Engineered Systems Magazine

Calibration instruments: Good Day Tools

June 13, 2012

Good-Day-Tools-01312-body.jpgNew product advances the use of pressure switches.

Good Day Tools has started production of its Draft Simulator, which is designed to calibrate and test adjustable and factory-set pressure switches, procedures that until now involved crude tests such as sucking and blowing on a tube.The instrument produces a sustainable vacuum pressure, allowing HVAC technicians to simulate the pressures draft inducers produce on furnaces while determining when pressure switches open and close, all without a furnace running or the pressure switch even attached to the furnace. You can reduce inventory by stocking just adjustable pressure switches and a few OEMs for warranty furnaces. This means you can always have the right pressure switch, even in the middle of the night.

The Draft Simulator also addresses safety issues, allowing you to catch a furnace problem before it becomes a tragedy. A pressure switch, which has a diaphragm and microswitch inside, senses pressure inside the furnace and lets electric current flow when the pressure is normal. If the pressure reaches a dangerous level, the switch shuts off the electrical current to prevent damage. As an example of what can happen, if a furnace runs while the flue or heat exchanger is partially blocked, carbon monoxide poisoning or a deadly fire can result.

A truly adjustable, or universal, type of pressure switch does exist, but until now, many HVAC companies used them only for emergencies and most hesitated to use them at all. You can install one in the middle of a cold night for the furnace to run, say, until you can come back and replace it with the right switch.