3. Residential Heating Systems and Equipment

A furnace is a piece of equipment that is used to change _____ into heat energy.

Fuel

Which of the following is not required in a solid fuelled furnace?

Gas Valve

What are five types of furnaces configurations?

Upflow, Counterflow, Horizontal, Lowboy and Multi-positional

What are the different furnace configurations styles based on?

The arrangement of the blower and the heat exchanger components.

What is the most common style of furnace?

Highboy or Upflow furnace

Which of the following is an advantage of the radial system?

It is simple to install

perimeter loops systems are found mostly in what kind of heating instillations?

Uderslab

What is the most common type of distribution system used today?

Extended plenum

What is the heating value of natural gas?

1000 BTU/ft3

What is the heating value of propane?

2500 BTU/ft3

What is the heating value of butane?

3400 BTU/ft3

what is the burner of choice for high rates of combustion in an oil furnace?

atomizing burner

What is the minimum efficiency of a gas furnace allowed to be manufactured and sold in Canada?

78%

The inducer fan on a mid-efficiency furnace is a power vent that allows you to vent out the sidewall. True or False?

False

What are high efficiecy furnaces also known as?

Condensing furnaces

Name three types of gas fire places?

Free standing, zero clearance and insert.

in addition to wall mounted thermostats and switches, fireplaces can be controlled by a?

Wireless Remote

Gas logs make the fireplace look more like a wood fire the logs can be made of?

Concrete or ceramic fibre

Range hoods need to be interlocked over what CFM?

80,000 CFM

Anything over what BTU’s need combustion

50, 000 BTU

The heart of every HVAC system is the?

recirculation equipment

If the heat is supplied by a liquid medium from another source it’s called a?

Fan coil unit.

furnaces are classified by?

fuel type, efficiency or component configuration

what are the two compartments of the furnace?

the combustion compartment or the blower compartment.

what four sets of components in the combustion cabinet?

Fuel supply components, air supply components, heat exchanger and safety controls.

Natural gas and propane furnaces are similar in construction and use similar?

gas valves and burner assemblies

What Solid fuels are not as popular but still used in Alberta?

Coal and wood

what is similar to natural gas in it’s application?

Liquid petroleum also known as propane

What is the imperial system unit for heat?

British Thermal Unit (BTU)

One BTU is defined as the amount of heat required to raise one pound of water 1 degree F and how many cubic feet of air?

55 Cubic feet 1 degree F

What is the Metric unit of heat measured in?

Joules

one BTU is equal to how many Jules?

1055 J

What is a gas valve?

a on-off device that regulates the flow and pressure of the fuel, connected to the manifold.

Name two types of burners in a furnace?

Inshot and upshot

Natural gas is sold by the?

gigajoule

What is the maximum capacity that a propane bottle should be filled?

80%

Propane is often sold by the?

Litre

Most gas furnaces can be converted to propane with a conversion kit. True or False?

True

propane must vaporize in order to be used safely as fuel. true of false?

True

Fuel oil is similer to deisel fuels burned in cars. True or False?

True

What are two ways Fuel oil can be burned?

vaporizing or a atomizing burner

what is one of the main component differences between fuel oil burning furnaces and gas furnaces?

The flame sensing components

How does vaporizing fuel oil work?

Heat is applied to a puddle of oil which vaporizes the fuel, these vapours are then burned after mixing with the air.

How does the atomizing type burner also called an oil burner gun work?

it uses a motor to run an air fan and fuelled pump, the fan forces air down a tube to a combustion chamber to mix with the fuel before combustion. the pump pressurizes the fuel before pushing it through the nozzle. the nozzle atomizes the fuel or breaks it up into tiny droplets, which can be vaporizes more easily.

Older furnaces rely on natural draft to supply air for the furnaces, the air is mixed with the gas before combustion inside the burners. how is the air regulated?

With the air shutters on the burners, and the remaining air is supplied to the combustion process at the point of combustion.

because of the low efficiency combustion process more air must be mixed with the products of combustion to cool them before they exit through the flue to the outside. The mixing of air is called? and is accomplished with what component?

Dilution air is accomplished with a draft hood (called the stack effect or motive power)

What does the heat exchanger do?

Separates the air that circulates through the house from the products of combustion.

how are heat exchangers fabricated?

from stamped steel

what is the old way of fabricating heat exchangers?

welded together and to the mounting flanges.

