Air Conditioning - Heat pump startup noise reduction?

Three months ago, I had a Carrier heat pump installed. (Model #25HBA324A310) One month ago, it quit working. I notified the installer. Six visits, three different techs, three new parts that they said were the problem but weren't, and twenty-nine days later, and a new tech wired in a new thermostat using five wires instead of three (he said) and the heat pump is working again.
But that's just the background. The problem is the heat pump is much louder now than before. I don't mean the motor or air rushing sound. At startup, there's a loud ratcheting, vibrating, humming sound that lasts one to two seconds. It was there before but it was softer and only lasted a half second. My problem is that my neighbors are complaining that the ratcheting sound wakes them at night.
The installer says the sound is normal and acts like he doesn't believe me when I say it's louder than before. I don't know if it's normal or not, or if it's in the range of variations for this model heat pump, but I need a solution.
My neighbors are being very polite about it for now, but if I don't find a solution soon, that could change. Does anyone know if the sound is really normal? If so, can I buy some kind of muffler for the heat pump?

I can only guess since I'm not there. I assume the sound is from the compressor and this sound occurs immediately or shortly after start-up. I am also assuming this unit uses a scroll compressor (I didn't check model #).
One possibility is liquid freon flooding back to the compressor. Scrolls will make a metallic scraping sound when flooded. If this is the case, you may be overcharged or you may need a suction line accumulator (you may already have one). A crankcase heater may or may not help, but heat pumps should have one anyway.

You need a good tech to analyze and investigate. Again this is just speculation and all other possibilities need to be explored.

Maybe other techs on this board will offer their opinion as well.

Ill go with Jim. You do need all the parts inside the unit To help keep the noise down. But if its that bad. Id call Carrier And tell them. They should send a rep. out to look at it for you.

Thanks for the tips.

I once heard a shop table saw jammed by a piece of oak plank. The loud humming sound is similar to the startup noise except the heat pump has an additional metallic element to it.

I've noticed that the sound is less obtrusive and has a shorter duration if the heat pump has been off for awhile. When making a large change in temperature, the heat pump cycles on while the fan is still running. At those times, the ratcheting hum is significantly louder and longer. Does that help in troubleshooting the cause?

I tried going to Carrier's website but every page seemed to be trying to direct me back to the installer.

I'm not sure if the company that installed this heat pump is the right one to talk too. I question the 4 weeks it took them to fix a 2 month old heat pump that they installed.

Is there a good link I can use to cut through the 'bull' and get someone at Carrier who could actually help me?

charlie my man you are in for a long and hard road here most likely. They have messed your unit up probably beyond repair, if it is loud enough to disturb your neighbors in the winter when the houses are buttoned up tight. Now I have heard of problems in the summer when some neighbors leave their windows open but this thing must be way up there in the decibels lol. It will die a slow and painful death and probably pretty darn quickly, you might want to be darn sure that you have everything documented because you WILL have some future problems BIG PROBLEMS. Your best bet is to have a new UNMOLESTED unit installed. You may want to have your lawyer send a letter on over to the company that installed and carries the warranty what you have is totally unacceptable. If I were your neighbor you would probably have a serious refrigerant leak the very first time this piece of crap unit woke me up in the middle of the night LOL

Actually, all joking aside, that was what the first tech found when he looked at the outside unit. He said there was no refrigerant in the unit. He ordered parts. He returned 5 days later, installed the parts, added refrigerant and it didn't work. He left shaking his head saying something about having to ask another tech some questions.

After 2 days, we called to ask when we would be getting some heat. A tech showed up 2 days later. He fiddled with the inside and the outside unit for about an hour then finally gave up. He set the furnace for electric heat and departed.

We called several times to complain that we had paid for a heat pump but were back using our electric furnace, what was the story? 8 days later, another tech showed up. He worked for an hour, cursed the inside thermostat numerous times then departed.

This continued for almost one month then I called (very irate) and demanded they fix the heat pump now or give me my money back and I'd find another company to do the job. Three techs showed up the next day. They drilled holes in the wall where the thermostat was, crawled around in the attic and (they said) ran a new 5-wire control cable to replace the three wire (they said) was in the wall. Strange, I saw the wire they removed and it had more than three wires in the sheath. It looked like 5 or 6 wires.

Anyway, the heat pump started working but it was much noisier than before it failed. I commented on the noise but they said that was normal and departed.

