Bacharach HGM-MZ Operating instructions

Bacharach | THE MEASURABLE DIFFERENCE | New Kensington, PA, USA | Dublin, Ireland | Toronto, Canada | mybacharach.com
BACHARACH Inc.
HGM-MZ Multi-Zone Monitor
Annual Maintenance
And Troubleshooting Guide
Service, Testing and Maintenance procedures

Bacharach | THE MEASURABLE DIFFERENCE | New Kensington, PA, USA | Dublin, Ireland | Toronto, Canada | mybacharach.com
HGM-MZ
Routine Annual Maintenance
And Operating Parameter Verification
These maintenance and service items and procedures below will be
referenced in the tech bulletins and operations manual and used by
customer service and technical support technicians when discussing parts
or service of the refrigerant monitor. Using this information allows the
installation technician to quickly identify the service points and make
maintenance measurements and adjustments to the unit quickly and
accurately.
Yearly maintenance is required to assure peak performance and accuracy
of the HGM-MZ multi-zone monitor. If the monitor is installed in areas of
high levels of dust and particulate it is recommended that semi-annual or
quarterly filter changes be made to prevent system faults due to purge or
zone restrictions.
During these maintenance procedures it is a good time to check the
diagnostic screen “DIAG” to verify that the detector voltage and pump
pressures and within optimum parameters. If they are not a voltage
adjustment or scheduled pump replacement could head off a system fault.
To verify monitor operation it is possible to use a bump gas test using
keyboard cleaner (dust destroyer) which is typically R134a purchased at
your local office supply store. If calibration type verification is required we
have “Gas Verification kits available which contain certified PPM levels of
test gas.
Please refer to the Tech Bulletins on the following pages for parts
identification, actual settings and adjustment sequence.

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HGM-MZ
Detector voltage and Reference voltage
adjustment.*
*Only If Required
Correcting and adjusting; Fault codes, Gain Set 200, Over
Range 2000, Zero 4000 and Clipping 8000
Figure 1
To correct for codes 200, 2000, 4000 and
8000 – from the front screen on the HGM
MZ select the top left block (under
STATUS) and press enter. This will take
you to the SETUP screen.
To enter service mode:
From the main sampling screen (figure 1) press enter two times that will take you to the SETUP
screen (figure 2) then move the cursor to the Service Mode entry box, then press enter, it will now
say (service mode confirm), press enter again, it will now say, (service mode quit), press enter
again, it will now say (service confirm quit), press enter again and if you did it correctly it will say
(service mode entry) again.

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Figure 2
At the setup screen you can view the current conditions by entering the diagnostic
screen “DIAG”. To make changes and adjustments you must first put the monitor in the
SERVICE MODE. Once in service mode select “SYSTEM”.
To access detector voltage and IR
voltage adjustment screen select
SERVICE MODE ENTRY – press
enter twice then select SYSTEM
and press enter.
To enter service mode:
From the main sampling screen (figure 1) press enter two times that will take you to the SETUP
screen (figure 2) then move the cursor to the Service Mode entry box, then press enter, it will now
say (service mode confirm), press enter again, it will now say, (service mode quit), press enter
again, it will now say (service confirm quit), press enter again and if you did it correctly it will say
(service mode entry) again.

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In the “SYSTEM SETUP” arrow down to “MORE” and press enter to get to the actual
adjustment screens.
In the “MORE” screen you have access to the “DET DIGIPOT” and “IR DIGIPOT”
voltage adjustments. Select the item you want by highlighting it and hitting enter. To
adjust and use the arrow keys move to it, then press enter which will allow you to see
the voltage and make the adjustments with the up and down arrow keys.
The detector digipot “DET DIGIPOT” voltage range should be between 4.20 to 4.28
VDC with the digipot three digit reference numbers between 120 and 255.
In the SYSTEM SETUP select
MORE and press ENTER to
get to the adjustment screens.
Record the DET DIGIPOT and
IR DIGIPOT readings for
reference.
Highlight DET DIGIPOT and
press enter to view the Digipot
and IR VOLTAGE.
Highlight IR DIGIPOT and
press enter to view the IR
VOLTAGE.

