ZebraStat ZS-2 User manual

ZebraStat
Operation Manual
™
Model: ZS-2
Analyzer, Remote Control, and
Multi-Mode Tester

Contents
Contents and Specifications ...........................2
Safety..............................................................3
Using the ZebraStat.....................................4-5
Continuity Mode ...........................................6-7
Analysis Mode.............................................8-9
ZebraStat Features...................................10-11
Activation Mode........................................12-13
Troubleshooting Electronic Boards..........14-15
Voltage Problems.....................................16-17
Circuit Protection...........................................18
Avoiding Problems........................................19
Warranty.........................................Back Cover
Maximum Input Voltage ...........................28 Volts
Overall Circuit Protection .....................5A. @ 24V
White Wire Circuit Protection ...............3A. @ 24V
Unit Size ...................................8”L x 5”W x 2.25”H
Specifications
2
Maximum Current Through Unit................5 Amps
Unit Weight .................................................18 oz.
Warranty ....................One-Year Limited Warranty

3
Safety
Please read all of these instructions before
using your Zebra-Stat. Information provided will
protect you, your customers, and their property
from harm or damage. Understanding the
proper use of this tool will also help you to make
more accurate diagnosis on the equipment that
you are servicing.
ŸNEVER connect any lead to (nor allow
any unconnected lead to touch) line
voltage, or any voltage higher than 28
Volts.
ŸDo not perform an activation that a normal
thermostat could not perform, such as
c a l l i n g f o r h e a t i n g and c o o l i n g
simultaneously. (Unless you are servicing a
heat pump.)
ŸIf the equipment requires it, respect staging
precedence. (i.e.: Do not turn on stage two if
stage one is not already activated.)
ŸDo not allow your ZebraStat to get wet. If it
does get wet; dry it thoroughly before using.

4Using the ZebraStat
To use your ZebraStat, follow these steps:
1.) Decide the . Mode
2.) appropriate leads.Hook up
3.) Mode & Component switches.Manipulate
4.) the LED’s and equipment tested.Observe
Explanation of steps:
1.) Mode: The ZebraStat operates in three
different modes. You can easily leave it hooked
up and use all three modes on the same
equipment as needed.
ŸContinuity - This mode tests that the wires
that y o u connect to electri c a lly ‘go
somewhere.’ For instance, the wire that you
connect to the FAN lead normally goes
through a fan relay, and the continuity mode
will tell you if there is a continuous circuit
through that relay on the other end of the
equipment’s wire.
ŸAnalyze - This mode simply displays the
power flowing though the circuits that your
leads are connected to. Red LED’s tell you
power is available in the equipment. Yellow
LED’s light when the thermostat is calling for
heating, cooling, fan, or reversing valve.

5
ŸActivate - This mode is like having a remote-
control thermostat. Technicians often use it
when the thermostat is not easily accessible:
when making a diagnosis or repair to a unit in
an attic, basement, roof, or new construction
where the thermostat hasn’t been installed
yet.
2.) Hook-Up - Start with the mode switch in the
ANALYZE position and have all component
switches OFF. The hookup of the ZebraStat’s
leads is the same for all modes. Connect the
leads to their respective wires at the equipment.
(Common uses of wire colors are listed below
the component switches. However, you can use
any of the wires to test any other 24V function,
like ‘Emergency Heat.’) Connect the red and
blue leads to the equipment’s 24V power,
observing polarity. All modes, except
ANALYZE, require that all thermostat functions
be OFF.
3.) & 4.) Manipulate Controls & Observe
LED’s & Equipment. See the following
sections (Continuity, Analysis, or Activation) for
the proper steps to follow next.

6Continuity Mode
Continuity Mode tests that the wires your
ZebraStat’s leads are connected to ‘go
somewhere’ electrically. For instance, the wire
that you connected the FAN lead to normally
goes through a fan relay. Using this mode will
tell you if there is a continuous circuit through
that relay on the other end of the wire.
1.) Turn all thermostat functions to OFF.
2.) Turn all the ZebraStat’s component switches
to OFF, and put the Mode Switch in the
ANALYZE position.
3.) Attach the ZebraStat’s component leads to
the appropriate equipment wires, then
attach the red and blue power leads to the
equipment’s 24VAC hot and common wires,
observing polarity.
4.) Verify that no yellow LED’s are lit before
proceeding. If they are, re-check thermostat
for ON (or wiring for shorts) before
continuing.

7
Caution: The continuity mode passes a very
small amount of current to ‘test’ each of the
circuits that it is connected to. As more modern
equipment uses computer-type processing
boards to control equipment, some may be
designed that have functions that might be
activated by the ZebraStat ’s tiny (about 7 ’
milliamps) of current to test the different circuits.
Be aware that some circuits might possibly be
activated while testing in Continuity Mode.
5.) Place the mode switch to the continuity
position. Green LED’s should illuminate
under each component being tested. No
light probably indicates an incomplete
circuit. A yellow LED indicates the
component under t e s t is currently
ACTIVATED; the LED will change back to
green when activation is removed. Control
boards on some new variable speed units
may give false positive indications.

