Bob and Tim have had a big day at work — it’s 3:30 in the afternoon, and they are done for the day. They’re having coffee at a local restaurant, talking about their careers when Tim asked a question, “What is a ton of refrigeration, and why is it called a ton?”
A thermostatic expansion valve (TXV) is designed to maintain a specific amount of superheat at the outlet of the evaporator. If the superheat value is too high or too low, the TXV may be the cause. However, before deciding the TXV is defective, all other system causes must first be investigated and ruled out.
Site Focuses on Equipment Servicing, Videos Provide Training on Heat Pumps
December 2, 2013
Technical Training Associates, an independent training firm in Tucson, Ariz., has established a new website at www.hvacrtroubleshooting.com that focuses on HVACR troubleshooting and equipment servicing. The company is also offering two videos on specific troubleshooting problems related to heat pumps.
Many service technicians experience service calls where the compressor has both a low head pressure and a high suction pressure. Often, the refrigeration equipment is still running, but the product temperature is suffering about 7-10°F.
In this month’s troubleshooting situation, we’re taking you to a school, but not to the equipment room of the main building. Instead, it’s a modular classroom (similar to a double-wide manufactured home) that is brand new, and employs a heating/cooling unit that mounts on one end of the building.
Interplay Energy develops 3-D interactive simulation training and testing applications. The company was approached about developing a companion program for the HVACR textbook, Refrigeration & Air Conditioning Technology. The end result is the new Delmar Online Training Simulation: HVAC from Interplay Energy.
In this month’s troubleshooting problem we have a customer who can only tell us that their heat pump “isn’t working” and “the temperature in the building isn’t right.” When you arrive, you confirm the system isn’t operating properly. The indoor fan motor is running normally, but the building temperature is far from the thermostat set-point.
Bob and Tim have been sent on a call to a house with no cooling. The system has just been installed and the construction crew has been having problems with startup. The system has a capillary tube metering device and Bob and Tim begin looking at what may be wrong.
Bob and Tim were on their way to a residence where the occupants said their unit runs all day long, but the space temperature rises to 82°F while the thermostat is set at 75°. The unit shuts off during the night and the temperature inside is 75° in the morning, but during the day it rises.
In this month’s troubleshooting problem, you have been called by a colleague who is relatively new to HVACR to assist in repairing a split system in a manufactured home. The original diagnosis regarding this unit that is sitting dead was that the PCB 3-amp fuse was blown, and when it was replaced, the new fuse also failed.