Heartbeat loss

[imcobra]

I have a ICX7150 with two R510 APs. On repeated occasions (x10 a day), my access point downstairs and upstairs keeps disconnecting due to a heartbeat loss. 

{AP[2nd Floor AP@xxxxxxxxxxxx] joins with uptime [328220] s and last disconnected reason [Heartbeat Loss]}

{AP[1st Floor AP@xxxxxxxxxxxx] joins with uptime [293880] s and last disconnected reason [Heartbeat Loss]}

Regardless of using the Cat6 lines which are dropped through the ceiling, nor taking the AP and connecting directly to the switch with a new Cat6 cable. 

I've tried researching into extending the heartbeat timer, but search hasn't led to much. Please help! Thank you!