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Note - Go into IR DIGIPOT and
verify that the MW is not set outside
the range of 300 to 500 after
adjusting the IR detector voltage IR
DIGIPOT. A typical MW setting for a
sensor with Yellow tape is 325
without the tape it is approx 425.
To adjust the MW use
the up and down arrow
keys on the keypad.
Adjust the Detector Digipot Voltage
Range 4.20 to 4.28 with up and down
Sensor
No Tape
With
Digipot Reference
b

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HGM-MZ Sample pump flow testing
This procedure describes the correct method for testing the sampling pump in order to
determine its proper sample flow and vacuum.
HGM-MZ Pump Testing;
If the HGM- MZ is unable to pull a vacuum it will generally be due to one of two things, either the
pump is not running or failed, or there is a leak in a valve or valve stuck open in the manifold.
Flow detection is based on a minimum drop from ambient pressure and a minimum value above
vacuum, so a vacuum failure will generally result in a NO flow indication on all zones.
The pinch test can isolate the problem quickly. In the diagnostic screen observe the live
pressure "PRES", then pinch the tube on one side of the white disc (Hydrophobic filter) pinching
either side is OK. This will dead head the pump, a good pump will drop the pressure to
approximately 3 psia below the Ambient reading. If you get no change, the pump is not
working, the “EXHAUST” port is restricted, or there is a leak between the pinch point and the
pump.
If the pinch yields a good vacuum number, the problem is before the pinch in the valve
manifolds. One or more manifold valves are either stuck open or a failed valve driver board is
electrically holding it open. (See separate tech Bulletin on Manifold testing procedure)
Pump Pressure (PRES)
Pump Vacuum (VAC)
Ambient Air Pressure (AMB)
Indicates good or bad pump
operation
Enter Diagnostic Screen (DIAG)
From SETUP Screen

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HGM-MZ
Major Parts List with Part Numbers
Sampling Pump with
Connector 3015-5176
Rabbit Processor
Board
Hydrophobic Filter
07-1650
Battery
0204-
0020
Infrared Bench Replacement
Kit 3015-4572
Power Supply Board
3015-5149
Power
Entry
Board w
Fuse
Manifold Control Board
3015-5095
Main
Processor
Board
(Motherboar
d)
Replaceme
nt Fuses
(2)
0004-2620
Manifold Block w/ Purge
3015-5080
4 port manifold (not shown)
3015-5072
Plug in points for
optional dual 4-20
communications board
10 pin Ribbon
cable
3015-4258
12 pin
Ribbon
cable
Note: this sensor is
shown without the
YELLOW TAPE around

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Inside Cover View
Filters
3015-3125 Charcoal Filter Assembly with Fittings
3015-5931 Display PC
Board and Keypad PC
Board Kit
(With interconnecting
Ribbon Cable)
3015-5182 Ribbon Cable - Main
PCB to Keypad Board

Bacharach | THE MEASURABLE DIFFERENCE | New Kensington, PA, USA | Dublin, Ireland | Toronto, Canada | mybacharach.com
Figure 1
07-1650
Hydrophobic Filter
Figure 2
3015-2906
Line end filter only
Figure 3
3015-3420
Line End Filter Assembly
Figure 4

Bacharach | THE MEASURABLE DIFFERENCE | New Kensington, PA, USA | Dublin, Ireland | Toronto, Canada | mybacharach.com
Maintenance Check List
Item
Description
Repaired
Replaced
Y/N
Checked
Completed
Y/N
1
Visually inspect exterior of monitor for
damage and mounting integrity and Inspect
air sample tubing for damage and leakage
at termination points
2
With power off check all internal wiring
terminations and connections
3
Replace Charcoal purge filter ( Figure 1)
4
Replace Hydrophobic filter (figure2)
5
Replace line end filters (figure3)
6
Gas test zone with bump gas
7
Check IR voltages both Detector and
Digipot
8
Check sample pump pressures
9
Check HGM-RD remote display If
applicable
10
Take monitor in and out of service mode to
cause purge and pressure check and allow
it to cycle through all zones for final check
Notes,__________________________________________________
____________________________________________________________
____________________________________________________________
____________________________________________________________
____________________________________________________________
____________________________________________________________
____________
Work performed by,
_________________________________________

