If the coil is filthy, clean down with a tube pipe on the coil just, but do not make use of a high-pressure pipe or stress washer as this could trigger damage to the fins and the device. http://211crisisresponse.com/__media__/js/netsoltrademark.php?d=New-kunitachi-kings.jp.net%2F%3Fwptouch_switch%3Ddesktop%26redirect%3Dhttps%3A%2F%2Fplaistowairconditioning.co.uk%2Fair-conditioning-repair.html