads PHASE REVERSED,
disconnect and switch two of the three phases.

FILL RESERVOIR

To fill the system's reservoir, unscrew the fill plug on the top of the vertical stand-pipe for the tank and pour
in the recirculating fluid. If the system is powered before the tank is filled, the "FILL TANK" error message
is displayed at the main panel, the alarm LED is lighted and the audible alarm sounds. Filling the tank
eliminates the alarms. Replace the plug.

Output --- Warmup Delay --- Local Set

20.02°C 20.0°C

WARNING

The system should be powered for a period of ½ hour before starting, to

allow the crankcase heater to separate the refrigerant from the oil.

PUSH RESET BUTTON

The Reset button, located below the main panel, must be pushed upon powering the system. This resets the
power safety interlock loop, which protects the operator and electrical circuitry.

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Mydax, Inc. 1M9W-S Water Cooled Chiller

FRONT PANEL CONTROLS

All Mydax chillers are controlled by a microprocessor which is accessed via the system control panel. System controls
are simple, yet powerful and in concert with built-in diagnostics and error messages, are exceptionally comprehensive.

POWER LED:

RESET:

START:

STOP:

MUTE ALARM:

SET:

Indicates unit is powered (the circuit breaker is set).

Must be pressed prior to system start-up to energize the interlock loop.

Starts compressor and pump and turns on LED's. Once the start-up routine is complete the
display changes to the MAIN DISPLAY:

Output --- MYDAX --- Local Set

20.02°C 20.0°C

Shows the actual Output Temperature and Setpoint Temperature in °C. Also indicates that
the local SET TEMPERATURE MODE can be enabled.

Stops both the compressor and pump and blanks the display.

May be used to deactivate audible alarm for 10 minutes, leaving alarm LED on. Pressing the
CLEAR key reactivates the alarm, which sounds until the fault condition is eliminated or the
MUTE ALARM switch is depressed again. Pressing MUTE ALARM when no alarm is
active causes the alarm to sound once and the TEST ALARM display to appear.

Enables SET TEMPERATURE MODE. SET MODE is disabled from panel if an alarm is
active or if the unit is in REMOTE. To set, depress:

TEST:

ENTER:

CLEAR:

MODE:

ARROW KEYS:

SET:

ARROWS KEYS:

"." (DECIMAL):

KEYPAD:

CLEAR:

ENTER:

Initiates Test Mode. See description under DIAGNOSTIC DISPLAYS section of this manual.

Enters temperature selections while in the SET mode.

Erases incorrect temperature selections; exits Test Mode; clears Mute Alarm selection.

Toggles between the RS-232C remote control mode and Local Set mode.

Changes temperature setpoint by 0.1° or 1°C increments/decrements; toggles tank

"Set Mode" appears at the right of the display. Cursor flashes at
"units" digit of the temperature display.

Changes temperature setting in one degree increments unless "."
(decimal) key is depressed.

Moves cursor to the "tenths" digit of the temperature display and
causes arrow keys to change setting in tenths of a degree.

Changes temperature setting by entering numbers directly.

Erases an incorrect entry.

Selects temperature setting and deselects SET mode.

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Mydax, Inc. 1M9W-S Water Cooled Chiller

temperature, setpoint temperature and evaporator data view modes for multiple channel
systems.

"." (DECIMAL):

RUN PUMP:

X & Y:

Z:

EMO SWITCH:

Display shows model number and software revision date and copyright:

1M9W-S 2001.01.18
Copyright 2001 Mydax, Inc.

Inactive in this system.

For future use.

See Test Panel 9 in the Diagnostic Displays Section.

This is a large red emergency off switch mounted on the left of the main panel. It shuts down
the entire system, excluding the controller.

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Mydax, Inc. 1M9W-S Water Cooled Chiller

ERROR MESSAGES

A unique feature of Mydax systems is the error messages displayed on the 2 by 40-character liquid crystal display (LCD).
The microprocessor constantly checks various points and parameters throughout the system and automatically displays
messages when error conditions are sensed. Many displays are announced by an audible alarm and LED indicator. The
error message persists until the fault condition is resolved, provided that the fault condition was not fatal, resulting in
a system shutdown.

