Exhaust blower testing for speed with control panel and cleaning. ( Whitfield Example )

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Minister of Fire
Feb 1, 2010
Salem NH
The stove in this example is a Lennox Whitfield Optima 3 which is a very well designed wood pellet stove. The voltage specs are similar for the other 3 speed newer Lennox Whitfield wood pellet stoves.
The issue is the fire door window is getting dirty and sooty very quickly.
Therefore after making sure the stove was clean, the exhaust blower and control panel, after checking and replacing gaskets is the next item to check.
Many stoves change the speed of the exhaust blower for each heat level so checking these speeds is the last step to assure it is working properly.
Here are some steps I put together for testing.

1. Remove the exhaust blower to clean and lubricate and do the spin test.
__a. Clean with a wire wheel and putty knife under the impeller blades.
__b. Lubricate blades with dry moly and lubricate the motor shaft and bearings with Marvel
____Mystery oil or Synthetic Bearing Oil.
__c. Do the spin test by hand to see if the impeller blades slowly wind down and listen very
____carefully for metal to metal noise which means the bearings are wearing out.
See video on spin test here

2. Bench test 121.9 VAC
Apply 120 VAC to the exhaust blower on the bench to assure the blower is working properly at full speed
See pic 9

3. Speed test in the wood pellet stove
Install the exhaust blower into stove with a testing jumper for connection to a digital voltage meter.
See pic 8 in for test setup. The molex connectors can be removed and the wires can also be connected to stoves with spade clips for the same speed testing.
In this case one of the latches on the ash pan was unlatched which caused the problem.

Any Comments?
Pic 0 - Pellet Stove under test
Pic 1 thru 6 - cleaning & lubricating the exhaust blower. Use a putty knife under the blades & a wire wheel and white aluminum oxide blasting to clean the blades.
Pic 7 - Lubrication Hole on Exhaust Blower
Pic 8 - VAC meter with connectors (speed test setup)
Pic 9 - Bench testing @ 121.9 VAC
Pic 10 & 11 - Low Heat Level - Blower Voltage from Control Panel = 96.1 VAC
Pic 12 & 13 - Medium Heat Level - Blower Voltage from Control Panel = 113.5 VAC
Pic 14 & 15 - High Heat Level - Blower Voltage from Control Panel = 124.8 VAC

For Older Whitfield Wood Pellet Stoves with 5 Heat Levels the Voltages are as follows:
Heat Level 1 - 70 VAC
Heat Level 2 - 76 VAC
Heat Level 3 - 79 VAC
Heat Level 4 - 85 VAC
Heat Level 5 - 107 VAC
Thanks to SnowyRivers for the above Information.
Note: During the startup cycle, the exhaust blower voltage remains the same and cannot be changed until the run cycle.

In the case above if the voltages are not like the ones shown, then the control panel may have to be replaced. If the exhaust blower is not turning as it should or noisy then it may have to be replaced


  • 0-LennoxWhitfieldOptima3.JPG
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  • 1-DirtyExhaustBlower.JPG
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  • 2-WireWheelExhaustBlower.JPG
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  • 3-EaxhaustBlowerBlastingClean.JPG
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  • 4-CleanedExhaustblower.JPG
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  • 5-LubedExhaustBlower.JPG
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  • 6-Cleaned&LubedExhaustHousing.JPG
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  • 7-ExhaustBlowerLubricationHoleYA.jpg
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  • 8-DigitalTestMeterSetup.JPG
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  • 9-ExhaustBlowerBenchTesting.JPG
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  • 10-LowHeatLevelVoltage.JPG
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  • 11-LowHeatLevel.JPG
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