All installations and services must be performed by qualified service personnel.
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| OMD/GMD TROUBLESHOOTING FLOWCHART | ||
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| Note: Check diagnostic code through view port | ||
Set thermostat subbase to "HEAT" |
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| prior to removing doors. | ||||
Does thermostat make contact? |
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| No |
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| Is room temperature |
| Yes |
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| Wait for room air to cool. |
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| above 90 deg. F? |
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Yes | No | |
Yes | ||
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Is room temperature above | Turn thermostat setting | |
thermostat setting? |
| above room temp. |
No |
Replace thermostat
Does a "call for heat" initiate an ignition cycle?
Yes
No |
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| Yes |
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Is the power switch "off"? |
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| Turn power |
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| switch "on". |
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| No |
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| No |
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| Check input power. Reset circiut | |||
| Is there 120 VAC |
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| breaker, or replace blown fuse in | ||||||
| across lines L1 & L2? |
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| disconnected switch. | |||||
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Yes |
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| Wait for furnace to cool. | |
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Is the control transformer | No | Have either of the | Yes | Look for cause(s) of high | |
limit activation,eg. low | |||||
(GMD) or oil primary control |
| high limit thermostats |
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| airflow, | |||
(OMD) receiving 120 VAC? |
| activated? |
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| blocked flue,etc.. | |||
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| Correct any | |
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| abnormal conditions. | |
Yes |
| No |
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| With power on,measure |
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| voltage across the aux. |
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| high limit thermostat N.C. |
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| contact to L2. If not 120 VAC, |
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| replace aux. high limit |
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| thermostat. Else,replace |
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| high limit thermostat. |
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