What Temperature Should I Set My Programmable Thermostat To – 4) Please confirm this advice if you would; it is better to have your thermostat left at 70°F. to 72°F. during the day while your home is empty and adjust accordingly when you get home as opposed to shutting off the heater/ac and turning on when you get home. I would think this would put less strain on the unit. Thanks in advance for your help. (more…)
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 system that will handle the load and is durable. The most important feature about 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.
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.
Hot Water Boiler Reset Control
We are looking at replacing our boiler with a new boiler. The HVAC contractor, I suppose he is the salesman for the HVAC contractor, is trying sell us what he refers to as a reset control for our boiler. He tells us it will save us more money by making our boiler more efficient. I think I understand how it works but my wife is not entirely sure about it. Can you tell us what you think about a boiler reset control and how it works?
Thanks and we have learned so much from High Performance HVAC. Keep up the good work.
Rooftop 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…)
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 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…)
HVAC Temperature Measurement Conversion – In air conditioning and heating applications it is necessary to accurately measure temperature to offer control of the temperatures relative to the application for which the HVACR equipment is serving. There are four separate temperature scales used to measure temperature and it becomes necessary at times to have the ability to convert between the different scales. The two most common scales used by most people are Fahrenheit and Celsius. Fahrenheit is mostly used in the United States where the culture has resisted changing from standard measurements to the metric system. Celsius is used throughout the world including the United States and Canada. Scientist often use Kelvin and Rankine measuring scales to measure temperature. These temperature scales, Rankine and Kelvin, are uncommonly used in popular culture no matter where you live in the world except by the scientific community and are often used to measure extreme temperatures. (more…)
Heat Trace Tape Control for HVAC Piping
HVAC Piping systems especially in the Northern regions need a way to freeze protect piping the runs outdoor which is a necessity in many different HVAC application. To protect HVAC piping from freezing heat trace tape is wound around the pipe and controlled by an outdoor thermostat or temperature control that energizes the heat trace tape and keeps the pipe from freezing. Heat trace tape looks similar to Romex and simply provides electrical resistive heating for the pipe. Heat trace tape is made of many layers that begins with the heat trace wire. The wire inside the insulation (typically 16 AWG) that heats up is surrounded by a conductive core. The conductive core is surrounded by a thermoplastic insulation. This has an outer copper overshield that is also in a thermoplastic insulation as an outer jacket to protect the inner layers of the heat trace tape. The photo shows a heat trace tape temperature controller that energizes the heat trace tape to protect the piping from freezing. In this particular case, the temperature controller controls the heat trace tape on a chilled water piping system and a hot water piping system. Tanks can also be wrapped with heat trace tape and then insulated for further protection. (more…)
Domestic Hot Water Mixing Valve and Domestic Storage Tank
Domestic Hot Water Mixing Valve and Domestic Storage Tank – This domestic hot water mixing valve offers a way to temper the hot water coming from a hot water loop and boiler. It is very important to maintain the appropriate and desirable temperatures of water used for domestic water use. First you want to maintain a safe temperature so people are scolded by extremely hot water temperatures. Boiler loops generally work on a temperature of 180 degrees Fahrenheit and this temperature is too hot for human contact without scolding or seriously burning the skin. A mixing valve is used in the loop to maintain a safe temperature for human comfort. The hot water is mixed with cold water at the mixing valve and the result is the temperature dialed into the mixing control valve which has a range of 120 degrees to 140 degrees if used for domestic hot water applications. Other mixing valves can be purchased that will give a whole range of temperatures including mixing valves that can be controlled by PLCs or DDC to maintain specific temperature ranges for whatever the desired temperature is for the application. (more…)
Hot Water Boiler Components and Controls | Combustion Control
This photo shows the boiler cabinet open exposing controls and basic components of the boiler. The module on the left is the ignition control module which controls the sequence of operation for ignition and burner controls of the boiler. When the boiler is enabled to run usually by a thermostat or controls the ignition control module begins the process of firing the burners. The process typically begins by having the ignition module check the safety circuit to ensure all safeties are normal and not in alarm. This includes energizing the inducer or forced draft fan motor and any limit switches and a flow switch to ensure the boiler has water flow.
Hot Water Boiler Components and Controls | Combustion Control
The inducer or forced draft fan motor causes some pressure switches to close proving that combustion air is available and that the combustion gases will be exhausted when the burners fire. After the safety circuit has been proven to be okay the ignition control opens the gas valve while simultaneously activating the spark ignition to ignite the gas now being supplied to the burner(s). Once the burners ignite the fire is proven, usually by a state of the art flame sensor, the ignition control module deenergizes the spark ignition. As the water heats up it is sense by an aquastat or temperature sensor. When the temperature of the water reaches the set point of main boiler controller the ignition control closes the gas valve and the main burners shut down. The inducer or forced draft fan motor continues to run for period of time so that all the combustion gases in the system are purged up the boiler flue or boiler stack.