When teaching students how to use and read a tape measure for the first time, I have a go-to set of items to facilitate the training. I use 13 pieces of wood with 26 measurements labeled A-Z. Each piece has two letters, one for each dimension to be measured. I then give each student a fraction layout sheet for an inch and another sheet that they can write their answers on for each letter measured, A through Z. I explain the 1/2", 1/4", 1/8" and 1/16" fractions, full one inch measurements, and...

If you remove the vapor access port cap on a running air conditioning system, the low temperature brass on the inside of the port will condense water vapor from the air surrounding the port directly onto the port. This is because the air surrounding the port is often below the dew point. Don't remove the port cap until you are immediately ready to connect the gauge. Don't even connect the gauge unless you suspect a problem with the refrigerant charge level. We want to reduce the chances of...

After servicing or adding refrigerant to an air conditioning system, add locking caps to the service ports if the system is in an accessible area. This reduces the chance of someone tampering with the refrigerant charge. The IMC code that requires this may or may not be adopted/enforced by your local municipality. However, it is a really good idea to do so to keep everyone safe and to keep the refrigerant charge intact. IMC Code 1101.10: " Refrigerant circuit access ports located outdoors...