8Analysis Mode
Analysis Mode simply displays any control
power that is being sent to the circuits that your
leads are connected to. This mode is often used
by a tech to isolate the general area of a
problem. Red LED’s will indicate the level of AC
power available at the equipment. Yellow LEDs
will illuminate on each circuit that is currently
energized.
For instance, you turned the FAN switch on at
the thermostat, but the fan does not start.
Observing a lit yellow LED in the FAN section of
the ZebraStat connected to the equipment
would tell you that the signal is getting to the
equipment (suggesting a problem inside the
equipment.) If the corresponding LED was NOT
lit, (the signal was not getting to the equipment)
it suggests that the problem may be in the
thermostat or its associated wiring.
1.) Turn all of the ZebraStat component
switches to OFF, and put the Mode Switch
in the ANALYZE position.

9
2.) Attach the ZebraStat’s leads to the
appropriate equipment wires, then attach
the red and blue power leads to the
equipment’s 24VAC hot and common wires,
observing polarity.
3.) Notice which yellow LED’s are illuminated
under their component switches. (All of the
component switches must be OFF.) These
LED’s indicate which circuits are currently
receiving power. Technicians often use this
feature to troubleshoot: (a) cross-wired
thermostat wires (for instance, if the
condensing unit starts when the fan switch is
activated on the thermostat) or; (b) shorted
thermostat wires (for instance, if the two
cooling stages start simultaneously when
only one is being calle d for ; or a
continuously operating fan.) Note: many
thermostats pre-connect FAN & COOL
leads when set to ‘cool’ mode, etc.
4.) Manipulate the thermostat’s switches and
observe the results on the ZebraStat to
verify that all functions are working
properly.

10 ZebraStat Features
Mode Switch
Upper Trip LED (Red)
Voltage Monitor
Lower Trip LED
Instruction Manual
(QR Code)
Lead Compartment
Magnet
(On Back)
Quick Reference
ZebraStat Webpage

11
Model: ZS-2
Hanging Hook
Component Switches
Component Displays
Continuity LED’s
(6-Green)
Activation LED’s
(6-Yellow)
Wire Color Codes
Leads
Velcro Strap

12 Activation Mode
Activation mode is similar to having a remote
controlled thermostat. Technicians often use
this mode when the thermostat is not easily
accessible, as in when making a diagnosis or
repair to equipment in an attic, basement, on a
roof, or other location remote from the area
where the thermostat is located.
1.) Turn all thermostat functions to OFF.
2.) Turn all of the ZebraStat’s component
switches to OFF, and put the mode switch in
the ANALYZE position.
3.) Attach the ZebraStat’s leads to the
appropriate equipment wires, then attach
the red and blue leads to the equipment’s
24VAC hot and common wires, observing
polarity.
4.) Verify that no yellow LED’s are lit before
proceeding. If any are, recheck thermostat
for ON (or wiring for shorts) before
continuing.

13
6.) Turn on component switches as appropriate.
Use care to activate components logically.
For instance, do not turn on BOTH a heating
and a cooling stage at the same time. Like-
wise, you usually turn on FAN when a cooling
stage is active. Finally, respect the sequence
of stages; don’t activate stage 2 (cooling or
heating) unless stage 1 is active.
Note: So m e systems may have other
components, like ‘Emergency Heat’ that you
may test. You can use any of the four ‘stage’
wires, (HEAT 1 & 2, etc.) to test these
components.
Caution: Remote activation can surprise
another technician working elsewhere on
related equipme nt. Communi cate your
intentions to anyone else involved. For
instance, when remotely activating the cooling
stages of a system; you don’t want to start a fan
or co m p r e s so r tha t som e o n e ma y b e
inspecting.
5.) Turn the Mode Switch to ACTIVATE.

14 Troubleshooting
Electronic Boards
A blown fuse on an electronic control board
presents special challenges. Rather than just
replacing the fuse (and possibly watch it
‘blow’ again) the ZebraStat offers a diagnostic
alternative. The white wire (the HEAT1 circuit)
has a special function built into it. Between
the red and white wires is a low-amp, auto-
reset, solid-state ‘circuit breaker.’ This circuit
breaker is set to ‘trip’ at 3 Amps, providing a
safe alternative to repeatedly replacing fuses
while looking for the cause.
Here’s how it works: Remove the blown fuse.
Attach the red and white leads of the
ZebraStat to the board or fuse-holder where
the fuse was. No other leads should be
attached for this mode. Turn the mode switch
to ACTIVATE and turn ON the HEAT1
component switch. All other component
switches should remain off. Now, the
ZebraStat’s circuits are acting as a ‘circuit
breaker’ with a rating of 3 Amps.

