Trane Air Handler AHU with Electric Duct Heater
Trane Air Handler AHU Electric Duct Heater
This Trane air handling unit photo shows a Trane AHU with electric duct heater above the Trane air handler in the supply duct. In places where natural gas is not available and propane LP gas is impractical or not wanted for use electric heat makes a good source for heating. This electric duct heater is is situated in the supply side of the air handler instead of being inside the air handler. In all situations when duct heaters are used the heater will not energize until air flow is proven. An airflow proving switch is usually used to prove there is air flow through the duct before the electric heaters can energize. Air flow proving switches can be used for either electric heaters or gas fired heaters. The air flow proving switch in this case is nothing more than a pressure switch across the ductwork so the pressure switch reads a negative on one side of the duct heater and a positive on the other side of the duct heater. That pressure causes a bellows switch inside the pressure switch to close and allows the duct heater to energize. (more…)
HVAC Reznor Heating System | LP Gas Unit Heater
HVAC Reznor Heating System LP Propane Gas Unit Heater – this Reznor unit heater provides heating for warehouses, garages, and other open spaces which can be heated with unit heaters. Unit heaters are ideal for big open areas which need heating without duct work being used to channel the air into the space. Sometimes these unit heaters are also used in mechanical rooms for protection of the other HVAC equipment and piping to prevent freezing conditions inside the mechanical rooms. The unit heater can be quickly installed and put into service in only a few hours once electrical service and gas service is provided in the location where the unit heater will be located. This unit heater is located in a remote camp site where electricity is available but natural gas was not available. LP or Liquefied Propane is trucked in to fill large LP Propane tanks located near the buildings which use these unit heaters to produce heat. A propane piping system and a series of propane gas regulators were installed and these unit heaters utilize the propane in the tanks being fed by this piping system. The regulators reduce the pressure from the tank to a usable pressure for the unit heater. (more…)
Liquid to Vapor Propane Evaporators | HVAC Heating
Liquid to Vapor Propane Evaporators
These evaporators serve a large complex where natural gas is unavailable. The complex needed a fuel for boilers for heating and domestic hot water so these evaporators were installed to along with two very large LP tanks to handle the heating needs of the complex. As a liquid propane (LP) has a specific weight of .504 (where water is 1) and propane vapor has a specific gravity of 1.5 (where air is 1) making propane vapor 1.5 times heavier than air. It is important to note that propane vapor is heavier than air as propane can build up in low spaces and create a hazardous condition. One gallon of LP will expand 270 times when it becomes a vapor and at atmospheric pressure propane liquid will boil and a become a vapor at -44 degrees Fahrenheit. For each gallon of LP 36.6 cubic feet of fuel can be realized after evaporation making it an ideal fuel for remote locations where other fuels are either not available or too costly. (more…)
Natural Gas or Propane
What is the best for you when choosing between either natural gas or propane for your heating system fuel supply? In some cases you will not have a choice between natural gas or propane since having natural gas supplied to your home or business will require a natural gas pipeline near your home or business. If there is a pipeline near your home and you do not have a meter you can call the company and most of the time they will install the meter next to your home for no cost but it is always good to ask if they are going to charge you for installing a meter for use in your residence or business because every gas company is different. If you do have a meter for your residence or business you also have the choice of using propane instead of using natural gas. The difference is that natural gas is delivered through a pipeline usually underground where propane will require you to have a tank and get propane deliveries from a propane supplier on a schedule. Other differences include cost of propane and this varies from region to region and company to company. Prices also vary according to market conditions and they price for both and can be volatile. Propane does have more BTU’s per cubic foot.
Standing Pilot Gas Valve Propane Heating | HVAC Heating – How It Works
The standing pilot gas furnace uses a standing pilot to light the main burners. Many gas fired water heaters have the standing pilot ignition system. The standing pilot gas ignition system is sometimes referred to as a safety pilot because it increases the safety of ensuring the main burners are lit. The standing pilot can be used on a natural gas ignition system or an LP ignition system. These heating ignition systems are older and are slowly being replaced by the more modern and safer electronic ignition systems.
The standing pilot ignition system uses a thermocouple to detect the flame on the pilot. As long as the tip remains hot and the standing pilot thermocouple is in good working order the system works good and heat is provided when the thermostat calls for heat. The thermocouple is the device which proves the pilot flame.
Outside All Weather Boiler
Outside all weather boilers are used in circumstances where it is not possible to install the boiler inside a mechanical room or anywhere in the building. There some considerations one needs to take into account about having an outdoor boiler especially if it is for a residential application. First is an outdoor boiler is not available in the high efficiency ranges that indoor boilers are available for efficiency ratings. Another consideration is the outside boiler and piping needs to protected from freezing conditions. The boiler in the photo is a propane gas fired boiler but many of the boilers available for residential application are wood boilers. No matter the fuel the boiler consumes the outdoor boiler and hot water piping need to be protected from freezing. Many of the outdoor boilers have controls to prevent boiler freezing and pipe freezing however the boiler should be checked for these types of controls before putting the boiler into service. If you are considering an outdoor boiler or considering purchasing a house with a residential boiler these factors and considerations should weigh in on your decision.
