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My honeywell wifi thermostat went blank while my heater was running yesterday and now my unit just blows air (no heat) and I can't shut off the unit unless I unplug the York furnace. Here's what I've checked so far but still can't figure out what's wrong and the cause of my blank thermostat. Would appreciate if anyone can give their expertise and suggestions, thank you in advance.
1. Changed battery on thermostat (it's powered by c-wire but changed battery just in case).
2. Used multimeter to get a low voltage VAC reading from the wall where my thermostat is installed - no voltage detected.
3. Checked circuit breakers. Not tripped. Checked voltage at breakers, confirmed breakers are working fine.
4. Checked fuse inside furnace - fuse is fine, not blown.
5. Checked furnace transformer. 120v coming in fine and there are two low voltage leads going out. One had 24v reading (#1 in picture) and the other had 0v reading (#2 in picture). Took a reading between #1 and #2 at transformer and got a 25 vac reading. Did not do a resistance test.
6. Terminal strip testing on the board:
R-C gave 1.2 vac reading
R-W gave 1.2 vac reading
7. York furnace light blinking green at intervals of four.
Tempted to just replace the transformer but it seems it is working fine since I can get a 24 vac when testing the two low voltage leads together. Also concerned it might go out again if something is wrong with the system. Also tempted to just put in a new fuse (even though it looks fine) or resort to replacing the thermostat but it's only 4 years old and if I'm not getting power at the thermostat wall, highly doubt the thermostat is the issue.
Does it sound like a bad board?
Appreciate any/all help, thank you so much!
1. Changed battery on thermostat (it's powered by c-wire but changed battery just in case).
2. Used multimeter to get a low voltage VAC reading from the wall where my thermostat is installed - no voltage detected.
3. Checked circuit breakers. Not tripped. Checked voltage at breakers, confirmed breakers are working fine.
4. Checked fuse inside furnace - fuse is fine, not blown.
5. Checked furnace transformer. 120v coming in fine and there are two low voltage leads going out. One had 24v reading (#1 in picture) and the other had 0v reading (#2 in picture). Took a reading between #1 and #2 at transformer and got a 25 vac reading. Did not do a resistance test.
6. Terminal strip testing on the board:
R-C gave 1.2 vac reading
R-W gave 1.2 vac reading
7. York furnace light blinking green at intervals of four.
Tempted to just replace the transformer but it seems it is working fine since I can get a 24 vac when testing the two low voltage leads together. Also concerned it might go out again if something is wrong with the system. Also tempted to just put in a new fuse (even though it looks fine) or resort to replacing the thermostat but it's only 4 years old and if I'm not getting power at the thermostat wall, highly doubt the thermostat is the issue.
Does it sound like a bad board?
Appreciate any/all help, thank you so much!