Bob and Tim have been tuning up a system with an orifice metering device for the correct evaporator charge, when Bob said, “There is another verse to tuning up a system, and it’s called subcooling.”
In this month’s troubleshooting situation, our customer has called to say that the roof-mounted gas pack on their 1,500-square-foot home isn’t keeping them cool. Their specific description of the problem is that they “can’t feel any air” coming from the supply registers.
Bob and Tim were on their way to a no cooling call at a residence. They were pretty sure that it was a low refrigerant call. Bob said, “I hope that we can put the last lesson into practical practice. We have gone to a great deal of trouble to understand superheat.”
Loose electrical connections to motor terminals can cause voltage drop, overheating, and a chance of fire. For three-phase motors, a loose connection can cause single phasing — which will damage the motor.
Bob and Tim were in the company conference room where Bob is set to give Tim some extra training at Tim’s suggestion. Bob said, “Tim, you asked for more explanation of what superheat is. This is not a very simple topic. It will take a couple of meetings to go into detail about it.”
In this month’s troubleshooting situation, the customer hasn’t called because their HVAC system has stopped cooling. You’re there because they’ve requested a preventive maintenance check of the five-year-old equipment to determine if there are any potential problems that would affect the system performance in the future.
Bob and Tim were driving to the job they left yesterday and talking over what needs to be done today, when Tim asked, “How are we going to move the condensing unit we disconnected to the new location so we can connect it to the system where we disconnected the defective condensing unit? You said you had a plan.”
Bob and Tim were on their way to a no cooling call at a commercial building location. This is a large manufacturing plant that has a number of installations. They arrive and talk to the maintenance man and he tells them which unit it is and goes with them to the area that the unit serves. It is a large room served by a 20-ton split system.
In this month’s troubleshooting problem we have a homeowner who has attempted to repair his own equipment, and he has replaced two components. The original symptom of the split system sitting dead still exists.
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