What are two types of safety controls?

one monitors the flame and shuts off the flow of fuel in the case of flame or ignition failure.

The other type monitors the temperature and shuts off the flow of fuel if the heat rises to high.

What does a thermocouple do in a older furnace?

it’s a saftey control that uses heat form the pilot light to generate a electrical current that hold the main gas valve open.

What will shut off the gas valvein the case of high temperature?

A high limit control alone or in combination (older) with the fan control or a Flame rolloutswitch (newer)

What is the modern safety control used in furnaces to detect a flame ensuring safe combustion by cutting gas flow if no flame is detected?

electronic flame sensor

What is used in oil furnaces as a saftey control for flame sensing?

Cadmium sulfide cell (CAD) which senses light and ensures that there is no fuel pumping into the heat exchanger without ignition.

Thermostats and high limit controls are the same on an oil fired furnace as on a gas furnace. True or False?

True

Solid fuel fired furnaces have a high limit control that functions in which way?

It shuts off the flow of air in case of the temperature getting to high.

is flame sensing used in solid furnaces?

No because there is no automatic ignition or fuel feed.

How does wood pallet stoves with a fuel feed saftey work?

Temperature control senses wether it is to hot (Blower failure) or to low temperature (Flame failure)

Name two types of blowers?

belt driven and direct drive

What powers a direct drive blower?

A capacitor

How is the blower fan controlled in older systems?

Either a dedicated fan control or a combination fan-limit control.

How is the blower fan controlled in newer systems?

Electronic control board

Furnaces are rated according to the amount of fuel they burn or the input rate. The input rate is measured by Btu per hour. What is the relationship between watts and Btuh?

1 watt = 3.413 Btuh

1kW = 3413 Btuh

in what range percent of efficiency do older gas furnaces with a draft hood and standing pilot light have?

55% to 75%

In what range percent of efficiency does a mid-efficiency furnace use?

78% to 85%

what percentage of efficiency does a furnace that has a secondary heat exchanger use?

as high as 96%

What is used on fuel oil and solid fuel furnaces as a draft regulator?

Barometric damper

what replaced draft hood in the mid-efficiency furnaces?

Inducer motor

Name two types of fan coil units?

Electric or Liquid medium

Most air quality experts suggest optimal home humidity level should be between?

33% and 55%

Name four types of humidifiers?

Pan/ Evaperative

Bypass drum style

bypass flow through

Atmoizing

Condenser unit is a package unit that contains?

The compressor pump for the cooling system and the coil and a fan to draw air through the condensing unit.

What does HRV stand for?

Heat Recovery Ventilation system

Cubic feet per minute refers to?

Volume of air

Feet per minute

Refers to the velocity

The perimeter radial system is not commonly use above ground but is often used in?

Under-slab type systems and sometime in special high velocity systems.

how long should the extended plenum run past the last run?

12” beyond last run

what is the best length to reduce the extended plenum and what is the max?

15’-20’ and a maximum of 24’

The amount of fresh air required for combustion systems is determined by who?

by the manufacturer or set by the codes of practice such as the Canadian gas code.

What are some by-products present from the products of combustion?

Carbon monoxide (CO) Oxides of nitrogen (NOx) and unburned carbon or soot.

What is the best for venting solid or liquid fuelled furnaces due to their high heat resistance?

Masonry chimneys or Factory built type A vent

Another name for built in fireplace?

Zero clearance

A - vent and L-vent can be used for what type of appliances? Why

oil-burning appliances because they dont burn as high and the danger of chimney fore is nearly non existent.

If there is flame failure in a older style furnace what is going to stop fuel flow?

Thermocouple

What does the Cadmium Sulfide Cell (CAD) sense?

It senses light and is used as a safety device.

What does CW and CCW mean

clockwise and counter clockwise

which type of filter requires external power?

Electronic air cleaner

What types of pads are used in the pan evaporator style humidifiers?

Wicking Pad

Where does the fresh air pick it’s heat up When traveling inside an HRV and where does the heat come from?

The heat comes from the stale air which is absorbed by the heat exchanger then picked up by the fresh air.

What should never be hooked up to a HRV?

Range hood or dryer

Bh Venting is used for high efficiency furnace venting. Why must this type of venting be used?

Because it can withstand the corrosive properties of any moisture that condenses out of the flue gasses after hey leave the furnace.