Two days later, my closest neighbor stopped by to (apologetically) complain about the noise. The next day, the neighbor on the other side of me came over to complain that the heat pump was waking her at night.

I need a workable solution. There must be some way to muffle the start up noise. That's what my neighbors are complaining about, not the normal humming/rushing sound.

I think this is your complete model number:
25HBA324A0031010

Guys, the BOM says it has a muffler and an accumulator. Crackcase heater and TXV are an accessories.

Also 13 seer with Puron.

This unit can have up to 250 feet of equivalent line set (elbows and all) but there is a long line set piston resize chart.

How far are the indoor unit and outdoor from each other?

Is the indoor above or below the outdoor unit?

I think someone knew sooo much they didn't bother with reading over that little installation manual.

I didn't look at the wiring diagram but can when/if we get there.

Almost forgot, sound rating for this unit is 74 dBa.

You're right. The confusion is because there are two places where "model" number is shown. The top of the sticker says the model number is 25HBA324A310 but two thirds of the way down, next to the bar code, it says the model number is 25HBA324A0031010. There's a sticker on the side that says PURON. Another sticker says the TXV is factory installed. I wouldn't know a TXV from an RV (rec. veh.) so I can't say if it's really there.

The outside unit is 15 feet from the inside unit in the garage. The inside unit is about 5 feet off the floor of the garage. The outside unit sits on a four inch slab on the ground. Ground level and the floor of the garage are approximately the same.

I live in a standard duplex where the two halves are connected by the garages. Behind the garage is a small room. The outside unit is right outside the small room, directly under the window. In my opinion, that's a poor location. The outside wall at the end of the duplex has no windows. Despite being closer to the bedroom, I think it would have been a better choice. The compressor would be farther from my neighbor in the other half of the duplex though closer to the neighbor on that side. His garage is closest to me so the noise would still be some distance from his bedrooms or living room.

Is there some sort of recommended installation guide that says not to install the outside unit right under a window or a normal business practice standard that says installing outside windows is a no-no?

If I want the unit moved to the far wall (without windows), do I have to eat the full cost or should the installer pay part of the cost?

Since my last update, a tech brought out a padded plastic bag that he placed over the compressor in the outside unit. A couple days later, my neighbor stopped by to ask when she could expect the noise to be reduced. She's still being polite but I don't know how much patience remains. A fix for the noise problem is required. Any suggestions would be appreciated.

You may want to go back and review Mr Fixits advice. Your unit is screaming and is gonna die a agonizing death!!! If this were a pet cat or dog we would see you on the 6:00 news as a jailed abuser, yup you would have one of those ankle bacelets like Martha had. It was run without refrigerant and the compressor is Bad GET YOURSELF A NEW UNMOLESTED UNIT MAN. These people have messed you over, demand a new condensing unit now man. Time to stand up for your rights. Good Luck

I'm starting to wonder if the doom sayers are right about my heat pump. The latest installment in my saga happened sometime last night after I went to bed and before I woke this morning (Dec 26). The outside temperature fell to 34 degrees. The inside temperature dropped to 65 as programmed. This morning, the heat pump came on but the temp didn't rise.

At 6 AM, the temp was 65 degrees. By 8 AM, the temp had only climbed to 66 degrees. Around 10, the outside temp started climbing and by noon, the inside temp was a toasty 67. Brrr. The thermostat was set at 70 the entire time. We called the heating contractor at 9 AM and someone showed up at 1 PM.

He tinkered with the inside unit and replaced two plug-in relays that he said came out of the sequencer. He said it was a warranty repair so there was no charge. The heat is working now but I'm wondering if there's a lemon law for heat pumps. This one is barely 4 months old and it's seems to me that it's having more than its share of problems.

Charlie.

We don't come to these forums to make money from anyone. Most of us have been in HVAC for many years. Personally I started learning it in 85 and finally landed a Navy school in 88. Sometimes I think Ed actually knew Willis Carrier and gave him pointers (just kidding Ed).

We can only take the info you provide and use it to "long distance troubleshoot".

I can only echo Saturn and MrFixIt, the compressor is on it's way to greener pastures.

Might be time to write a letter to the company or even "lawyer up" because your compressor (I think) is going to die soon and there will be no noise at all.

Also seems that you've been going through one thing after another, after another. Compressors make noise and ONLY scream for help. At 74dB it shouldn't bother the people next door.

As far as unit placement goes, