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. Continue reading
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. Continue reading
Liquid to Vapor Propane Evaporators
The propane 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 propane evaporators were installed to along with two very large propane tanks to handle the heating needs of the complex. As a liquid propane 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 liquid propane 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 liquid propane 36.6 cubic feet of propane can be realized after evaporation making it an ideal fuel for remote locations where other fuels are either not available or too costly. Propane evaporators are not commonly used except in large commercial and industrial areas where a lot of propane is needed to serve a large amount of heating systems and applications. Expanding liquid propane through evaporators offers an ideal large capacity propane source for heating systems. Many residential systems strictly used vapor propane for their heating needs and do not need propane evaporators or a propane evaporator. Propane heating systems are extremely popular in rural and remote areas where natural gas is unavailable and oil is not desired to be used for a heat source. Propane evaporators offer a controlled way of changing liquid propane to vapor propane for large capacity systems. Continue reading
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 natural gas pipeline near your home and you do not have a gas meter you can call the gas 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 the gas is 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 natural gas 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 versus natural gas and this varies from region to region and company to company. Prices also vary according to market conditions and they price for both natural gas and propane can be volatile. Propane does have more BTU’s per cubic foot than natural gas.
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.