Residence HVAC guys. Need help.

[GSD-Keegan]

Another question for HVAC guys please and thanks. A/C compressor condenser unit, lines and evaporator were replaced about two years ago. 3 months or so after installation noticed an intermittent issue. Notified installer but he never showed up. Last year again notified him and he never showed up. Being an intermittent issue I also forgot about it. This summer season, noticed the same issue. On start up, the outside compressor unit will buzz, but not start. It will do this about 5 times, then time out. Sometimes will start normally after this issue. It starts normally on a frequent basis, intermittently it will do this fail to start.
Installer has shown up twice this year attempting to fix issue, after I sent him a video. 1st visit capacitor was changed. 2nd visit relay contacts were changed. No oil leaks were found in compressor area and system pressures were fine….so I was told. I tested double pole circuit breaker with an ohm meter and it tested fine. I cleaned the quick disconnect outside, wasn’t very dirty, and tightened all connections. I get the impression from the buzzing noise that it may be trying to start on 110v instead of 220v.?? Or the compressor motor has a dead spot, or the compressor is somehow staying in high pressure causing an overload on start? Any ideas? I was thinking I might replace circuit breaker…but hate to just throw parts at it

 

[Donystoy]

I would suspect the contactor or the capacitor. I have seen capacitors installed improperly in the past. Find out what capacitor is required ie. 5uf for fan and 40uf for the compressor. Been an almost new system it could also be a loose connection in the compressor wiring. Unusual that a new system would have a bad relay (contactor) or capacitor.

 

[Speed25]

I've had a replacement capacitor that was defective. The replacement's replacement fixed things back up with no issues in the years since. Either way, after only two years, aren't you still under warranty?

 

[GSD-Keegan]

Thanks guys for both your responses. I’m struggling with the fact that one capacitor was already replaced about 2 months ago, and the contactor was also replaced about a month ago. ….neither of which solved the problem.
As far as I’m concerned I’m under warranty because I notified him a few months after the install. I will have to read up again. I do remember I had 10 yrs on the evaporator.

 

[Russell King]

Thanks guys for both your responses. I’m struggling with the fact that one capacitor was already replaced about 2 months ago, and the contactor was also replaced about a month ago. ….neither of which solved the problem.
As far as I’m concerned I’m under warranty because I notified him a few months after the install. I will have to read up again. I do remember I had 10 yrs on the evaporator.

You may get some information from this link that will give you ideas on why it is not starting reliably.

I would NOT install the kit being described on a two year old unit but rather eliminate the source of the problem. You may want to get the voltage drop checked at the compressor to see how that is holding up. That would be the most likely reason to me.

When should I add a 'hard start' to my central air conditioner?

<p style=

www.acdirect.com

 

[DustyRusty]

Also, check your homes electrical connections. I had a neighbor that was having problems with his air conditioning unit, and after much checking by the technician he found that there was a problem with one line coming into the home from the pole. I don't know if it was a bad connection or a bad transformer on the pole, but the utility fixed it and all his problems went away.

 

[GSD-Keegan]

Thanks Russ for the link. I read it and the symptoms pretty much describe what my unit is doing.
And, Dusty I was thinking electrical as you which made me ponder the circuit breaker…which will have two sets of contacts…with one set maybe causing a bad intermittent connection?? I have other 220v stuff that works fine, so I’m kinda discounting the feed from the pole to my service panel. But hey, who am I…lol
Gonna call the last service man I had on Monday….but I think he’s at a loss as well.

 

[Daren Todd]

Another question for HVAC guys please and thanks. A/C compressor condenser unit, lines and evaporator were replaced about two years ago. 3 months or so after installation noticed an intermittent issue. Notified installer but he never showed up. Last year again notified him and he never showed up. Being an intermittent issue I also forgot about it. This summer season, noticed the same issue. On start up, the outside compressor unit will buzz, but not start. It will do this about 5 times, then time out. Sometimes will start normally after this issue. It starts normally on a frequent basis, intermittently it will do this fail to start.
Installer has shown up twice this year attempting to fix issue, after I sent him a video. 1st visit capacitor was changed. 2nd visit relay contacts were changed. No oil leaks were found in compressor area and system pressures were fine….so I was told. I tested double pole circuit breaker with an ohm meter and it tested fine. I cleaned the quick disconnect outside, wasn’t very dirty, and tightened all connections. I get the impression from the buzzing noise that it may be trying to start on 110v instead of 220v.?? Or the compressor motor has a dead spot, or the compressor is somehow staying in high pressure causing an overload on start? Any ideas? I was thinking I might replace circuit breaker…but hate to just throw parts at it

Replace the capacitor. I had a similar issue with mine.