Bacharach | THE MEASURABLE DIFFERENCE | New Kensington, PA, USA | Dublin, Ireland | Toronto, Canada | mybacharach.com
Company Name
,___________________________________________
Date,___________________________________________________
__ Troubleshooting Guide
Deciphering the HGM MZ faults and numeric codes
Depending on the nature of thefault, the HGM-MZ mayor may not continue to operatenormally. Under
a non-critical fault condition, the HGM-MZ will continue to measure and log data, but some peripheral
functions may be compromised.
Under a critical fault condition, action is required for the HGM-MZ to operate normally. The table on the
following page lists the various fault conditions and explains what action should be taken to correct the
problem. The fault codes are cumulative, for example a code “4200” although not shown below is
actually individual codes 4000 “REZERO VOLT TOL” and a 200 “GAIN SET FAULT” combined to
indicate two faults registered at the same time.
Most common fault code is an “1800” which is a combination of a “1000” No flow on purge and an
“800” no flow on zone. A “1000” Fault will usually make an “800” because the zones will not flow as a
result.
Note:
Before any repairs or testing is done it is advisable to put the monitor into “Service Mode” and
then take it back out of service mode to get current Diagnostic information. (See last page for
directions)
Critical Faults
•NO FLOW ON ZONE (0800) –
1. Check for a blockage in the air sample line or at the line end filter.
2. Check for kinks or pinch points on e sample line
Note: Once the blockage has been cleared, the HGM-MZ will return to normal operation after
the zone has been sampled.
NOTE: This can take some several minutes since it is dependent upon how many zones
there are and their lengths. The HGM-MZ will clear the fault the next time it polls the effected
zone and the HGM-RD will return to normal operation the next time that it polls the HGM-MZ.

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•NO FLOW ON PURGE (1000) fault code –
1. Check the purge line for a blockage on the line end filter or charcoal purge filter.
2. Check the Hydrophobic filter for blockage of dirt or water. If it is water you must find and
eliminate its point of entry into the monitor.
3. Check to see if pump is running.
4. Verify the pressures on the Diagnostic screen; “DIAG” see detail DIAG screen below.
5. Verify that the length of the purge line and exhaust line combined do not exceed 500 feet
in length.
Monitor Diagnostic “DIAG” screen view
PUMP Trouble shooting Tips
1. If pressure and Vacuum are equal at a low number IE 10.8 to 11.6 PSIA. The pump
is OK but you don’t have any flow.
2. Check hydrophobic filter for dirt or water clog. If filter is clear then the problem could
be in the manifolds or manifold control board. Call Bacharach tech support for
assistance in trouble shooting the Manifold control board 724-334-5000.
DET IR Detector voltage Range
4.20 to 4.28 V
ZERO: IR Detector voltage; this
voltage should be the same as or
higher than The DET voltage.
If not it will generate a “100” ZERO
filter Fault
Length of zone being
sampled
Number of zone being
sampled
PRES: Pump pressure
relative to the zone being
measured. This number
varies based on the zone
length.
AMB: Ambient pressure
take during pressure check
(shows Sea level and will
vary with altitude).
VAC: stored vacuum
pressure number taken
during purge cycle shows
deepest pump vacuum.
Note:
PRES, VAC, and AMB, will never
be equal under normal sampling
conditions.
PRES will fluctuate relative to
zone length.
Note:
In the DIAG screen you will be
able to scroll through the zones by
pressing the right arrow key. You
can watch the pressure number to
see if any of the zones are
blocked.

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3. If Pressure, Vacuum, are equal to Ambient, 14.xx to (12.xx if you are in Denver).
Then there are three possibilities;
a) The pump is not pumping.
i. Note: the pump works on a volume / differential pressure and cannot
be verified by putting your finger over the end to see if it’s working.
b) There is a hose off of a connection
c) The Manifolds are stuck open; this could be a result of dirt inside the manifold
holding a valve open mechanically. It could also be a result of a failed manifold
control board, holding the solenoids on the manifolds open electrically. (see next
section on troubleshooting a Manifold control board failure)
Troubleshooting a suspected Manifold control board failure
If the fault code is an 800 or 1800 it could be due to a manifold control board failure.
After checking to make sure the pump is functioning properly the follow procedure
should be used to check the control board.
The symptoms are: during normal sampling mode the Pressure value and the ambient
value are equal or very close to equal at sea level they would be 14.xx PSIA. The
pressure is the live number with the Vacuum and Ambient values being stored for
reference during a purge and pressure check cycle. A good way to verify that the
manifold control board has failed electrically and is holding 2 or more solenoids open is
power down the monitor first, and then disconnect (unplug) all the solenoids from the
board. Then power the monitor up and If the Pressure goes to maximum Vacuum
(somewhere between 10.8 and 11.2) with all the manifolds disconnected then you know
it’s an electrical failure of the manifold control board. If the values stay equal at ambient
pressures then you know it’s a mechanical failure from dirt or moisture holding the
valves open. Do not reconnect the manifolds with the power on.
REZERO VOLT TOL (4000) –
1. The detector output voltage is out of tolerance. (see HGMMZ voltage adjustment
in the annual maintenance guide or the HGMMZ voltage adjustment bulletin)
OVER RANGE DETECTED (2000) –
1. This indicates the measured concentration on one or more zones exceeds the
measurement range.
2. Has the monitor been exposed to pure refrigerant? If not check the sensor
voltage range.

