Who makes VAV boxes?
The Johnson Controls single duct units along with all VAV family model types of Johnson Controls are manufactured and assembled with a patented multi-point, center-averaging, airflow sensor called the FlowStar sensor.
How much does a VAV box cost?
Installed cost of a VAV box with controls is usually between $2000 and $35001. Installed cost for box zones with 4 to 8 diffusers or smaller is more than for VAV diffusers.
What is fan-powered box?
fan-powered terminal (FPT), fan-powered box In an air-conditioning system, a variable air valve with an auxiliary fan to mix induced air from a ceiling plenum with the primary air.
What are VAV boxes?
A VAV — i.e., Variable Air Volume — HVAC (heating, ventilation, and air conditioning) system that supplies air at varying levels or amounts at a constant temperature. These comprise of multiple VAV terminal units or boxes that diffuse air in specific areas of a large indoor space, such as an auditorium.
How long does a VAV box last?
The accuracy with which these original VAV boxes can control the air flow depends very much on the life of the springs and other mechanisms. Generally speaking VAV units which are in continuous operation would have a useful working life of 15 to 20 years.
What is the difference between parallel and series fan powered box?
In a parallel flow terminal, the fan is outside the primary airstream and runs intermittently, that is, when the primary air is off. In a series flow terminal, the fan is in the primary airstream and runs constantly when the zone is occupied.
What is a parallel fan powered box?
Parallel fan-powered terminals have fans that only switch on during the heating mode to pull warm return air from the ceiling plenum: Since the unit fan is off during the cooling mode, the box acts like a single duct VAV and simply varies airflow from the air handler to maintain room temperature.
What is used to warm the air leaving a VAV box?
In these systems, a fan-powered variable air volume box reduces the volume of the primary 55oF air stream; if the space requires additional heat, the fan in the box is energized. This allows any warm air above the ceiling to be used to heat the space.