Checked for other leaks with nitrogen, everything was OK. For example I had a unit with a leaking fitting so I replaced the fitting and the receiver dryer. I use my good equipment on these, Robinair 6 cfm dual stage pump and yellow jacket brute 2 gauges with a 3/8 vacuum line but it still takes a long time to reach 500 microns. On these jobs I can let the pump run longer. The other 50% of the calls are local and the unit is shut down for a period of time so it can be done properly. Whether I see it back or not time will tell. I do recommend that when the unit is down for service etc. Obviously they don't want to pay me for standing around. I advise the customer that the system should be drawn down to 500 but in most cases they let me run the pump for 1/2 an hour. I do field service which is 1 to 3 hours away. I do use a micron gauge on about 50% of the units I work on but here is the problem. This is great guys, please keep the information coming. That's based on about 5 different types of equipment that I have done for them. I have found with their units the high pressures are around 200 psi on average. I currently do work for the local Deere dealership so finding information for those is OK for now, until they start doing their own work. It was only about 40 degrees outside at the time. Who knows where the vent temp would be in the hotter temperatures. With that unit I put cardboard over the condenser to simulate a hot environment and charged it to 175 psi on the high side. I was working on the equipment in the cool weather and it was going down a couple thousand feet underground where to where it's hot. There was no information listed for the refrigerant charge. One of the challenges I had was on a piece of mining equipment that I worked on in the spring when it was cool out. Would this work for both expansion valves and orifice tubes? The other question I would have with this is that I would likely have to heat the tank on some units depending on the temperature. I would imagine it would be recommended to manually crank the compressor before starting the unit. I have never put liquid in the high side before. The problem is I have never seen the high gauge spike unless the fan is not working. I have been told by someone in the past to keep adding a quarter pound at a time until the high side gauge spikes and then remove a quarter pound. Here's my question, is there a better way to charge a system if you could not get the proper information on gauge readings or quantity of refrigerant specified by the manufacture? Most of us know that an under charge will affect oil flow and can be very damaging to compressor. I know an over charge is going to show high pressures, there is a the possibility that some of these units may be under charged. I have been charging to a high side pressure of about 225 psi on a hot day and around 200 when it is a little milder. My problem is with about 30% of the units that I work on. In some cases I am doing the work for a dealer who supplies me with the information. About 20% of those units have a sight glass which helps resolve the problem on those, to some extent. Approximately 70% of the time there is no tag showing the proper weight of refrigerant required. I have done automotive A/C for some time now but have started a business doing mobile work on heavy equipment.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |