Some Modifications Can Make HVAC Systems More Serviceable
Make sure it makes sense and doesn't change the design of the system
A common saying in the trades is “work smarter, not harder.” This is a good motto for refrigeration service technicians. When installing or repairing a refrigeration system, technicians should look for opportunities to slightly modify the system (without changing its design) to make it more serviceable.
Units shipped from the factory are not always built or designed with extra features to make them easy to service. If there is a way to make a system more service-friendly during an installation or major repair, technicians should do it — as long as the modification makes sense economically and does not change the design of the system.
For example, on some larger systems, adding access ports at different locations may be beneficial in the long run. An access port on the liquid line ahead of the expansion valve would allow for a more accurate measuring of subcooling at that location. Also, if the system has a receiver — which, when the “king” valve is front-seated, the hose connection is to the tank and not the liquid line — an additional access port in the liquid line could make adding liquid refrigerant to the system faster and easier. This can be a tremendous help when working on systems using a refrigerant blend.
Adding an access port to the outlet of the evaporator may make superheat measurements easier and a little more accurate too. Many times, when we measure the refrigerant’s superheat value leaving the evaporator, we are forced to measure the refrigerant’s pressure at the inlet of the compressor. This is generally not an issue, as a well-designed and -installed system should have a minimum pressure between the outlet of the evaporator and inlet of the compressor. But we do not always work on well-designed and -installed systems, so there may be a significant pressure drop across the suction line.
Another simple modification could be to extend the piping on existing or newly added access ports. This may make it easier to attach gauges to the system in the future.
Depending on the size of the system and the frequency of maintenance required, adding a permanent suction and discharge gauge may be beneficial. This does add additional components and fittings that could leak over time, but it would make servicing the system much easier. It may also help prevent an accidental loss of refrigerant during a maintenance inspection. If while removing the service gauges during the inspection, the service valve or Schrader valve does not seat properly, it could cause the accidental loss of refrigerant.
On a larger system, or when cleaning up a contaminated system, installing a filter-drier bypass could save time and money. If the system needs several filter-drier change-outs, it would allow changing it without shutting down the system or having to pump it down.
There are many other ways a technician could make a system more serviceable. These slight modifications to the system could be beneficial to both a technician and the customer, as long as it makes sense and is not cost-prohibitive.
Publication date: 5/6/2019