AC Question

[Wizard29]

Weird problem with the AC at the river house...I'm not out there at the moment and stuck at home with my broken leg deal. This shit always has to happen at the worst time.

Nest thermostat that has been reliable for over a year keeps going offline. I had my friend go look at it and it reports "no power", which means there is no power on the AC system.

My friend can go outside and cycle the 50A breaker in the house panel and the system starts up again. The breaker does not appear to be tripped. Runs for about a day and goes off again. Cycle the same breaker and the system comes back on.

Is this likely a case of a weak breaker or something in the AC system itself that is tripping off and needs to be reset by interrupting power and bringing it back again? I've never heard of an AC board or something needing a power reset to work again, but I guess it's possible?

 

[ChrisV]

Ours was doing this at home and I replaced the capacitor and its fine. I'm not an expert at all... Maybe an expert can chime in.

 

[Nordie]

I'd look at getting it serviced, replace the capacitor(s), possibly the contactor.

Last weekend my contactor burned up and messed up some wires due to old loose connections. Came home from the lake to no AC. By the time me and my dad got it fired up it was 90 degrees in the house.

Lastly take that Nest and toss it in the garbage and buy a Honeywell instead.

 

[ChrisV]

I'd look at getting it serviced, replace the capacitor(s), possibly the contactor.

Last weekend my contactor burned up and messed up some wires due to old loose connections. Came home from the lake to no AC. By the time me and my dad got it fired up it was 90 degrees in the house.

Lastly take that Nest and toss it in the garbage and buy a Honeywell instead.

Which Honeywell do you recomened?

 

[TrollerDave]

If there is something wrong with the unit, it can go into a hard lockout and only be reset by cycling the power. If the problem still exists, it will hard lockout again. This is at the AC unit control board. But, the unit should still have power. I’ve never dealt with nest and am not sure how what can result in “No Power” at the tstat.
You might need to get a tech to check it out.

 

[Wizard29]

I'd look at getting it serviced, replace the capacitor(s), possibly the contactor.

Last weekend my contactor burned up and messed up some wires due to old loose connections. Came home from the lake to no AC. By the time me and my dad got it fired up it was 90 degrees in the house.

Lastly take that Nest and toss it in the garbage and buy a Honeywell instead.

Going to be out there next week, so I might see if I can schedule an AC guy to come out while I'm there.

I did buy the Honeywell RTH6580WF wifi thermostat in case the Nest unit is the problem, but I don't think this is a thermostat issue since resetting the breaker seems to do the trick. The Nest has worked well for over a year...

 

[TrollerDave]

Going to be out there next week, so I might see if I can schedule an AC guy to come out while I'm there.

I did buy the Honeywell RTH6580WF wifi thermostat in case the Nest unit is the problem, but I don't think this is a thermostat issue since resetting the breaker seems to do the trick. The Nest has worked well for over a year...

Any issues with the wifi?

 

[Wizard29]

Any issues with the wifi?

Not at all. I have cameras everywhere and they are all working.

What sort of issues can cause the hard lockout you described? Unit fires right back up no problem after the breaker is cycled.

 

[NicPaus]

I would bring a new breaker just in case when you head out.

 

[Nordie]

Which Honeywell do you recomened?

I really don't have a recommendation for which Honeywell to use. Mine is like 12 years old and still connects to wifi no problem. I've only heard of the nest horror stories, and on Sunday my dad confirmed those horror stories. I also might be a little biased as my grandma retired from Honeywell as she used to soldier the boards in an Illinois facility before Honeywell left Illinois.

 

[Nordie]

Going to be out there next week, so I might see if I can schedule an AC guy to come out while I'm there.

I did buy the Honeywell RTH6580WF wifi thermostat in case the Nest unit is the problem, but I don't think this is a thermostat issue since resetting the breaker seems to do the trick. The Nest has worked well for over a year...

I don't think it's your thermostat either, seems like AC units are a little more simple than most think. I bet your issue is a relatively simple fix with having the right person there to diagnose it.

 

[DLC]

My garage AC stopped working about 8 pm on July 3 … I was like OH crap ! We had some friends coming in for Independence Day boating

After doing some discovery - Turns out the Electrical Disconnect Heated up and it distorted some of the inside plastic & I popped a fuse.
AC worked fine and everything was good earlier in the day

I had extra fuses and a cap on hand to get me up and running thru the holiday
and
Then had Mission Accomplished out Friday morning

They swapped out the discount and checked the AC everything was good!! Disco went bad…

Ethan & his Minion were great! I forgot the Minions name but they got some lunch money and had a few laughs at my expense

it sure is great to be able to txt someone and have them respond in a timely fashion on a Holiday !

I can’t thank
Mission Accomplished enough !!


@Wizard29

Could be an electrical issue - bad contact, loose connection, broken T state wire in the AC unit, a disconnect blade contact could have excess gap

 

[TrollerDave]

Not at all. I have cameras everywhere and they are all working.