Came out.and all I was getting was a buzzing noise. AC guy came out, replaced the capacitor.

After seeing how easy it was to replace, I'll do it myself the next time.

 

[DustyRusty]

Possibly high resistance in one of the cables supplying the unit. I don't know if you have any aluminum wiring in the system, but I do know that sometimes the connections with aluminum wire can become problematic. My a/c units are 12 gauge romex from the breaker box to the outside service box. From there to the condensers is nonmetallic conduit with individual wires. To be honest, I don't know if the installer used copper or aluminum in my installation, but that is something that you can have checked. My intuition is that it is stranded copper wire because there would be no reason to use a heavier wire than the wire coming from the electrical panel.

 

[Vlach7]

I would try a temp rewire to a large gen to see if you still have the problem to troubleshoot the house electrical.

 

[GSD-Keegan]

Pretty sure mine is 14/2. Romex (X2). Copper.

I do have 2 capable portable generators……only problem is the issue is so intermittent. Might go a week without hearing the problem…..then will hear it act up two or three times in one day!

 

[DustyRusty]

Check your connections at both ends of the supply and the condenser. Preferably with a digital meter that will hold the readings until you release them. 14/2 is kind of light for an a/c unit. I used 12/3 so I have 2 hot, 1 neutral, and 1 ground. Each unit has its own disconnect and one unit has to have a 110 GFI service outlet. This was code 7 years ago when I installed it.

 

[Poohbear]

what size is the unit ? If its 2 tons are greater that 14/2 may be part of your problem . Also if you decide to get a new run capacitor use a cap rated at 440 volts instead of the factory 370 volt.

Does the thermostat or condenser have a 5 minute delay before it can restart ? could be trying to start before the pressures equalize causing compressor overload to open.
For expenses I could come take a look

 

[DustyRusty]

what size is the unit ? If its 2 tons are greater that 14/2 may be part of your problem . Also if you decide to get a new run capacitor use a cap rated at 440 volts instead of the factory 370 volt.

Does the thermostat or condenser have a 5 minute delay before it can restart ? could be trying to start before the pressures equalize causing compressor overload to open.
For expenses I could come take a look

It is a very long distance from Texas to Ontario, Canada......
Poohbear
Active member · From Gilmer,Tx,United States

GSD-Keegan
Well-known member · From Ontario, Canada

 

[GSD-Keegan]

Thanks everyone for your help. I will try to determine the size of the unit today and post back. 20 yr old unit ran fine on the wiring. It developed a leak as par for the course. I’m wondering now if a larger unit was installed and the wiring is insufficient as Pooh has informed me.

 

[The Evil Twin]

Thanks everyone for your help. I will try to determine the size of the unit today and post back. 20 yr old unit ran fine on the wiring. It developed a leak as par for the course. I’m wondering now if a larger unit was installed and the wiring is insufficient as Pooh has informed me.

More important than the size (capacity) is the MCA, RLA and LRA of the motors. If you can post a photo of the data plate that would be helpful in determining the size and electrical ratings. It should look something like this:

In this example, it is a 2.5 ton/ 30k btu unit. The minimum circuit ampacity is 17.9 amps. The 14 ga wire is barely sufficient for this install, but legal here (80% of 17.9 is less than the rating for 14 ga wire DEPENDING on how long the run is).
If they replaced like for like capacity wise, the unit should have a lower MCA than your previous one.

 

[forceten]

Install a hard start kit. Sort of like a booster for the capacitor. If not its gonna be a new compressor me thinks.

 

[Poohbear]

It is a very long distance from Texas to Ontario, Canada......
Poohbear
Active member · From Gilmer,Tx,United States

GSD-Keegan
Well-known member · From Ontario, Canada

just mail me a CC and will get on the road. Just got to put my tools in the RV as Im already hooked up.

 

[Russell King]

Since it seems to be an (annoying) intermittent problem that sort of indicates that it may be a voltage issue and at your incoming power. You might want to see if your power company is “struggling“ to maintain the power in your area and getting too much drop.

 

[GSD-Keegan]

Thanks to everyone for trying to help me with this issue. I am learning something! And I stand corrected. Did more investigating and I do have 12 gauge wiring feeding the quick connect box outside. This is running thru a double 20 amp circuit breaker. The run is about 55 feet at most.

If my figuring is correct, I also have a 2.5 ton unit going by the model number. Please correct me if I’m wrong…
Power consumption seems to be lower than the specs Evil posted. I do notice on the specs the max breaker size is 15 amps, compared to my 20.
DONT this this would cause my issue tho..??

Here is a pic of specs on my unit. Back to the thinking caps??
Thanks again everyone