I have honeywell vt117 TRV fitted with number settings 1 to 6 with an economy button set at number 3. If my thermostat downstairs is set to 21C for example; what temperature will the numbers on the TRV represent?
If memory serves me right the red button is at 18C and the settings are 2 degrees apart.
Heating with Electricity: Electric Furnaces, Heat Pumps
By: Yale Wolk, Erinson Home Inspections
Electric Furnaces
In many homes the heating system is electrically powered. One such system is the electric furnace, which functions like a gas or oil furnace but does not use combustion to produce heat. Rather it uses electrical resistance heating coils to provide warmth to the air that blows throughout the house. Because there is no combustion, there are no concerns about carbon monoxide or water vapor in exhaust gasses. There is no exhaust since nothing is burning. The electric furnace is a dependable and long-lived heating system and should perform satisfactorily for many years. However, it is an expensive system to operate. The cost for electrical power far exceeds the cost of gas or oil in most of the country, and for this reason, electric furnaces are rarely installed in new construction.
Heat Pumps
In electrically powered systems, the successor to the electric furnace has been the heat pump. Like an electric furnace, a heat pump does not use combustion to produce warm air. It does not burn any fossil fuel. Rather, it uses principles of thermodynamics to absorb heat from one source (typically, the outside air), transport it inside the house and then release it into the house air. To do this, it uses refrigerant, usually R-22 and often referred to as Freon- DuPont’s brand name. R-22 has the unusual property of being capable of absorbing warm air from a source, transportign it and then releasing it elsewhere. As noted, the typical heat pump draws warmth from the air outside the home, and is referred to as an air source heat pump for this reason. In the heating mode, the heat pump will draw warmth from outside air, transport it via copper tubes and then release it inside the house.
Air Handler Unit. A heat pump consists of two units. First is the inside unit, often called an air handler. There are two compartments. Inside one is a large fan (the blower). Inside the other is a device that looks something like an automobile’s radiator. It consists of a series of coils weaving through a finned metal structure. This is the air exchanger, where R-22 circulates through coils, meets the inside house air, and the warmth collected outside is released into the inside air. The warmed air is then blown throughout the house by the fan, and is channeled through a system called ductwork.
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