How a Programmable Thermostats Works | HVAC Control

How a Programmable Thermostats Works - Programmable thermostats can save you more than ten percent on your homes utility bills. For that reason a programmable can pay for itself within a few years depending on the type and expense of the type you purchase. I always lean towards Honeywell thermostats simply because I’ve seen their reliability in the field and sometimes ease of use. Among others, you can expect good quality from Honeywell thermostat products. The new, hi-tech style currently out on the market is the Honeywell touch-screen thermostat.
(more…)

Outside Air Dampers with Energy Recovery | Energy Efficiency

Outside Air Dampers with Energy RecoveryThe dampers straight across are outside air dampers or make-up air coming from an energy recovery unit. According to the mechanical code, commercial buildings require a certain amount of fresh air from the outside to maintain good IAQ for the occupants.

An energy recovery unit allows it to be conditioned before being introduced into the building. Other methods include using enthalpy calculations to open economizer dampers and/or CO2 control of the dampers. (more…)

Rooftop Economizer CO2 | HVAC Control

Rooftop Economizer CO2Rooftop Economizer CO2 | HVAC Control – This damper is part of a free cooling system for a rooftop economizer. It is part of an economizer damper system that allows free outside air cooling when the outside air temperature and humidity are ideal. This economizer also works on CO2 control so that if the CO2 levels inside the space rise above a set point the economizer damper opens allowing fresh outside air into the building while venting the air laden with CO2 to the outside. (more…)

VAV Air Handler | HVAC Zoning

VAV Air Handler and HVAC ZoningVAV Air Handlers are ideal for providing zones in a commercial building. Office space typically has several offices and open areas that need to be conditioned for the comfort of the people working in those areas or offices. By installing VAV boxes and zoning the ductwork from those VAV boxes these areas and offices can be kept comfortable using a VAV air handler system. More on how VAV boxes work. (more…)

VAV Box Types Fan Powered and Shut Off

VAV Box Types Fan Powered and Shut Off VAV Boxes - When attempting to name the different types of VAV boxes we find there are different names given to VAV boxes by different people and we find that no one is on the same page when VAV boxes are definitively defined.

We have fan-powered VAV and non-fan-powered VAV’s and we have series and parallel VAV’s and we have VAV boxes with a hot deck and a cold deck that mixes and one of the last projects I worked on some of the VAV’s were referred to as shut-off vavs. Variable Air Volume Boxes (VAV Boxes) regulates airflow into zones using a primary air source from a VAV air handler.

VAV Box Types Fan Powered and Shut Off

  • Cool only single ducted series
  • Fan-powered single duct series with reheat
  • Fan-powered single ducted parallel with reheat - uses plenum air before using reheat for energy efficiency

Aside from the control aspect of VAV boxes, pneumatic, electric, electronic, or DDC, there are many different variations to VAV Boxes and we will attempt to define each type of VAV including offering a diagram of each type and matching it with a specific application. VAV boxes are simply an assembly of a damper, damper controls, and sometimes reheat such as electric heat strips or a hot water coil. VAV boxes get their primary air source from a central VAV air handler and then distribute air throughout a specific zone the VAV box controls.

(more…)

DDC Outside Air Economizer System | HVAC Control

DDC Outside Air Economizer System | HVAC Control economizer dampersDDC Outside Air Economizer System  - Outside louvers allow the DDC control system to open dampers and introduce fresh air into the building. Building automation system, or the energy management system as it is sometimes called, monitors outside air temperature and humidity and based on a calculation and opens the outside air dampers when this calculation determines a precise set point. (more…)

HVAC Damper Actuator for Economizer Free Cooling

HVAC Damper Actuator for Economizer Free CoolingHVAC Damper Actuator for Economizer Free Cooling - This damper actuator controls a free cooling damper for an economizer. It is part of an economizer damper system which allows free outside air cooling when the outside air temperature and humidity are ideal. In the Fall and the Spring when the outside air temperatures are mild it is unnecessary to run the air conditioning system to cool the building if the system is set up for free cooling. (more…)

Outside Air Temperature-Humidity Sensor | HVAC Control

Outside Air Temperature-Humidity Sensor Outside Air Temperature-Humidity Sensor  - The outside air temperature sensor uses a thermistor to read the outside temperature. This sensor also senses humidity using a humidity transducer. The temperature and humidity readings are collected by a direct digital control system and used in a program. Aside from using this information for user interfaces, the information is also used in a control program to open and close an outside air damper.  (more…)

Aquastat Temperature Control | Boiler Components

Boiler Aquastat Temperature Control

Aquastat is the gray box on the left while the circulator is the black pump on the right.

Aquastat Temperature Control - The boiler aquastat controls the temperature of the water inside the boiler jacket. The boiler aquastat is a device to a boiler like a thermostat is to an air conditioner, heat pump, or gas/oil furnace. A boiler aquastat controls the temperature inside the boiler just as the thermostat controls the temperature for an air conditioner or heat pump.

The boiler aquastat will turn the burners on and off and also controls the circulator pump on a hot water boiler system.
(more…)