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ZERO FILTER FAULT (0100) –
1. Indicates contamination in the purge air, could be caused by dirt, water or
refrigerant in the charcoal purge filter. The charcoal filter may need to be
changed.
2. Check to make sure the purge line has a filter on the end, “line end filter p/n
3015-3420”
3. Check to see where the purge air is coming from, the purge air must be from a
clean dry source.
GAIN SET FAULT (0200) –
1. Indicates sensor gain (digipot) is outside acceptable range. (see HGMMZ voltage
adjustment bulletin)
2. If the gain set fault keeps showing up it could be an indicator of a failing IR
sensor.
LOOP FAULT (0010) –
1. This would only be displayed if the dual 4-20 ma dc option card was installed and
one or both current loops are open. (unconnected to load or without shorting
jumpers)
2. Check the wiring to load/monitoring circuit on both 4-20 mA loops to make sure of the
connections or install shorting jumpers.
CONFIG FAULT (0080) –
1. There is an error in HGM Setup Screen in the Number Zones Installed field. The
number of zones installed is equal to the number of hoses connections on the side;
Note the number of Zones being used.
BUMP GAS TESTING
BUMP TESTS: Gas test (or “bump test”) each zone using the bump gas method
described below to ensure that the monitor is operating properly, the alarms operate, and
that each zone’s gas path is clear.
a. This procedure uses “bump gas” (dilurothane) as an inexpensive test gas.
Virtually any brand of keyboard cleaner or “canned air” (readily available at most
computer and variety stores) contains this refrigerant and is sufficient to perform a
bump test.

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b. Power up the HGM-MZ monitor. The green LED on the monitor will blink until the
warm-up cycle is complete.
c. Locate and identify the zone to be checked.
d. Either put the target zone on hold for continuous operation, or wait until the
monitor is polling that specific zone. (Putting the zone on hold is the preferred
method)
NOTE: To place a zone on hold for testing, start at the Normal Operating
Screen. Using the arrow key, move the cursor to the right to cover the list of
zones. Then, using the up and down arrow keys, select the zone to be put in
hold mode. When you have the cursor on the target zone, press enter until
you hear a beep (about 1 second). The zone will remain on hold for 15
minutes or until you release it using the same selection method above to
release.
e. Have someone view the information at the monitor for the zone to be tested, and
at the same time have a technician dispense the bump gas. The technician
should release a 2-second burst of gas directed at the test zone pickup while the
monitor is polling that zone.
f. After a short delay, the monitor will indicate the presence of gas on that zone.
The PPM reading will vary as this is not a regulated gas application.
g. If no refrigerant is detected by the monitor, the tubing needs to be inspected for
an open or blocked pathway. If the tubing was pinched or plugged, the monitor
will show a flow fault (indicating a flow-related problem) in addition to no
refrigerant being detected for that zone.
FINAL CHECK: Take the monitor in and out of service mode. This will cause a purge and
pressure check. It will also allow the monitor to cycle through all zones for a final check.
SAMPLING SCREEN: Finish by putting the monitor into service by returning the display to the
main sampling screen.
SERVICE MODE
To enter service mode:
From the main sampling screen (figure 1) press enter two times that will take
you to the SETUP screen (figure 2) then move the cursor to the Service Mode
entry box, then press enter, it will now say (service mode confirm), press enter
again, it will now say, (service mode quit), press enter again, it will now say
(service confirm quit), press enter again and if you did it correctly it will say
(service mode entry) again.

Bacharach | THE MEASURABLE DIFFERENCE | New Kensington, PA, USA | Dublin, Ireland | Toronto, Canada | mybacharach.com