Bob and Tim have just repaired a leak on a 10-ton commercial air conditioning system and are ready to charge the unit. The system has a thermostatic expansion valve (TXV) for the evaporator.
Your role in this month’s troubleshooting situation is providing a second opinion on a failed compressor diagnosis. The customer’s complaint is that the unit isn’t cooling properly — the equipment is a heat pump package unit that is just past the warranty period for the compressor.
Bob and Tim just arrived at the house of a new customer. The customer explained to them that he just started up his air conditioner for the first time this spring. There was a warm spell, and the system didn’t work. As a matter of fact, it didn’t cool — the outdoor unit did not run at all. Bob explained to the customer that they would get started looking at the system and figure out what was going on.
In this month’s troubleshooting situation, you are dealing with a 4-ton split system, and the locale is a desert Southwest city. The customer in this case is the landlord, and they are working on the residence, getting it ready to rent after the departure of a long-term tenant. Their description of the problem is that the house “just won’t get comfortable.”
Bob and Tim are at lunch after tuning up an oil burner. When they arrived at the job the home was cold and the oil burner was burning erratically if burning at all. They gave the system a tune-up, started the furnace, and decided to take a lunch break while the furnace heated the house. Then they were going back to do a combustion check on the furnace to make sure that it was set up for the best combustion.
The gas laws… We all learned about them in school and promptly forgot all about them. I really think that we need to dig our books out, dust that information off, and work to understand and apply it.
Bob and Tim have arrived at a customer’s house that uses fuel oil for heat. This is a “no heat” call — the customer called first thing this morning and said that the oil furnace was not coming on, and the house was cold. When they arrived, they talked to the customer, and the customer said that he had made several tries to get the furnace to operate but with no luck.
It’s the middle of summer and your customer, who can’t provide you with any helpful information about the history of this situation since they just recently purchased the business, is complaining that the temperature inside their small convenience store won’t get comfortable whenever the outdoor temperature gets over 90°F.
Bob and Tim have responded to a service request where the customer is explaining that their heat pump is running all the time. The indicator light on their thermostat is lit most of the time, indicating the strip heat is on as well. The weather is cold today but has been warm some days and cold some days. It’s a very unusual heating season.
The first point to understand about refrigeration theory is that heat is energy, and it can be made to move. If enough heat is removed from a glass of water, the water will freeze to ice. When that heat is allowed to move back into the ice, the ice will melt.
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