Variable Speed ECM Blower Motors | HVAC Heating & Cooling Systems

Variable Speed ECM Blower Motors

An ECM Variable Speed Blower Motor in a squirrel cage blower

Variable Speed ECM Blower Motors – Variable speed blower motors have become increasingly popular in residential air conditioning and heating systems and for good reason; these motors increase efficiency of the systems and offer a whole range of other benefits that help the system and the consumer.
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Variable Speed ECM Blower Motors

Variable Speed Blower Motors first offer a higher efficiency for air conditioning systems based on the manufacturers set up of the control with the ECM Variable Speed Motor. Each manufacturer calls it a different thing such as Trane calling it the Comfort R and Carrier calling it Infinity Control. Despite what the manufacturer calls it helps efficiency with air conditioning by starting the blower slowly and letting it run at a 50% speed for the first few minutes (up to 7 minutes) to remove more humidity. This increases comfort and efficiency by removing more moisture from the air. The lower the humidity in the cooler you will feel so the variable speed blower with this type of control will enhance comfort.


Closing Off Part of the House To Save Energy on HVAC | HVAC Efficiency

Closing Off Part of the House To Save Energy on HVAC – I have a Heil gas/electric package unit in my home. I, particularly, want to know, if I can close off a section to save on heating. Heating dealers have not been helpful as they hedge on whether and how this can be done with the system still running at it’s most efficient. I have closed doors to seal off area. Then closed floor registers. Should I also close air return in that area? I just read this should not be done at all as it decreases units efficiency? Will you please advise. I am thinking of closing off part of the house to save energy on HVAC. Thank you. (more…)

Variable Air Volume Box with Hot Water Reheat | Commercial HVAC

Variable Air Volume Box with Hot Water Reheat

Variable Air Volume Box with Hot Water Reheat

Variable Air Volume Box with Hot Water Reheat – The variable air volume box or VAV box is a commercial solution to adding multiple zones to large buildings. VAV boxes offer zoning solutions so that separate zoning demands or temperature selections can be maintained in different areas of the building. If the president of the company wants the temperature in their office to be 70 degrees Fahrenheit but the vice president wants their office to be 74 degrees Fahrenheit then it is possible with the VAV zoning system as long as their VAV boxes are on different zones.

Variable Air Volume Box with Hot Water Reheat


This particular VAV box in the picture is not fan powered. It relies on the main VAV air handling unit to provide all the air. Generally, when a fan powered VAV box is calling for heat the damper inside the VAV box closes down so that minimal CFM’s are coming through the primary duct from the air handler. The fan turns on and pulls air from the plenum space above the ceiling. This plenum air is normally warmer than the air inside the occupied space. The heating system kicks in and adds heat to the air until a set point is attained. The heat for a VAV box can typically be a hot water coil or electric heat strips. The VAV box in the picture has hot water reheat and is controlled by a building automation system or DDC. Building automation systems are capable of being linked to the internet for remote control and monitoring which adds many beneficial factors for managers and technicians of commercial property. A single building can have several hundred VAV boxes and with a DDC system managers can quickly see where problem areas are or change control set points with a few clicks.

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Variable Air Volume Box with Hot Water Reheat

Air Conditioning and Heating Sizing | HVAC Technical

Air Conditioning and Heating Sizing - It is not uncommon for HVAC estimators or HVAC contractors to use various rudimentary techniques which are generally referred to as rules of thumb. Some will say on the low end you need 1 ton of cooling for every 500 square feet. On the high end you will need 1 ton of cooling for every 700 square feet. These rules of thumb will also generally take into account a basic heat gain calculation for the kitchen and the number of people who will occupy the structure. (more…)

The NEC and HVAC Chapter Two

The NEC and HVAC Chapter Two – Chapter Two of the National Electrical Code (NEC) covers Wiring and Protection and starts at Branch Circuits, Feeder circuits, GFCI requirements and protection,. An HVAC installer may want to pay attention to branch circuit requirements. Article 220 in Chapter two of the NEC includes calculations for branch and feeder circuits including service calculations. (Table 220.3) (more…)

Rooftop Economizer CO2 | HVAC Control

HVAC Rooftop Economizer - CO2 ControlRooftop 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 which 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 space while venting the air laden with CO2 to the outside. (more…)

Hot Water Unit Heater Protecting a Mechanical Room

Hot Water Unit Heater Protecting a Mechanical RoomHot Water Unit Heater Protecting a Mechanical Room

Unit heaters are used in various places to protect equipment and provide comfort to occupants. This hot water unit heater provides protection for a mechanical room where there is a large air handler and other associated equipment in the mechanical room. This system is controlled by DDC. A thermostat on the wall detects the temperature of the mechanical room. The DDC system will maintain a temperature set point by energizing the hot water unit heater fan and modulating the hot water valve open on the hot water piping. The actuator and hot water valve can be seen in this photo on the right lower half of the system. The valve is a two position valve so it is either open or closed with no modulating the valve on the unit heater. Other unit heaters for heating mechanical rooms or providing comfort include electric units heater when hot water is unavailable, gas fired unit heaters when gas (either propane or natural gas) is available, and infrared heaters typically found in large garages or warehouses for basic comfort of workers in those spaces. There are also steam unit heaters that utilize steam and a steam coil for heating spaces where steam is available. Most unit heaters are forced air unit


Ceiling Fan in a Garage | HVAC Airflow

Ceiling Fan in a GarageCeiling Fan in a Garage | HVAC Airflow

This ceiling fan keeps the air moving in a large garage where repairs are made to heavy machinery. In addition to providing a level of comfort by keeping the air moving in the shop the ceiling fan also helps to keep noxious fumes at higher elevations and moving towards the exhaust fans so the noxious fumes from heavy equipment can be removed from the shop area. The black metal you see hanging from the ceiling of the shop are baffles to keep the noise levels to a minimum. The whole shop is designed to keep noxious diesel fumes from the vehicles being repaired from affecting the occupants of the shop.  (more…)

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