Have an aerofiner 11 fitted on a cat 12H grader. On cold mornings it's dumping out of the airdryer until it empties the whole airsupply when the handbrake's released. As soon as the machine is warmed up all runs fine. Have replaced the dump valves on the aerofiner and the heater. Anyone else had issues like this with a remedy? Anyone have full diagrams available as am looking at disconnecting the aerofiner.
When was the last time the dessicant cartridge was changed..? Is it a Cat dryer or has someone installed it as an aftermarket..? If it's Cat what is your machine Serial Number..? Edit: Another thought. Have you had the feed line off the air compressor and is it full of oily residue..?
Dessicant was changed about a week ago, dump valve got a new seal kit put in about the same time, it's been installed as an after market (an aerofinner 11). Haven't looked at the feed line yet but will do tomorrow. The system drops air far too regularly for the first half an hour until it's fully warmed up and then it runs fine. It sometimes is taking up to 10 minutes for the brakes to release on some days and on other days it'll release first go. Have asked lots of fitters etc and no one has any solutions to offer. Have ordered a new heater unit in case it's faulty. Am wondering exactly what regulates the dump valve, is it an electrical switch or something else as it appears the dump valve isn't working correctly.
The only reason for the heater is to stop any accumulated moisture in the bottom of the dryer from freezing. I wouldn't have thought you would suffer from that problem in NSW ...... The dryer dump valve is actuated by an air pressure signal from the compressor governor when it cuts out. For the dryer to purge correctly the compressor has to cut out. Have you checked the compressor governor for correct functioning and cut-in/cut-out pressure..? Maybe to get the dryer to crank up correctly the engine needs to be started and left for the air compressor to go through a complete cut-out cycle before the parking brake is released..? Also do you have any air leaks on the system that you can hear with the air built up to maximum working pressure and the engine switched off..? Are you accumulating any liquid in the air tanks at all..?