What sort of issues can cause the hard lockout you described? Unit fires right back up no problem after the breaker is cycled.

A hard lockout is a safety which basically keeps the unit from running because it has detected a problem, could be electrical or refrigerant related like hi or low pressure. A/C’s have safety sensors for diagnostic and protection. If a problem is sensed, for example, low pressure, the board will turn the unit off, but let it start in case it was something temporary. If it senses and cuts out maybe 3 times in 10 mins, it will go into a hard lockout mode to let you know there is an issue. There is usually an LED on the circuit board that will flash a code that will tell you why it is locked out.

I’m not saying this is the problem, but if you’re a/c fixes itself by cycling power and eventually goes off again, the lockout is a possibility.

 

[702sandman]

We have a builder that has us install nest stats on every house and this has happened several times now where the stat says no power. out of probably 300+ nest stats we have installed we have had maybe 5-6 of them needing to be replaced with this same issue. Resetting the breaker is just resetting power to the system. I’d look at the Honeywell T10 as a alternative

 

[SoCalDave]

Yeah I would ditch the nest as well.
I've installed several of the Honeywell T5 TS over the years and they have been flawless.

 

[dezertrider]

I would stop cycling power to the unit. Like others have said it may have a lock out that is protecting it from killing your compressor. The Honeywell T4 and T10 are great thermostats. I also like the Ecobee. They all work great.

This Havasu heat absolutly destroys capacitors in peak season. Some we have replaced earlier this year have allready died. We created a special Mohave Heat kit to solve this problem. The cheap capacitors were causing to many callbacks so we found a combination of high quality parts that work well here in Havasu

 

[joecfd1]

I would stop cycling power to the unit. Like others have said it may have a lock out that is protecting it from killing your compressor. The Honeywell T4 and T10 are great thermostats. I also like the Ecobee. They all work great.

This Havasu heat absolutly destroys capacitors in peak season. Some we have replaced earlier this year have allready died. We created a special Mohave Heat kit to solve this problem. The cheap capacitors were causing to many callbacks so we found a combination of high quality parts that work well here in Havasu

PM'd you

 

[stephenkatsea]

FWIW - Recently our very new 4T unit quit working. Fortunately, we realized it was just low batteries in the wi-if capable Sensi thermostat.

 

[Flying_Lavey]

Not at all. I have cameras everywhere and they are all working.

What sort of issues can cause the hard lockout you described? Unit fires right back up no problem after the breaker is cycled.

Ditch the Nest. I cannot recall how many horror stories I have heard with them. So many people I know that have installed them have taken them out shortly thereafter. The residential line of Honeywell T'stats are not what they used to be. About 6 years or so ago they split the residential consumer grade products into its own line (these typically have "Residential" stamped on them somewhere) and they have not been NEARLY as reliable as the commercial or professional lines. The T series and TH series are the commercial and professional lines that are still very reliable and made of good quality.

I would also suggest a Venstar, however their WiFi connections don't seem to be as stable and reliable as the Honeywell.

I don't have any experience with the Ecobee or Sensi lines so I wont say one way or another on them.

 

[dezertrider]

Ditch the Nest. I cannot recall how many horror stories I have heard with them. So many people I know that have installed them have taken them out shortly thereafter. The residential line of Honeywell T'stats are not what they used to be. About 6 years or so ago they split the residential consumer grade products into its own line (these typically have "Residential" stamped on them somewhere) and they have not been NEARLY as reliable as the commercial or professional lines. The T series and TH series are the commercial and professional lines that are still very reliable and made of good quality.

I would also suggest a Venstar, however their WiFi connections don't seem to be as stable and reliable as the Honeywell.

I don't have any experience with the Ecobee or Sensi lines so I wont say one way or another on them.

We recently had a customer log into his Nest thermostat and turn his Havasu AC on while he drove out for the weekend. When he go there his house was 120 degrees inside

The Nest decided to heat and now cool the house. Nest is total junk

 

[Flying_Lavey]

We recently had a customer log into his Nest thermostat and turn his Havasu AC on while he drove out for the weekend. When he go there his house was 120 degrees inside

The Nest decided to heat and now cool the house. Nest is total junk

Not to mention the only way it "learns" your schedule is if you walk by it enough within an hour to know that you are home that hour.

But they are round and pretty soooooo..... the women pick them. lol!

 

[Ace in the Hole]

FWIW - Recently our very new 4T unit quit working. Fortunately, we realized it was just low batteries in the wi-if capable Sensi thermostat.

learned this lesson last year lol. Great t-stat besides that issue.

 

[Flying_Lavey]

FWIW - Recently our very new 4T unit quit working. Fortunately, we realized it was just low batteries in the wi-if capable Sensi thermostat.

learned this lesson last year lol. Great t-stat besides that issue.

If you have a WiFi T'stat, power it from the unit. Worse case you can use an Add-a-wire kit if your wire doesn't have enough conductors in it. No reason not to.