Connecting the CoolCloud app when the 3-digit code is not visible

What is going on

The CoolCloud app normally pairs using the three-digit access code you read through the sight glass on the control. If you cannot see all three digits, for example the glass is dim, the LED is hidden by the cabinet or the code never displays, there is a fallback that uses the thermostat as the key. It is a timed sequence, so read the whole thing before you start and have someone at the thermostat if the furnace is far from it. Do it with the phone inside Bluetooth range of the furnace, because access is only granted when all three steps finish while the phone is connected.

Likely causes

• Sight glass is dirty, scratched or at a bad angle so the digits cannot be read
• Control is showing no code because of a power or board problem, so check that first
• Technician has no line of sight to the board in a tight closet or basement install
• A previous pairing attempt timed out and the sequence needs to be restarted

Check in this order

1. Confirm the furnace has power and the control is alive before starting, since a dead board will never grant access
2. Set the thermostat fan to Auto (not ON) and remove any heat or cool call. Finish step 1 within 5 minutes of starting
3. Give any 24VAC call (cool, heat or fan) from the thermostat within 8 minutes after step 1
4. Remove the call from step 2 within 1 minute after it was given. This window is short, so keep your hand on the thermostat
5. Stay in Bluetooth range during all the steps and watch the app for the access confirmation
6. If the app does not confirm, wait for the timers to expire and start over from step 1 rather than guessing where you were

More furnace guides

• Airflow lower than demanded, furnace runs on low stage when high stage is expected
• Alternate combustion air opening (upflow or horizontal)
• Alternate vent/flue location (upflow or horizontal left)
• Annual inspection checklist
• Auxiliary limit control (location and purpose)
• Auxiliary limit switch open (blower compartment)