Citizen CHU503 Digital Blood Pressure Monitor Instruction Manual

Overview

The CHU503 Digital Blood Pressure Monitor is an automatic upper-arm monitor designed for personal blood pressure checks at home under the guidance of a physician. It uses the oscillometric method to measure systolic pressure, diastolic pressure, and pulse rate in one operation.

The monitor includes automatic inflation, automatic deflation, a large digital display, date and time recording, memory recall, and indicators for blood pressure classification, body movement, and irregular heartbeat. It is intended for single measurements rather than automatic cycling measurements.

Specifications

• Model: CHU503
• Measurement method: Oscillometric
• Measurement location: Upper arm
• Standard cuff: SCN-003 soft cuff for arm circumferences from 22.0 to 32.0 cm
• Optional large cuff: SCL-005 for arm circumferences from 32.0 to 42.0 cm
• Pressure measurement range: 0 to 280 mmHg
• Pulse measurement range: 40 to 180 beats per minute
• Pressure accuracy: ±3 mmHg
• Pulse accuracy: ±5% of the displayed reading
• Power: Four AA batteries
• Optional power adapter: AC-230CZ dedicated adapter
• Rated electrical input: 6 V DC, 3 W
• Memory capacity: 90 measurement results
• Average reading: Average of the last three stored measurements
• Main unit dimensions: Approximately 145 × 76 × 96 mm
• Main unit weight: Approximately 290 g without batteries
• Cuff dimensions: Approximately 144 × 492 mm
• Operating temperature: 10°C to 40°C
• Operating humidity: 30% to 85% relative humidity
• Storage temperature: -20°C to 60°C
• Storage humidity: 10% to 95% relative humidity
• Automatic power-off time: Approximately three minutes

Detailed Description

The monitor detects pressure oscillations in the arm cuff while the cuff inflates and deflates. It then calculates the systolic blood pressure, diastolic blood pressure, and pulse rate and shows the results on the LCD.

The main unit has an air hose socket, display, battery compartment, date and time setting switch, adjustment switch, memory switch, and START/STOP switch. The cuff has an air hose, blue positioning marker, metal hoop, and hook-and-loop fastening area.

The display can show systolic pressure, diastolic pressure, pulse, date, time, battery status, memory data, the three-reading average, blood pressure classification, body movement, and irregular-heartbeat indications.

The standard cuff is suitable for a 22 to 32 cm arm. If the arm circumference is larger, use the optional large cuff designed for 32 to 42 cm. Selecting the correct cuff size is necessary for a meaningful reading.

Safety

• Use the CHU503 only for blood pressure measurement. It is not a diagnostic device and does not replace medical advice.
• Do not change prescribed medication based on a home reading without consulting a physician.
• People with heart disease, high blood pressure, circulation problems, a pacemaker, weak pulse, or an irregular heartbeat should ask a physician whether the monitor is suitable.
• Do not use the cuff on an injured arm, an arm receiving an intravenous drip, or an arm being used for a blood transfusion.
• Do not use the monitor on infants or newborns.
• Do not use the monitor near flammable anesthetic gases or in oxygen-enriched environments.
• Keep mobile phones away from the monitor during use because electromagnetic interference may cause malfunction.
• Stop the measurement immediately if the cuff pressure feels abnormal or the measurement causes discomfort. Press START/STOP, remove the cuff, or disconnect the air hose as appropriate.
• Repeated inflation or measurements without a sufficient interval may cause congestion or swelling. Wait about one minute between measurements.
• Do not wrap the cuff so tightly that it causes pain. Correct tightness allows one finger to fit between the cuff and arm.
• Do not treat one result as a complete assessment of health. Record readings over time and discuss unusual patterns with a physician.

Setup

Package Contents

• CHU503 blood pressure monitor
• SCN-003 standard cuff
• Four AA batteries
• Instruction manual

The SCL-005 large cuff and AC-230CZ AC adapter are optional accessories.

