In the last post, we looked at the issue of air in the refrigerant system and how important it is to get the air and moisture out during the installation or service process. Evacuation of the refrigerant circuit has always been a bit of a challenge for several reasons. Following are a few of the most common:
Vacuum pump efficiency and effectiveness due to lack of pump maintenance, specifically changing the oil.
- The solution to this dilemma is simple. Change the oil, ideally every time the pump is used.
- The oil should most definitely be changed anytime the pump is used on a system with known contamination problems.
Connection leaks between the refrigerant gauges, the vacuum pump and the refrigerant system.
- Choices available among digital refrigerant manifolds today simplify that connection challenge with built-in micron vacuum level display capability.
- Some manufactures also offer the ability to connect to the refrigerant system in a manner that substantially reduces the number of connections requirements for the evacuation process.
- Many manufactures offer wireless connectivity that deliver vacuum readings, refrigerant pressures and real-time superheat and subcooling values right to your smart phone.
- The price point on this type of equipment is competitive and the technology offers you a very quick return on your investment when time and labor savings are considered.
- The cheapest test tool or instrument in many situations is not your best investment, so take time to investigate the benefits and weaknesses between similar test products.
Not having an adequate means of monitoring vacuum progress.
- See the comments above.
Not enough time.
We’ve all been there. You’re under the gun to get to the next job, or the boss is breathing down your back about taking too long. Professional HVAC technicians (and their bosses) know that there is no specific amount of time within which an effective vacuum can be achieved. Evacuation is dependent on several variables, a few of which are:
- Outdoor temperature
- Refrigerant type
- The amount of moisture in the system
I met an HVAC contractor in Denver several years ago who has the right philosophy regarding this issue. His position is: “I can pay my techs to do it right or I can pay them to do it over. Even more importantly, there is no quicker way to erode the loyalty of our customers than to put them in a situation where they will question our commitment to their well being.”
I can’t add anything to that.