I arrived to the front Roof top unit not cooling properly. Holly informed me that a different company had recently come out and replaced a fuse only. The system was still not cooling and they recommended the filters be replaced. We had previously agreed to replace the air filters. I was shown were both thermostats were located and noticed the same front RTU to have a blank thermostat. I proceeded onto the roof and changed the air filters. Once replaced I quickly did some tests on the electrical components inside the unit. Everything tested within range. I connected my gauges and replaced the fuse. The unit kicked on and I measured the pressures on both compressors. The liquid side of my gauges were reading in the mid 300’s this is considered extremely high for an R22 unit. I can imagine that before the air filters had been replaced the pressures were reading higher and potentially had triggered a high pressure switch. This high pressure switch can at time be faulty and cause the fuse t