by High Performance HVAC | Direct Digital Controls |
How DDC Status Works – DDC and Status – Is the Device On or Off
This is a current switch sometimes referred to as a CT switch.
The basics of DDC include learning about the status of a fan or a compressor or pump. How does a DDC controller read the status of the device it is monitoring? There are several ways to prove a device is running and some pros and cons of each type of device used to monitor on or off status.
This is a basic DDC guide or reference to help a person understand the basics of DDC status and how it works. When one learns how DDC status works they can improve their troubleshooting skills.
Too many maintenance technicians and others including HVAC technicians don’t understand DDC systems or building automation systems and are therefore crippled when it comes to troubleshooting DDC systems.
High Performance HVAC hopes to change that and help HVAC techs and HVAC maintenance staff learn the basics of DDC systems including how DDC status works. Once someone understands the basics about DDC a light will turn on and they will see that DDC is not really rocket science.
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by High Performance HVAC | Boilers |
Boiler Types - There are many different types of boilers in the boiler room today in a variety of heating applications. There are two main categories of boilers among the different boilers and those two categories are steam boilers and hot water boilers. Either of those categories can be fueled by oil, gas, or electric (although electric is uncommon for steam boilers). (more…)
by High Performance HVAC | Refrigeration |
Carrier Chiller w/Air Source Condenser
HVAC Centrifugal Compressors - Centrifugal compressors are used in many applications including pipeline transport of natural gas along with many other related applications including vapor compression refrigeration. These compressors have different operating limitations than the reciprocating compressor, the scroll compressor, and the rotary compressor.
They work in an operating range where it works efficiently however outside of this range, either the over or under that operating range is basically useless. Other issues make them not ideal for use in certain applications because of the operating range issues. (more…)
by High Performance HVAC | Gas Furnaces |
You can see the rust holes up near the sheet metal plates in this heat exchanger
Dangerous Cracked Heat Exchangers in Furnaces - Everyone wants heat when old man winter arrives in the fall. Many times we take it for granted. When the temperature falls all we have to do is go to the thermostat and turn the heat on. Usually, this is not a problem. We turn the thermostat on and the heat comes on. When we first turn the furnace on we have a slight burning odor that comes from the system. (more…)
by High Performance HVAC | Commercial HVAC |
Actuators for Chilled Water Valve - These chilled water actuators control the flow rate for a chilled water system in a data center. There are various sequences of operations for chilled water systems and the sequence of operations is usually always different from one chiller plant to another chiller plant. (more…)
by High Performance HVAC | Direct Digital Controls |
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.
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by High Performance HVAC | Buyers Advice |
Boiler Efficiency Options - High Performance HVAC wants to help you understand your next boiler purchase better. To do this we want to break down all the different types of boilers and components, and various options and features that you may find when making a purchase.
Typically, you want to find a like replacement for the boiler you currently have installed, or if you are buying a new boiler, you want a system that will handle the load and is durable. The most important feature of the new purchase is usually the fuel efficiency simply because the cost of running the new system will give you pay back over time for the new purchase.
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by High Performance HVAC | Buyers Advice |
Air Conditioner Inverter Review - Many mini-split air conditioners and heat pumps use inverters for efficiency. Conventional split system air conditioners and heat pumps can now be purchased with inverters for ultra-efficient heating and cooling.
Inverter air conditioners came to the USA in the form of ductless mini-split air conditioners. They were later expanded to ductless mini-split heat pumps. Inverter air conditioners and inverter heat pumps are considered the most efficient systems available on the market. This is true for conventional systems as well. That includes air source air conditioners and air-source heat pumps. Finally, inverter air conditioners and inverter heat pumps come close to matching the efficiency of geothermal heat pump systems. (more…)
by High Performance HVAC | Refrigeration |
Rotary Compressors - The rotary compressor used in HVAC applications for air conditioning and heating systems offer some of the most efficient air conditioner and heat pump systems one can find on the market.
Despite the rotary compressor being a key component of an air-source air conditioner or heat pump the efficiency offered by this compressor when used as a modulating compressor can exceed efficiency ratings of some geothermal systems.
When the compressor is coupled to an inverter and the proper inverter control system the efficiency of the air-source air conditioner or heat pump system spike to match those of some geothermal air conditioner or heat pump systems.
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by High Performance HVAC | Thermostats |
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.
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