Gas Furnace Facts – Gas Furnaces are the most used types of heating appliance for our homes and businesses and modern gas furnaces range in efficiency ratings from 79% to 98%. Gas furnaces can either use propane or natural gas for fuel and this largely depends on whether natural gas is available at the location where the appliance is located. Propane is used in rural areas and in urban areas where the natural gas pipeline infrastructure has not been installed. Natural gas is delivered via pipeline while propane is delivered via trucks and pumped into tanks located on the premises where the gas furnace, water heater or other appliance is located that utilizes propane for fuel. The other differences between propane and natural gas are propane is heavier than air while natural gas is lighter than air and the BTU rating between propane and natural gas, the size of piping used to deliver the two different gases to the appliances, and the pressures of the gases at the the point delivery to the appliances. Natural gas produces 1,000 Btu’s of heat per cubic foot burned and Propane produces about 2,500 Btu’s of heat per cubic foot. (more…)
Gas Furnace Components
There are different types of gas furnaces which are available for purchase today and the older models which were installed many years ago still in operation. The older models were typically atmospheric type gas furnaces and used a lot of gas to produce heat much of which went up the flue because efficiencies were low. The standing pilot atmospheric type gas furnaces still exist today but they are slowly going the way of the dinosaur as they are being replaced by newer more efficient furnaces. We will take the typical modern gas furnace and break it down into different components and parts and then put it all back together again so that you will understand each part and how a gas furnace works. Each manufacturer has their own way of engineering their products but the principles and gas furnace components are basically the same. We’ll describe each gas furnace component necessary for the proper functioning of the gas furnace. Gas appliances require piping and gas piping in some states or provinces may be regulated by the plumber’s board but many HVAC contractors are qualified for running gas pipe. Many HVACCompanies have a plumbing department or the Plumbing Company has an HVAC department. Either way the gas piping should be done by a professional who is familiar with gas piping, gas pipe sizing, and the Fuel-Gas Code (other local codes may apply, consult with your local code authority before beginning a new piping job). Safety is the primary factor with any heating and we will stress this as we go along covering all gas furnace components. Of course we don’t know everything but we do know a lot about HVAC so if we leave something out I’m sure the High Performance HVAC readers will let us know as they always do. Suggestions and comments are welcome about gas furnace components and anything else you want to contribute concerning HVAC.
Changing a Standing Pilot Boiler to Electronic Ignition
The Honeywell Y8610U Intermittent Pilot Retrofit Kit
How many times have you spent time in the cold trying to light a pilot light on a standing pilot gas system? I am certain if you are a service technician then the previous sentence can be qualified with “How many frustrating times”. You go on a service call and find the old standing pilot gas system, whether it is a water heater, furnace, or boiler, and you find the thermocouple is bad or some other reason that is keeping the pilot light from staying lit. You clean the pilot burner and replace the thermocouple and walla…………..it lights and stays lit. The magical standing pilot works again. There is another option for you and your customer and while it is not recommended in every situation it can help eliminate those pesky repeat service calls where the pilot continues to go out for whatever reason………………….the ghostly sudden draft is one of the big reasons. Honeywell produces an electronic ignition retrofit kit that is ideal for residential and light commercial gas furnace systems that need to be upgraded from standing pilot to electronic ignition (covers BTU ratings up to 270,000).
Honeywell Y8610U6006 Gas Valve Intermittent Pilot Retrofit Kit Available here
Natrual Gas Regulators
Natural Gas Properties and Furnace Heating Efficiency
Natural Gas is a popular fuel used for heating systems in America and other countries. If we look at the properties of natural gas and the heating efficiency of natural gas furnaces we will see that natural gas furnaces lose efficiency because of what is contained in natural gas as it is delivered to your home for consumption by your natural gas furnace. Natural gas in its raw form coming straight from the ground needs to be refined to remove impurities that should not be contained in natural gas. As you read below you will see that in the refining process moisture is removed from the natural gas however during the refining process some of the moisture in the natural gas remains and therefore this affects the efficiency of your natural gas furnace. Condensing furnaces always have a drain on them to drain away one of the byproducts of combustion which is water/moisture contained in the gas. This is why it it is called a condensing furnace simply because it condenses all the moisture from the gas during the combustion process. I am certain there are people who have had a problem with a leaking furnace in the winter time where the drain became clogged or plugged and required someone to clear the condensation drain to clear the drain. This is the water that is condensed from the natural gas during the combustion process along with moisture contained in combustion air. Any moisture in the gas will affect the efficiency of the furnace. The less impurities in the natural the more efficiency you will get from the gas furnace.