Carrier Greenspeed inverter fault

KBrianAugust 22, 2014

Hi -

I have my dealer involved, but no good answer yet. They are not familiar with the fault and their tech expert on the system wasn't available.

My 3 ton greenspeed system is giving the following faults -

75 - Inverter Temp Out of Range Event (lots)
88 - Inverter Temp Lockout (twice so far)

Happens on hot days. System is 10 months old.

System is cooling fine. Line pressures are fine. Inside static pressure is fine.

Any hints?

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What other details can you provide regarding your system and installation, such as, fan coil model and thermostat model?

Have you purchased the 10-year extended warranty?

EVERYONE buying Greenspeed SHOULD buy the 10-year extended warranty from Carrier! I would NOT want to neither own one nor sell one without the 10-year warranty. While I like the theory of Greenspeed, for me personally the jury is still out. IâÂÂll have a better idea in 1-yearâÂÂs time.



    Bookmark   August 23, 2014 at 12:16AM
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Extended warranty purchased. System purchased from carrier listed and NATE certified company as well.


    Bookmark   August 23, 2014 at 5:43PM
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Just curious, why the GreenSpeed HP with an 80% eff furnace?

What is location?

Sorry for your trouble, can't help with fault codes.

How long has this been going on? It would seem that a call to the factory could solve this issue.


    Bookmark   August 23, 2014 at 6:30PM
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We are in a community with monopoly propane piped within the community. Very high prices. Greenspeed gave better heat output, so do not have to hit the propane backup frequently (if at all). Not enough capacity in the electric panel to switch to electric backup.

Austin, TX. Mostly moderate winters, but some very cold days.

Noticed first time on Thursday with the 88 fault generating an automatic mail. When I looked at the stat, then found a few weeks of the 75 faults in the log.

This post was edited by KBrian on Sat, Aug 23, 14 at 21:00

    Bookmark   August 23, 2014 at 6:57PM
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Which model coil did they install indoors, is it a proper match?


    Bookmark   August 23, 2014 at 10:28PM
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I am no expert on this, but I will give the little I have been able to find on the subject.

It seems the inverter is overheating. The inverter takes 230V AC and converts it to 410V DC. Inverters are typically not very efficient so they tend to get hot even when are operating normally. They contain solid state devices so the temperature can't exceed a certain limit. If it does they do not work properly and will eventually be destroyed.

The Code 75 fault is a warning. The Code 88 is a lockout that keeps the inverter from being destroyed. It disables the heat pump for 4 hours so it can cool down. It could be the inverter is malfunctioning and needs to be replaced. There are no serviceable parts. Or it could be something simple like it it getting too much sun exposure.

While you are waiting for the tech to appear, trying putting an umbrella over the condenser and see if that helps the situation. It is doesn't, then the inverter will have to be replaced.

Let us know how this is resolved.

    Bookmark   August 24, 2014 at 10:20AM
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The coil is CNPHP361

The inverter is still overheating when it is shaded in the afternoon (it is on the east side of the house).

Thanks for the tip on the inverter. I *think* the tech that was out was thinking along the lines of something working too hard causing the inverter to work to hard and overheat. Suggested cleaning, replacing outside fan, etc.

I don't really believe that as the machine appears to be in spec on the amps consumed (I have a power monitor on each of my outside HVAC units).

I'll encourage them to get carrier tech support involved since they haven't seen this particular fault yet.

I'll also see if I can get a fan on it or something. I'm surprised there really isn't any airflow (or even heat sink fins that I can see) around the inverter from what I can tell. I do have a thermal imaging camera and found the hot spot on the visible side of the inverter board to be around 140 degrees F.

    Bookmark   August 24, 2014 at 5:01PM
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I would think 140 degree is above the rated specification of the inverter. Your camera will be a good way to verify if any fixes has solved the problem.

There must be several diagnostic checks to pin point the problem. Hopefully they will bring in a Carrier expert and get to the problem quickly.

Keep us posted on how it is resolved.

    Bookmark   August 25, 2014 at 7:58AM
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Just a quick (and hopefully final) update -

My HVAC company came out once - basic trouble shooting. Contacted carrier expert, HVAC company sent a second person out to double check all the system setup. Carrier agreed to replace the inverter, but required a 3rd trip from the tech with pictures/documentation of a few extra (but still basic) parameters. (I think this was actually just busy work, they said they had the inverter in stock at the local reseller but really didn't when they showed up to pick it up).

I didn't push the local company too hard as I have more than one HVAC system in the house and a timeout of 15 minutes wasn't causing problems - except that it needs to be fixed of course! It was mostly only doing the fault 88 15 minute lockout, but did do the fault 75 4 hour lockout last night.


Finally, inverter was replaced today. Looks identical, but several revisions newer per the sticker.

The local carrier distributer indicated that a few inverters have been replaced... and that they are quite expensive :(

I'll watch the fault codes on the stat for a while to make sure it is resolved. One has to go into the menu to see the fault 88. But 75 does show up on the screen and send an email.

Thanks all!

    Bookmark   September 12, 2014 at 6:50PM
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