Articles by Jim Johnson
November 8, 2010
When the customer calls for service, he tells you that when things got very cold in the house, he disconnected the power supply to the unit, and then, after turning the 120-volt service switch back on, the operation seemed normal and the house got warm “for a day or so.” But the failure repeated.
September 6, 2010
In this troubleshooting situation, we have a customer who has called to say that their 12,000 Btu through-the-wall unit is “blowing cool air even though it’s set for heat.” The unit is a heat pump with a three-speed motor. It operates on 240 vac.
July 5, 2010
Your role in this month’s troubleshooting situation is as the follow-up technician on a problem that was made worse by the technician who preceded you. When the restaurant manager originally called for service, the complaint was that their small walk-in cooler “wasn’t keeping as cool as usual.” Now it’s “hardly cooling at all.”
May 10, 2010
This time around our problem centers on a split-system air conditioner. The condensing unit is 240-volt, single-phase, and the indoor air handler (which our customer is able to tell us is “blowing warm air”) consists of a standard gas furnace and an A-coil housed above the furnace plenum.
March 8, 2010
Your troubleshooting situation this time around relates to a walk-in refrigeration system in a busy restaurant that has experienced a compressor failure… specifically a mechanical failure. And it’s not the first time.
January 4, 2010
In this month’s troubleshooting situation we’re taking you to a modular classroom with a heating/cooling unit that employs resistance-type elements for the heating mode, and a direct expansion system for cooling. The complaint is that there is “very little cooling” being accomplished.
November 9, 2009
In this troubleshooting situation, we have a customer who is complaining about one of the bedrooms in their home, specifically that the gas furnace doesn’t warm the room properly. When you arrive, you find that the bedroom in question is the furthest from the furnace, and that the duct system is an extended plenum system.
September 7, 2009
This month’s problem piece of equipment is a soda vending machine. The complaint from the customer, who has positioned the unit outside their small motel, is that while the soda seems to be properly cooled during the middle of the day, there are times when the product is warmer than desired.
July 6, 2009
In this issue’s troubleshooting situation, the problem unit we’re facing is a reach-in refrigerator in a restaurant and the customer’s description of the problem is that they discovered spoiled food in the cabinet when they arrived early in the morning prior to opening.
May 4, 2009
This time around we have a customer who has called to say that it’s warmer than it should be in their home. When you arrive you find a nine-year-old package unit, and you determine in a short time that, electrically, everything is as it should be, which means that what you have is a unit that is running, but is not cooling enough.