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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by High Performance HVAC | Refrigeration |

Refrigerant Alarm Control for Chiller Room
This refrigerant alarm serves two chiller rooms and alerts operators and other staff that refrigerant has been released into the mechanical room. Chillers have a built-in pressure relief valve that will release the refrigerant in the event too much pressure builds up in the system. This prevents a possible explosion from too much pressure and also protects the equipment from a catastrophic failure that would make the chiller unusable. (more…)
by High Performance HVAC | Refrigeration |
R-410A versus R-22 Refrigerants - R-22 is a refrigerant that has been widely used in air conditioners and heat pumps for many years. It has been deemed hazardous to the environment and it will begin phase-out by law in the year 2010. The replacement refrigerant for R-22, R-410A, is being produced to meet the rising demand for new air conditioner and heat pump systems. (more…)
by High Performance HVAC | Technical Reference |
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…)
by High Performance HVAC | Direct Digital Controls |
DDC Automated Logic M-Stack - This Automated Logic M-Stack provides a control for multiple pieces of HVAC equipment and integrates network communication all in one single stack. This direct digital control system is integrated with pneumatic controls. DDC allows automated HVAC control processes to take place and adds higher efficiency to an HVAC system. (more…)
by High Performance HVAC | Air Handlers |

Air Handler Water Coil Freeze Stat - The HVAC Air Handler Freeze Stat is a low-temperature limit control and it is used mainly in commercial systems in the ductwork on economizers or in air handlers just before any coil especially water coils. It is a safety and protection control to prevent extremely cold air from reaching the hot water or chilled water coils inside the air handler where the air enters from the economizer.
Under ideal control setup if the freeze stat trips the economizer dampers close and the blower fan stops. This prevents coils from freezing. A frozen coil can bust open and will need to be replaced if it freezes. This is the purpose of the freeze stat in HVAC air handler applications which utilize economizers for free cooling and other purposes.
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by High Performance HVAC | Air Handlers |
Find Tonnage on AHU | HVAC Equipment Nomenclature - How do I find out the tonnage on an AHU (Air Handling Unit)? The label/tag has faded all I have on file is the model number and the serial number, make.
Question Posted By Francisco the Building Engineer on May 3, 2011
Refer to the manufacturer’s website for their HVAC nomenclature of the model number and serial numbers and how those numbers correspond to the tonnage and other technical data. Or you can call your local dealer for the manufacturer and they will tell you. (more…)
by High Performance HVAC | Goodman HVAC Reviews, Heat Pumps |
This Goodman 13 SEER Heat Pump condensing unit is a new installation. The inside Goodman air handler attached to the heat pump condenser via line set was also replaced. It was replaced with this new Goodman heat pump. It’s not a good idea to put a new high SEER air conditioner or heat pump condenser without matching it. It should be matched with a properly rated and efficient air handler especially the coil. (more…)
by High Performance HVAC | Technical Reference |

Some things are very obvious
Home Inspector HVAC Training - Thank you!! I am training to become a home inspector, and the info contained on this site helps identify issues that require an HVAC professional to resolve. (more…)
by High Performance HVAC | Refrigeration |
Refrigeration for HVAC - Air conditioners and heat pumps use the process of refrigeration to provide heating and cooling. What is the definition of the process of refrigeration? Refrigeration is the process of moving heat and depending on whether it is a heat pump or air conditioner and what mode it is in will depend on where you are moving the heat. An air conditioner and a heat pump (in the cooling mode) will move heat outside. The evaporator coil absorbs the heat and the condenser rejects the heat. (more…)