15
If the current flowing into the ZebraStat through
these two wires should exceed 3 Amps, the
breaker will ‘trip’, and the lower Trip LED will
light. The breaker will stay in this ‘tripped’
condition until the power is removed from one of
the leads for about 15 seconds. (Some
electronic thermostats may start a set/reset
cycle as they lose power and drop out.)
A typical problem causing a fuse to blow on one
of these boards is a shorted thermostat wire.
Diagnosing which wire is accomplished much
easier with the ZebraStat. Hook up the
ZebraStat as described above. When the
ZebraStat’s breaker trips, remove power to the
system for 15 seconds. While the power is off
remove one thermostat wire at a time from the
control board, turning on the power again after
each disconnection. When the trip LED does
not light up after removing a wire - the suspect
circuit has been found. If all external low voltage
control wires are removed, and the trip LED still
lights, it’s time to suspect that the board itself
may have a problem.

16 Voltage Problems
Voltage problems in a system are frequently
overlooked, but are very easy to find. For
instance, many technicians don’t compare the
current draw on the contactors when replacing
one. In most cases there won’t be a problem,
but if the transformer is already close to it’s
output capacity, and the new contactor requires
a higher current level to close, intermittent
problems are likely to arise, especially if the line
voltage drops a few percent because of high
demand, for instance, on a hot afternoon.
The ZebraStat has a built-in voltage monitor
section that makes it easy to tell if the voltage
being supplied at the red and blue leads is
adequate. (These voltages could easily be
determined with a voltmeter, of course; but
many technicians do not check for low-voltage
levels while under load, even though they
could.)
Getting used to glancing at the Voltage section
of the ZebraStat may help you detect some of
these problems before they actually cause a
fault.

There are three red LED’s in the voltage
section: ON, ??, and OK. The ON LED will light
when the voltage applied to the power input
leads is at least 8 volts. The ?? (Questionable)
LED glows about half-brightness at 19.5 volts,
and full-brightness at 20.5 volts. The OK LED
glows about half-brightness at 21.5 volts, and is
fully bright at 23 volts.
Any time that you are using the ZebraStat and
notice that the OK LED isn’t fully lit, you may
want to check the voltage level at the
component that is farthest away from the
system transformer while under load. (The
voltage drop from the wires will be greatest
there.) If the OK LED isn’t glowing at least half-
brightness, there is the potential that higher
temperatures (higher wire resistance) and
lower line voltage (due to high demand) may
cause that component to not be able to close
fully, or, in the case of reversing valve, not be
able to change positions. A higher-rated
transformer may be called for, or larger wiring.
17

18 Circuit Protection
Your ZebraStat provides circuit protection in two
ways. Each uses a solid-state, automatically-
resetting circuit breaker device. The white test
lead is protected with a 3 Amp device. You can
l e a r n m o r e a b o u t i t ’ s u s e i n t h e
“Troubleshooting Electronic Boards” section.
The second device provides an overall
protection for the ZebraStat. It is rated at
approximately 5 Amps at 28 Volts. (150VA)
If you inadvertently hook up the ZebraStat’s
power input leads using an incorrect ‘polarity’
and attempt to use the Activation mode, or if you
allow a loose ‘hot’ lead to touch ground, you will
probably ‘trip’ this circuit protection shutting
down the ZebraStat, and turning on the red
TRIP LED. The unit will remain in the tripped
condition until you remove all power to the unit
for about 15 seconds. Before reconnecting,
discover and correct the condition that
caused the trip.
This protection device is not meant to protect
the unit from higher voltages than 28 Volts.

19
Avoiding Problems & Help
1.) The “power-in” wires (RED & BLUE) ARE
POLARIZED, even though it’s an AC circuit!
The RED lead must connect to the equipment’s
HOT wire (usually red), and the BLUE lead must
connect to the equipment’s COMMON wire
(usually brown or blue.) REVERSING THESE
LEADS CAN CAUSE THE ZebraStat’s
CIRCUIT BREAKER TO TRIP.
2.) If you are getting a strange LED indication in
either CONTINUITY or ANALYZE modes, it
could be caused by having one of the
ZebraStat’s component switches ON. Leave all
six switches OFF for testing in either of these
two modes.
3.) In the CONTINUITY or ACTIVATE modes, all
thermostat switches should be OFF, and it must
not be calling for any heating or cooling.
Strange LED indications may appear on the
ZebraStat if all thermostat functions are not
completely ‘OFF.’
4.) Some thermostats internally connect their
‘G’ and ‘Y’ terminals when in ‘Auto Fan.’ (This
will be noticed in the CONTINUITY or
ANALYZE Modes.)
5.) Some thermostats may activate the
reversing valve as soon as they are switched
into ‘Heat’ or ‘Cool’ (CONTINUITY or ANALYZE
Modes)

One-Year Limited Warranty
For a period of one year from the original end-
user’s date of purchase, Zebra HVAC
warrants that this tool is without
manufacturing defects. Should you encounter
any problems, please contact us and we will
attempt to resolve your problem as quickly as
possible. This resolution may include
replacement, exchange, or repair of a
defective tool; at our option. This warranty
does not apply to tools that have been
exposed to: voltages and/or currents that are
higher than those specified in this manual;
abuse or rough handling; or damage from
moisture or chemicals. Out-of-warranty
repairs are available for a nominal charge
plus shipping. Please contact us for an RMA
(return merchandise authorization) before
returning a tool for repair.
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