Set page limit in magento

You need to add the following line

$_productCollection->clear()
                   ->setPageSize(100)
                   ->load();


your code looks like this

<?php
    $_productCollection=$this->getLoadedProductCollection();
    $_productCollection->clear()
                   ->setPageSize(100)
                   ->load();
    $_helper = $this->helper('catalog/output');
?>

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