Condenser Hot

Fill Tank

Tank Too Hot

Push Reset

Phase Missing

Indicates high discharge pressure condition with temperature over +50°C. This is a warning message
only. A separate mechanical overpressure switch, part of the safety interlock loop, shuts the system
down in case of an overpressure condition. The purpose of this message is to allow maintenance
workers to correct the problem at an early stage. (Caused by a clogged filter, low or warm condenser
cooling water flow or condenser scale build-up.)

Indicates low tank liquid level.

Indicates that the reservoir temperature is more than 10°C above the highest allowable set point.
Microprocessor shuts down the system.

Indicates that the reset button has not been pushed since the last system power-up or that the system
interlock loop has a fault condition.

A series-wired safety interlock loop protects all Mydax systems, disconnecting AC power from nearly
all circuitry. The loop consists of the freon pressure switch, tank "hot" sensor and low level switch.
If any link in the loop is opened, the "Push Reset" error message is displayed. Once the fault is
corrected, the Reset button must be used to re-establish loop integrity. The reset button must also be
pushed at system power up.

Indicates that one or more electrical phases are missing.

Phase Reversed

Low AC Line

Open RTD

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Indicates that electrical phases are incorrectly connected. Reverse any two legs.

Indicates a low voltage condition exists on the input AC line.

Indicates that an RTD connected to the M1002 Input Board has failed and that the system has shut
down to prevent damage due to lack of data. The RTD at fault may be located by accessing Test Panel
#8. The RTD must be replaced for the system to operate again.

Mydax, Inc. 1M9W-S Water Cooled Chiller

DIAGNOSTIC DISPLAYS

Mydax chillers are provided with a computerized self-diagnostic capability. This system is equipped with 9 different
test panels, which are accessed by pressing the TEST key, followed by the test panel number. Diagnostic mode is
terminated by pressing the CLEAR key, and results in a display similar to that below:

MAIN DISPLAY

Output --- MYDAX --- Local Set

20.02°C 20.0°C

Diagnostic messages are displayed on the main 2 by 40-character LCD. Display #5 automatically appears when the
TEST key is first depressed. Once in diagnostic mode, other displays can be selected by depressing number keys 1
through 9. The following describes each of the test displays:

TEST PANEL #1:

Valve 7 Htr 8
Avg Valve 5 Htr 6

Numbers represent the drive signals for the evaporator valve and tank heater. The range is 0 (minimum) to 20
(maximum drive). Each digit represents 5% of the available 24VDC drive voltage. Avg Valve shows a 32
second running average of the valve's drive, displayed above it.

TEST PANEL #2:

This display shows the refrigerant circuit RTD temperatures in °C. The display reads:

Limit = Max Evaporator Temp Suct = Suction Temp Psig = Suction Pressure
Sup.Ht = Superheat Temp SHavg = Avg Super Ht Temp Cond = Condenser Temp

The condenser reading is a direct indicator of condenser temperature and pressure. The microprocessor sends
the CONDENSER HOT error message if the condenser temperature exceeds +54°C.

TEST PANEL #3:

The first 3 sets of 4-digit numbers are hexadecimal. They represent correction values for the slow gain servos
for up to 3 reservoirs. The function of this servo is to dynamically adjust the main temperature control servo
to near zero error and thereby maintain temperature stability.

The first 2 digits in each set of 4 show the gain offset. Each increment equals 0.05°C, so 14 Hex = 20 decimal
= 1.0°C. This value is internally subtracted from the operator-entered temperature setpoint if the actual
temperature is above the setpoint, thus reducing the coolant temperature. When the actual coolant temperature
is below setpoint, the main servo is driving a heater and no adjustment is made to the setpoint. The setpoint
offset is continuously monitored by the controller and adjusted according to current conditions.

4.0 -4.8 48.2 35.0
Limit Suct Psig Sup.Ht SHavg Condr

302B 0000 091F Z 0.00 G 51.95 14.4
SS-1 SS-2 SS-3 RTD Reference SH Avg

The second 2 digits in each set of 4 show the time prescaler. This is a counter which increments or decrements
once a second and times the next update of the setpoint offset. A typical value is 20 seconds per offset change.
When the count reaches "00", the offset may or may not be changed and the count resets to "0A" Hex (10
decimal). Together these numbers show that the controller is internally changing the control setpoint to
maintain temperature stability, and give the magnitude and timing of the change.

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