u/1d0wn5up

I am looking for some diagnostic advice on an older American Standard AC unit paired with a Nest thermostat. My setup does not have a C-wire. To bypass a historical issue where the Nest wouldn't reliably trigger the indoor blower, I have successfully run the system for the past couple of years with G and Y jumped at the primary control board.

The Incident: Upon starting the AC this season, the condenser kicked on but the indoor blower did not. I found my jumper wire had been knocked loose. When reconnecting it, I made an error and accidentally jumped G to RT instead of Y. Upon powering up the system, this immediately fried the primary control board.

Current Status: I swapped in a known-good, older spare primary control board and wired it correctly, restoring the proper G to Y jumper. Now, when the system calls for cooling:

• The board relay clicks. • The blower motor sounds possibly like it tries to start for maybe a split second, but ultimately fails to spin. • Followed by the Nest thermostat immediately going into a 2+ minute lockout delay.

My Questions: Assuming the G to RT miswire potentially backfed 120V into the low-voltage circuit, I am trying to isolate the downstream damage so I can repair this myself.

1. What is the next most likely component that got fried? (e.g., the Nest baseplate, the blower motor itself, the run capacitor if this motor has one, or further down the line on the outdoor unit?)

2. What specific multimeter testing sequence should I follow to pinpoint the failure before I start buying replacement parts? I’m leaning towards the nest itself to start there since the G wire is what got backfed the 120volts.

Any guidance is greatly appreciated, as I am trying to keep repair costs down right now and just don’t have the funds to call someone out it’s also been 90+ degrees here. Lastly if the blower motor ends up bad what is a good replacement on these older units? I appreciate yall.

Ps - the first pic is how it’s currently wired.

I’m currently renovating an upper floor in a detached garage and need to address skylight leakage before finishing up with the painting and trim work. The roof is approximately 25+ years old (1999 install). Historically, there was some leaking and staining from ice dams roughly 10+ years ago, followed by many years of no leaking that were evident to the eye and touch. This past winter, however, severe ice damming caused active leaking in one of 3 skylights again as expected that it would come back.

I’ve received three professional opinions and am looking for some advice on the best path forward as each one’s a bit different..

Option 1: Full Replacement. New roof and three new skylights. Clearly the best long term solution, but I’m hoping if possible to squeeze 3-5 more years out of the current shingles and or skylight if possible.

Option 2: Partial Replacement ( Roughly $6k). Replace all three skylights, install new flashing/Ice & Water Shield, and patch in new shingles around the units.

Option 3: Targeted Remediation ($1,700). Pull shingles, re-flash the existing units, and extend the Ice & Water Shield higher up the roof deck to mitigate future damming. The units themselves would not be replaced.

My Dilemma:

Removing the skylights completely isn't an option due to a lack of natural light in the room. Short of replacing the whole roof and skylights , Is the $6k investment in Option 2 justifiable given the age of the overall system? I’m concerned about over-investing in a high-cost stopgap when those funds might be better spent on a total tear-off and replacement in the next few years so long as option 3 can buy us some time until then.

With that said - is option 3 a realistic temporary stop-gap or is re-flashing a unit of this age a lost cause? Based on the intermittent nature of the leaks, does this sound like a failure of the flashing/underlayment due to pressure from the ice dams, or have the skylight unit seals themselves just reached the end of their life? It was mentioned that when the roof was installed they might have not ran ice and water all the way up to the skylights and be causing part of the issue.

Just putting this out there to hear from some other professionals on what they think..As I’m not trying to make the wrong choice but if reasonable id like to get a few more years out of this roof.

I’m currently renovating an upper floor in a detached garage and need to address skylight leakage before finishing up with the painting and trim work. The roof is approximately 25+ years old (1999 install). Historically, there was some leaking and staining from ice dams roughly 10+ years ago, followed by many years of no leaking that were evident to the eye and touch. This past winter, however, severe ice damming caused active leaking in one of 3 skylights again as expected that it would come back.

I’ve received three professional opinions and am looking for some advice on the best path forward as each one’s a bit different..

Option 1: Full Replacement. New roof and three new skylights. Clearly the best long term solution, but I’m hoping if possible to squeeze 3-5 more years out of the current shingles and or skylight if possible.

Option 2: Partial Replacement ( Roughly $6k). Replace all three skylights, install new flashing/Ice & Water Shield, and patch in new shingles around the units.

Option 3: Targeted Remediation ($1,700). Pull shingles, re-flash the existing units, and extend the Ice & Water Shield higher up the roof deck to mitigate future damming. The units themselves would not be replaced.

My Dilemma:

Removing the skylights completely isn't an option due to a lack of natural light in the room. Short of replacing the whole roof and skylights , Is the $6k investment in Option 2 justifiable given the age of the overall system? I’m concerned about over-investing in a high-cost stopgap when those funds might be better spent on a total tear-off and replacement in the next few years if option 3 can buy us some time until then.

Is option 3 a realistic temporary stop-gap or is re-flashing a unit of this age a lost cause? Based on the intermittent nature of the leaks, does this sound like a failure of the flashing/underlayment due to pressure from the ice dams, or have the skylight unit seals themselves just reached the end of their life? Just putting it out there to hear from some other professionals on what they think..

Currently building a in-law apartment above the detached garage. Upstairs there are 3 skylights within the room. They have each leaked at one point causing the staining you see in the pictures. Most of the staining occurred during a bad winter about 8+ years ago and after that winter they never leaked again but we never fixed the stain marks as the upstairs wasn’t used much. Fast forward to this winter - it was a rough one and a ton of ice dam build up occurred again. That caused one of the three to leak again. Now that we are renovating the upstairs and getting ready to have things painted we have got quotes to address the leaking issues prior to painting. Most roofers seemed to agree it was from the ice dam buildups. However each of them gave different options for fixing the issue at hand and how they think the water made it way in.

The first guy recommended a whole new roof and three new skylights. I understand that is the best overall option to do things right. I’m still crunching numbers to see if I can afford going that route. I’m also exploring these other fixes they mentioned..

Second company said they seems to think the leaks were coming from damaged seals on the windows and he would recommend three new skylights as well as ice and watering and basically patching in a new section of roof on each skylight. This was around $6k

The third guy recommended a new roof in the near future as well but gave a back up option and said that he could just reflash the current skylights as that’s where he believes the water is coming in from and mentioned that they might not have ran ice and water up high enough years ago when this roof was done. He said that would buy us some more time as the current roof is towards the end of its life and should be replaced in the next 5 years but for now it’s a cost effective option to address the leaking and give us some time to get ready for a new roof to be put on. This would be around $1700

I’m having trouble on what route to go and looking for some advice - keep in mind cost is part of the issue and I’m not fully ready to put a roof on it yet unless absolutely needed. I also don’t know if it’s worth putting new skylights in and patching it all in - at that point if I go that far it seems it might make sense to just do the whole job because in the near future I’ll still need a new roof.

I’m hoping to buy myself a few more years with this roof and have them reflash the current skylights I just don’t want to shoot myself in the foot if that won’t fix the leaking since some say it could be from the flashing and others say it’s from the seal on the window itself and others say they don’t know exactly but are just going by the life span of the roof and skylights. Like I mentioned the water intrusion only happened two winters over the last 10yrs that both had bad ice damn build up so I want to lean towards the flashing being an issue but I don’t know enough when it comes to roofing.

With that said - If I could just get rid of the stupid skylights completely I would but unfortunately there isn’t much natural light upstairs. If anybody with some experience could weigh in on this it would be much appreciated since I’m getting different options on how to fix it and just want to educate myself as much as possible on the different fixes.

Appreciate any advice!