HVAC Control and Direct Digital Controls 2 - An HVAC technician who knows nothing about HVAC control systems would wonder how these HVAC control systems work. To understand HVAC controls, one must understand basic electricity and circuits.
DDC Integration | HVAC DDC Controls - This is an electrical project which is in the process of changing the old control system to a new DDC control system. Installing new controls in an occupied building takes plenty of planning to avoid interruption in air conditioning or heating. The old control system was a basic electro-mechanical control system which little more than just basic building management control.
DDC Programming Logic 3 - DDC control logic blocks have practically an unlimited way of arranging the blocks for HVAC control. Below is an example of a line of logic blocks arranged for static pressure control of a VAV air handler supply fan using a variable frequency drive. This same arrangement could also be used for static pressure control using a bypass damper instead of a VFD. (more…)
York VAV Air Handlers | HVAC Zoning - This York air handling unit serves several VAV boxes and runs on a static pressure control set point determined by a DDC program. This program has a static pressure control setpoint and sends a signal to the variable frequency drive to speed up or slow down the blower to maintain the proper static pressure control setpoint. When the VAV boxes need more air the drive speeds the air handler blower up.
When the VAV boxes need little the drive slows the blower down. The VAV boxes are controlled by a thermostat in their respective zones.
York Variable Frequency Drives VFDs | HVAC Control - Variable Frequency Drives or VFDs have added a whole new dimension to energy efficiency and control. These drives, or VFDs, are hooked up to two different York VAV air handlers that have two three-phase motors a piece. (more…)
