Blower Temperature Switch Testing
Blower Temperature Switch Testing (cont’d)
Switch Setting
Opens on rise @ approximately 165oF
Auto resets on fall @ approximately 160oF
Cool switch to
below 160oF
Disconnect wire leads to |
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switch. Using | N | Replace switch |
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to the ohms setting. Is there |
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continuity between the switch |
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terminals? |
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Y |
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| N |
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Reconnect wire leads and ob- | Y |
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serve heater operation. Do |
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exhaust gas temperatures |
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rise to or above 170oF with |
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vent connected? |
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N |
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Do switch con- | Y | Replace switch |
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tacts open? |
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N
Switch OK
Common causes for high
exhaust temperature
1.Vent length is below mini- mum allowable
2.Vent diameter not to speci- fication
3.Restricted dilution air inlet
4.Missing or deteriorated flue baffle
5.Gas pressure is out of specification
Page 32
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