This way it should work;  note i changed float to 'reserve' and added 'threshold' to the code


// Fetch locked balance from transactions
$dLockedBalance = $transaction->getLockedBalance();
$log->logDebug("The Locked Wallet Balance for Users is: " .$dLockedBalance. "\n");
// Fetch Final Wallet Balance after Transfer
$aFloat = $dLockedBalance + $config['coldwallet']['reserve'];
$aThreshold = $config['coldwallet']['threshold'];

$log->logDebug("The Locked Wallet Balance & Float amounts to: " .$aFloat. "\n");

// Send Liquid Balance
$send = $dBalance - $aFloat ;
$log->logInfo("Final Sending Amount is : " .$send. "\n");

if($send > $aThreshold){
        $bitcoin->query('sendtoaddress','. $config['coldwallet']['address'] .', $send);
}
else{
        $log->logInfo("Final Sending Amount Not Exceed threshold : " .$send. "\n");
}