by High Performance HVAC | Thermostats |
Thermostat Wire - Thermostat wire comes in a bundle with the outer jacket being either brown or white. The bundle can have anywhere from 2 conductors inside the bundle or outer jacket and all the way up 8 or 10 conductors inside the outer brown or white jacket. The bundle for typical wire is 18 gauge solid copper conductors and each has its own outer jacket that is a different color than any of the other conductors in the bundle. These multi-color wires are colored differently for identification from one end of the bundle to the other end of the bundle. It can be purchased in a bundle as follows:
This article refers to conventional thermostat wire which is different than the wire you would have if you have a communicating thermostat.
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by High Performance HVAC | Commercial HVAC |
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. (more…)
by High Performance HVAC | Air Handlers |
Air Handler Components 3 - Hot water coils inside of air handler units combine a boiler system or a special capacity hot water heater and forced air to provide forced-air heating. The concept is simple and used a lot in commercial and some in residential.
Commercial systems almost exclusively use a boiler to provide hot water to the hot water coil inside the air handler unit while the residential systems use mainly special capacity hot water heaters to provide hot water to the hot water coil inside the air handler unit.
On a call for heat, a pump is energized to begin the circulation of hot water from the heating source to the coil. The air handler unit blower motor energizes and the air begins to move across the coil. Heat is exchanged from the hot water coil to the air and the air is delivered to its appropriate destination through the ductwork.
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by High Performance HVAC | Gas Furnaces |
Gas Furnace with Drain Pipes to Drain the Condensation.
Furnace Water Leak Condensate Problem - Richard, My furnace is leaking water. It is summertime, so I am not using it for heat except for the blower fan which is hooked up to the air conditioner and the heat. I know the pipes from the outside units run into a box on top of the furnace. I think that is a part of the air conditioner. What can I do to fix the problem if you know what the problem is by my explanation here? Dan
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by High Performance HVAC | Commercial HVAC |
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.
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by High Performance HVAC | Commercial HVAC |
Variable Air Volume Systems - Variable Air Volume (VAV) systems are the best way to zone especially in large buildings. A VAV system with the proper controls and setup will help the building owner realize large savings in energy usage. There are many VAV systems out there set up in different ways. The most common set-up (for DDC) is, of course, usually the cheapest to install.
They have an air handler (DX or Chilled Water) which supplies the VAV Boxes with fixed pressure and temperature of the conditioned air. The VAV Boxes have electric reheat which will heat the air if that particular zone calls for heat (it is not uncommon to also find VAV boxes that have hot water reheat although this usually costs more to install but can save in energy costs). More on how VAV boxes work.
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by High Performance HVAC | Air Handlers |
Air Handler Components. This article will take different types of air handlers and disassemble them part by part. This will give you a good description of each part and hopefully a better understanding of the air handler. Most of the components associated with the air handler are in the air handler. However, there are a few components which are not in the air handler but associated with the air handler.
There are some hot water and cold water coils which are not fixed in the air handler. They are downstream in the ductwork. There are also some gas and electric duct heaters which are mounted in the ductwork. They are completely reliant on the air handler for air flow. These systems will also be covered. Hopefully, this article will offer you a comprehensive look at the air handler, all its parts, and how it functions. (more…)
by High Performance HVAC | Duct Work |
HVAC Duct Systems - Ductwork systems channel the air to the spaces where it is needed from the air handler. HVAC duct systems also will pull the air from the space and channels it back to the air handler where it needs to be conditioned. In some commercial applications, the area above the ceiling is considered the return duct. All the return air is channeled back to the air handler through the plenum where it is conditioned in the air handler. Part of the conditioning process is the air being passed through an air filter and then an exchanger like a coil or heat exchanger. (more…)
by High Performance HVAC | Air Handlers |
York Air Handling Unit Chilled Water Coil - This coil is a cooling coil in a large commercial York air handling unit. The air handler serves approximately 80 VAV boxes and is responsible for providing cool conditioned air to all the zones the VAV boxes serve based on a set point determined in a DDC program and the chilled water coil seen here. (more…)
