Furnace Startup, Testing And Troubleshooting Flashcards
(42 cards)
4 things that must be checked prior to furnace startup?
-electrical connections (junction box, circuit board)
-leak test from gas cock to appliance
-visual inspection of venting and duct connections
-manufacturers startup procedures
When inspecting the blower motor prior to startup what things are you looking for that need to be removed?
Shipping blocks, or brackets. Inspect center housing
Three ways to check for a gas leak are?
-Test dial on gas meter
-commercial leak detector (soapy water)
-electronic leak detector
When checking the test dial on the gas meter what must be done to ensure a proper test is completed?
-Make sure no appliances or pilot lights are running
-mark or take note where the smallest test dial is located.
-wait 10 minutes before checking for movement
Can you use mix different brands of venting together when installing system 636 venting?
No
Why is it important to inspect duct connections?
Poor duct connections can have a negative effect on performance due to air leakage
True or false. A filter can be installed inside or outside of a furnace?
False. It must be installed outside the appliance so that it is accessible to customer without opening the furnace
In order for the furnace to produce the right amount of heat and run at peak efficiency what must be done in regards to gas pressure?
-Must have proper gas supply pressure
-correctly set manifold pressure
What must be done to furnace installed at high altitude?
Derated
True or false. All furnaces installed at high altitude must be derated?
False. Check manufacturer specifications. Some furnaces are already capable of running at high altitude
True or false. On a two stage furnace you must set the manifold pressure for each stage separately.
True
Why is it important to check temperature rise?
To ensure heat exchangers do not overheat due to insufficient heat transfer.
When checking temp rise on the supply side. Where must the thermometer be in relation to the heat exchanger?
Out of view of the heat exchanger. Radiant heat can skew results
What is the formula for temp rise?
Supply-return=temp rise
If the temperature rise is not falling within manufacturers specs and your gas pressure is set correctly what else can be done?
Adjust the blower speed
How do you test the high limit switch in a furnace?
Disconnect blower and run furnace
How many types of voltage will a typical circuit board have?
Two
What direction must furnace venting slope.
Upwards away from furnace
Max distance on supports for 636 venting?
5’
What should the heat anticipator setting match?
Amp draw of the 24 volt circuit
Calorific value of nat gas and propane?
Nat gas 1000/cubic foot
Propane 2500/cubic foot
What is the purpose of a combustion analysis?
To ensure proper combustion is taking place and that the gas fired appliance is operating efficiently
What are manometers used for?
Measuring gas pressure, pressure drops across filters and coils, pressures created by induced draft motor as well as pressures in the ductwork
What are tachometers used for?
Measuring the speed of motors and fans
