Furnace Start Up Flashcards
Furnace must be wired electrically and ground according to what? In the absence of that you should use?
Canadian electrical code (CEC), or CSA C22.1
The blower motor should be checked for.
Shipping blocks or brackets removed, motor mount checked for tightness
3 ways to check for a gas leak
Test dial on gas meter
Commercial leak detector (soapy water solution)
Electronic leak detector
How to check gas leak with test dial
Turn off gas to all appliances minus the one you’re working on, go to gas meter, locate test dial mark where dial is, wait ten minutes see if it moved.
What do electronic leak detectors detect
Detects the mercaptin.
All venting systems are required to first follow
Appliance manufacturers installation instructions.
All venting must match the what?
The category of furnace it is intended
All metal vent and vent connectors must be
ULC approved and adhere to b149 gas code
Metal vent connector material must be installed so that there is no
Dips or sags with all joints fully inserted and locked together.
All plastic vent must be certified to
ULC S636 and must be clearly marked.
Excessive air leakage could cause what
A shortage of warm air in certain rooms
On new construction it is good practice to?
Inspect entire heating ventilation and air conditioning.
What do you match the heat anticipator to?
The amperage of the 24 volt control circuit.
How to set a single stage Manifold pressure
Must turn off gas at the gas cock first and connect the manometer to the outlet pressure port on the gas valve
Failure to set the air temp rise can result in?
Reduced furance life
Where is the tempature rise readings taken from?
The supply air plenum but not in direct view of heat exchanger
What must you do if temp rise is to low or to high
If to low decrease fan speed if to high increase fan speed.
What are the speeds on a pcm used for
Low is continuous fan op
Medium is for heating mode
High is for cooling
How to change speed in an ECM
Changing a series of small switches “dip sticks”
How to test a high limit
Remove motor lead from heating terminal and placing it on a park terminal ( terminal that is never energized)
In sequence of operation what is considered the pre purge and how long is it
1.Call for heat R&W closes
2.relay coil energized, closes contacts for inducer motor
3.pressure switch closes
Takes 15-45 seconds
In the sequence of operation what steps are considered the trial for ignition.
- Relay coil energies, closes contacts for hsi
2.relay coil energies, closes contact for gas valve
3.burners ignite
4.flame proves through rectification
5.hsi de-energizes
How long after the gas valve energized does it take for the main blower motor to start
30-45 seconds
Where would you find the primary limit switch
Next to the heat exchanger
What type of venting is used for a condensing gas appliance
Bh venting
