Indoor Options Module Communication Troubleshooting
Summary:
Options Board com voltage is 4.5 to 3.25 VDC, pulsing 30 times a minute.
Measuring at Options Board or downstream of the problem:
IMC - open – Options Board LED 5 off, LED 6 off.
(IMC + to IMC -) 4.2 VDC to 3.6 VDC.
(IMC + to Ground) 4.7 VDC to 4.3 VDC.
(IMC – to Ground) .49 VDC to .47 VDC.
IMC + open – Options Board LED 5 dim flicker, LED 6 dim flicker.
(IMC + to IMC -) .7 VDC to .3 VDC.
(IMC + to Ground) .97 VDC to 87 VDC.
(IMC – to Ground) .91 VDC to .1 VDC.
Wires Crossed – Options Board LED 5 on steady, LED 6 off.
(IMC + to IMC -) -4.7 VDC to -.3 VDC.
(IMC + to Ground) .75 VDC to .1 VDC.
(IMC – to Ground) 4.7 VDC to 4.2 VDC.
Other LED info – IMC wires shorted together or both open, LED 5 and 6 off.
Jump to Indoor Options Module Pinout / LEDS Article
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WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.
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