Install the Batteries

1. Open the battery compartment by pressing down on the cover hook and pulling the cover toward you.
2. Insert four AA batteries, matching the positive and negative symbols inside the compartment.
3. Fit the cover tabs into the compartment recesses.
4. Press the cover down until the hook closes securely.

Do not mix alkaline and manganese batteries, and do not use rechargeable batteries. Replace all four batteries together when the low-battery symbol appears or the display remains blank. Changing the batteries does not erase stored readings, but the clock should be adjusted again.

Use the Optional AC Adapter

1. Insert the dedicated AC-230CZ adapter plug into the monitor’s adapter socket.
2. Plug the adapter into an indoor mains outlet in a dry location.
3. For extended adapter use, remove the batteries to reduce the risk of electrolyte leakage.
4. To disconnect the adapter, unplug it from the mains outlet first, then remove the plug from the monitor.

Keep the outlet and adapter area unobstructed so the power can be disconnected quickly in an emergency. If the adapter is disconnected while no batteries are installed, the date and time settings may be lost.

Set the Date and Time

1. Press and hold the date/time setting switch for about two seconds until the year begins flashing.
2. Use the adjustment switch to select the year, then press the date/time setting switch to confirm it.
3. Set and confirm the month, day, hour, and minutes in the same way.
4. Select either the 12-hour or 24-hour time format with the adjustment switch.
5. Press the date/time setting switch to save the format.

The year can be adjusted from 2013 through 2042. Setting the clock allows each stored measurement to retain its date and time.

Measuring Blood Pressure

Prepare for a Reading

• Use the bathroom before measuring and sit quietly for 10 to 15 minutes.
• Take five or six deep breaths and relax.
• Avoid measuring immediately after exercise, eating, bathing, drinking, smoking, or consuming coffee or tea.
• Use a room that is approximately 20°C. Avoid measurement in rooms below 10°C or above 40°C.
• Measure at the same time each day when possible.
• Remove heavy clothing from the measurement arm. The cuff may be placed over light underwear.

Attach the Cuff

1. Unroll the cuff and pass its end through the metal hoop so the hook-and-loop surface faces outward.
2. Connect the cuff’s air hose connector firmly to the air hose socket on the monitor.
3. Place the cuff around the bare upper arm with the blue marker facing the palm side.
4. Position the blue marker over the center of the arm.
5. Place the lower edge 1 to 2 cm above the elbow when using the standard cuff, or 2 to 3 cm above the elbow when using the large cuff.
6. Pull the cuff end outward and secure the hook-and-loop fastener.
7. Check the fit. One finger should slide readily between the cuff and arm.

Take the Measurement

1. Sit with the arm supported on a table and the cuff at heart level.
2. Relax the hand with the palm facing upward and keep the fingers slightly open.
3. Press START/STOP. The monitor automatically inflates the cuff.
4. Remain still and silent while the monitor measures.
5. Wait for the systolic pressure, diastolic pressure, and pulse values to appear.
6. Press START/STOP after the result appears, or allow the automatic power-off function to switch the monitor off.

If the monitor determines that inflation was insufficient, it may inflate again automatically. To stop a measurement at any time, press START/STOP. The cuff will deflate and the monitor will switch off.

For an expected systolic pressure above 200 mmHg, manual pressurization can be used by holding START/STOP until the pressure reaches approximately 40 mmHg above the expected systolic value. The maximum pressure is 280 mmHg.

Measurement Indicators

The body movement indicator appears when hand or arm movement causes a significant pressure change. Relax and repeat the measurement.

The irregular-heartbeat indicator appears when the detected heartbeat intervals vary substantially during measurement. Repeat the reading while relaxed. If this indicator appears frequently, consult a physician.

The hypertension classification indicator provides a visual classification based on the displayed blood pressure. It is a general reference and should not be used by itself to diagnose or treat a condition.

