Lennox A/C issue... need help

Newer Lennox ac unit EL18xcv Elite series 2 stage. Shut unit down for the season. Pulled bar out of outside box and turned off circuit breaker. While putting on the cover I noticed a clicking noise occurring in unit..... happens every 3-4 minutes with reasonable regularity. Only way to stop it is disconnect red thermostat wire that comes out from the furnace board. What is clicking and why????
Thought I should add.... there are 4 thrmo wires going to the unit. The red one is the only one that is "hot"

 

Welcome to the forums.

I'd get the service tech to check it out. That unit is very sophisticated and expensive to repair.

From service manual......
When utilizing a two-stage conventional 24VAC non-communicating thermostat, four wires are required to control the outdoor unit (R, C, Y1 and Y2). Refer to the EL18XCV field wiring diagram for a conventional 24VAC non-communicating 2-stage thermostat.

When utilizing a single conventional 24VAC non-communicating thermostat, three wires are required to control the outdoor unit (R, C, and Y1) and Y1 is jumpered to Y2 in the outdoor unit. Note that the published performance data is based upon the use of a two-stage thermostat. Refer to the EL18XCV field wiring diagram for a conventional 24VAC non-communicating single-stage thermostat.

Lennox EL18xcv manual - pdf

 

Yes this a/c unit is ALOT more complicated than the single speed units. Since utility costs are going so high I thought it made sense to get a more efficient setup. Kind of regretting it now. Quite a few expensive components in the cond unit. Trying not to call & pay for a service guy till absolutely necessary. Going to try a new contactor... they are pretty cheap. I'm kind of afraid that won't fix the random clicking sound tho, but I'll try it anyway. Worst case... I'll wind up w a spare contactor. It's just strange it does that with all the power being off except the 24v from the red wire??? These units have a control board in them like the furnace does so maybe that's it? I'll try the contactor 1st

 

The condenser has its own control board and runs on 24vac.
Knowing whether your system is legacy(normal) wired or is a communicating system is important.

 

I would open the panel and see if it is spitting out a loss of 240 volt power error code along with the clicking noise.

Probably is.

 

What would that error code mean? And accordingly do what to resolve it? I did replace the contactor yesterday.... in the process of doing that I found that the ground wire coming from the house was VERY loose in the lug that's mounted to the chassis, I could've pulled it out it was so loose! Tightened it up real good. Not warm enough out to run it right now. I'm definetly curious what the code means. Really appreciate the help!
By the way, I use a Ecobee thermostat. Wouldn't think that would matter in this senario or would it?? What I mean is at this time none of the other Stat wires are hot... just the red one & the clicking continues! There is no 110/220 going to the unit either right now. Crazy! I'd love to solve this. Thanks again.

 

Houston said it would be a loss of 240v to the condenser.

You're telling us that there is no 110/220 going to the condenser.
Why is that.... there should be 240v going to the condenser at all times.

Just re-read your first post.... the pullout needs to be left in during the winter.

 

I've got the pullout pulled because it seems silly to have the compressor heater activated for the 5 winter months. Seems like a real waste of energy! I've always done that every year with my previous single stage Lennox ac unit. Of course as discussed earlier this newer unit has way more electronic "junk" in it. Guess my next step needs to be restoring the power to the unit & see if the clicking stops. I'll let you know what happens. Again I appreciate the thoughts & ideas. 😀

 

Well fellas.... that did it. Restored power to the unit and no more clicking sound!!! I mean yes, I'm VERY pleased that it worked. Now I can stop my obsessive thinking about it. But I find it very strange that the unit was engineered that way! In any event I would not have ever tried that as a solution without your help. Thank you - Thank you! As a side note are you guys hvac techs to be able to come up with these ideas!? Thanks again.... my mind is at rest!!