ZebraStat ZS-2 Analyzer Remote Control and Multi-Mode Tester User Manual

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

Specifications

Maximum Input Voltage ………………………28 Volts
Maximum Current Through Unit…………….5 Amps
Overall Circuit Protection …………………5A. @ 24V
White Wire Circuit Protection ……………3A. @ 24V
Unit Size ……………………………..8″L x 5″W x 2.25″H
Unit Weight ………………………………………….18 oz.
Warranty ………………..One-Year Limited Warranty

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 a more accurate diagnosis on the equipment that you are servicing.

• NEVER connect any lead to (nor allow any unconnected lead to touch) line voltage, or any voltage higher than 28 Volts.
• Do not perform an activation that a normal thermostat could not perform, such as calling for heating and cooling simultaneously. (Unless you are servicing a heat pump.)
• If the equipment requires it, respect staging precedence. (i.e.: Do not turn on stage two if stage one is not already activated.)
• Do not allow your ZebraStet to get wet. If it does get wet; dry it thoroughly before using.

Using the ZebraStat

To use your ZebraStat, follow these steps:

1. Decide the Mode.
2. Hook up appropriate leads.
3. Manipulate Mode & Component switches.
4. Observe the LEDs and equipment tested.

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.

• Continuity – This mode tests that the wires that you connect to electrically `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.
• Analyze – This mode simply displays the power flowing through the circuits that your leads are connected to. Red LEDs tell you power is available in the equipment. Yellow LED’s light when the thermostat is calling for heating, cooling, fan, or reversing valve.
• Activate – 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.

Continuity 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 LEDs are lit before proceeding. If they are, re-check the thermostat for ON (or wiring for shorts) before continuing.
   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) 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 LEDs should illuminate under each component being tested. No light probably indicates an incomplete circuit. A yellow LED indicates the component under test is currently ACTIVATED; the LED will change back to green when the activation is removed. Control boards on some new variable speed units may give false positive indications.

Analysis Mode

Analysis Mode simply displays any controlling 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 LEDs will indicate the level of AC power available at the equipment. Yellow LEDs will illuminate 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.

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 LEDs are illuminated under their component switches. (All of the component switches must be OFF.) These LEDs 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 called for; or a continuously operating fan.) Note: many thermostats pre-connect FAN & COOL leads when set to `cool’ mode, etc.

4. Manipulate the thermostat switches and observe the results on the ZebraStat to verify that all functions are working properly.

ZebraStat Features

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 LEDs are lit before proceeding. If any are, recheck thermostat for ON (or wiring for shorts) before continuing.
   Caution: Remote activation can surprise another technician working elsewhere on related equipment. Communicate 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 compressor that someone may be inspecting.

5. Turn the Mode Switch to ACTIVATE.

6. Turn on component switches as appropriate. Use care to activate components logically. For instance, do not turn on BOTH heating and a cooling stage at the same time. Likewise, 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: Some systems may have other components, like Emergency Heat’ that you may test. You can use any of the fourstage’ wires, (HEAT 1 & 2, etc.) to test these components.

Troubleshooting Electronic Boards

A blown fuse on an electronic control board presents special challenges. Rather than just replacing the fuse (and possibly watching 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-statecircuit 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 acircuit breaker with a rating of 3 Amps.
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 thistripped’ 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 is 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.

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 its 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 LEDs 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 at 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.

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 learn more about its use in the “Troubleshooting Electronic Boards” section. The second device provides 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 loosehot’ lead to touch the 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.

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 components switched 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’ andY’ 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’ orCool’ (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 a 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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References

• Zebra Instruments
• Zebra Stat Support

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