Service | Concept2


Incorrect or No Heart Rate

Symptom 1

Pairing the chest belt with the PM4 was successful, but the Confirm screen displays "0" or unrealistic heart rate values.


There are several potential reasons that a chest belt fails to transmit data to the PM4. Refer to the following:

  • Dead Battery in the Chest Belt—Review battery life expectancy information under How to Use; try replacing the battery.
  • Chest Belt is not "On"—Wet the chest belt contacts and place the chest belt around your torso, or wet hands and grasp one contact in each hand firmly once or twice to "wake up" the chest belt.
  • Reset the Chest Belt—If you have replaced the battery and the problem persists, try resetting the chest belt as follows:
    1. Remove the battery from the chest belt.
    2. Inspect the battery compartment to ensure it is clear of debris and that no signs of battery acid exist.
    3. Reinstall the battery upside down (positive side facing down).
    4. Remove the battery again and reinstall it normally.
  • Chest Belt is Defective or Broken—Contact Concept2 for assistance.
  • Chest Belt is not ANT Compatible—In order for the wireless heart rate feature to function with the PM4, the chest belt must be a Garmin ANT, Suunto ANT, or another ANT type belt. If yours is not, you must obtain the proper chest belt to make use of this function.
  • The PM4's Radio is Not Working—If you can, try a few other ANT type chest belts. If multiple chest belts do not work, the PM4 may not be operating properly. Contact Concept2 for assistance.
  • Radio Frequency (RF) Interference—Transmission of the heart rate data may be affected by RF interference. Ensure that any local WiFi equipment is not transmitting on channels that overlap ANT transmission channels. WiFi (802.11b and 802.11g) can be safely configured on channels 1–6; channels 7–14 may start to interfere with ANT Wireless. Consult your access point user manual for information on how to change the WiFi transmission channel.

Symptom 2

While rowing with a Suunto or Garmin chest belt, the heart rate values seem incorrect.


The only true method for measuring heart rate is by counting heart beats during a complete one minute period; the instant values displayed on the monitor or on a watch are estimates. A tolerance of +/- 5 beats is typical.

To determine whether valid heart rate values are being transmitted:

  1. Warm-up for at least five minutes.
  2. If the values continue to be erratic post warm-up, check the chest belt's positioning on your torso (visit How to Use for more information). You can also try wearing a cotton shirt or wetting your shirt. Synthetic shirts that rub or flap against the heart rate belt can cause static electricity and interfere with the heart rate monitor signal.

Symptom 3

On occasion, certain PM4s with the firmware version between 300 and 310 may stop showing heart rate values when used with a Garmin, Suunto, or ANT+ heart rate belt.


This may be due to a software glitch in the PM4. Users with the firmware version 300–310 should update to the latest firmware to resolve this issue. If the problem persists, contact Concept2 and ask to speak to a technician.