Accurate Measurement Tips

• Keep the center of the cuff at heart height throughout the reading.
• Do not talk, move, clench the hand, or shift position during measurement.
• Use the same arm and a similar posture for daily readings.
• The right and left arms can produce readings that differ by about 10 mmHg. Choose one arm for regular monitoring unless a physician advises otherwise.
• Measurements may be taken while reclining if the arm is straight, the palm faces upward, and the body remains relaxed.
• Do not leave the cuff inflated or wrapped around the arm for several minutes before starting a measurement.
• Wait about one minute before repeating a measurement.

Memory and Averages

The CHU503 stores up to 90 sets of blood pressure and pulse results. Stored records include the measurement date and time.

View Stored Results

1. Press the MEMORY switch once to display the average of the last three readings.
2. Press MEMORY again to display individual stored results.
3. Continue pressing MEMORY to move from the newest result toward older results.

The newest stored result is assigned data number 1. The average is not shown when fewer than three readings are available.

Delete Stored Results

1. Press and hold MEMORY.
2. While holding MEMORY, press and hold START/STOP for more than three seconds.
3. Release the controls after the display confirms that the stored data have been deleted.

Deleting the memory removes all stored readings rather than a single selected result.

Cleaning and Maintenance

• Store the monitor away from direct sunlight, temperatures above 60°C or below -20°C, relative humidity above 95%, and excessive dust.
• Keep the monitor and cuff away from children, pets, and pests.
• Remove the batteries when the monitor will not be used for an extended period.
• Do not drop the monitor or cuff, and protect them from impact, vibration, and excessive pressure.
• Do not disassemble the monitor or cuff.
• Do not sharply bend the cuff or air hose.
• For the monitor, use a cloth lightly moistened with neutral detergent, then wipe with a dry cloth.
• Clean the cuff with a moist cloth and avoid vigorous rubbing, which can cause air leakage.
• Prevent water from entering the air hose.
• Never use alcohol, thinner, or benzene on the monitor.
• The device is generally recommended for inspection about every two years to help verify proper operation and accuracy.

Dispose of the product and used batteries according to applicable local recycling and electronic-waste requirements. Do not place them with ordinary household waste where separate collection is required.

Troubleshooting

• The display stays blank: Install four new batteries and confirm that their positive and negative ends are oriented correctly. If using an adapter, check that the adapter plug is fully inserted.
• The monitor will not take a reading: Confirm that the cuff is connected, correctly positioned, and securely fastened. Remain still and try again.
• The cuff does not detect a pulse: Reattach the cuff with the blue marker centered on the arm and ensure that the cuff is neither too loose nor excessively tight.
• The cuff pressure feels excessive: Press START/STOP immediately to release the pressure. Remove the cuff and stop using the monitor if discomfort continues.
• The low-battery symbol appears: Replace all four batteries at the same time.
• The pulse is outside the measurement range: Relax and repeat the measurement. A pulse below 39 or above 181 beats per minute may prevent a valid result.
• Readings are unexpectedly high or low: Check cuff size, arm position, heart-level placement, room temperature, recent activity, and movement. Repeat the measurement after resting.
• The irregular-heartbeat or body-movement indicator appears: Stay quiet and still, then repeat the reading. Frequent irregular-heartbeat indications should be discussed with a physician.
• The clock is incorrect after battery replacement: Set the date and time again using the date/time setting controls.

Pros and Cons

Pros

• Automatic one-touch operation for straightforward home measurements.
• Upper-arm design with a standard cuff covering 22 to 32 cm arm circumferences.
• Stores up to 90 readings and calculates the average of the last three.
• Displays systolic pressure, diastolic pressure, and pulse together.
• Includes body movement, irregular-heartbeat, battery, and hypertension classification indicators.
• Can operate with batteries or the optional dedicated AC adapter.

Cons

• The standard cuff does not fit arms outside the 22 to 32 cm range.
• The large cuff and AC adapter are optional rather than included in the standard package.
• Readings can be affected by movement, posture, temperature, recent activity, and an incorrectly fitted cuff.
• The monitor is intended for personal monitoring and does not provide a medical diagnosis.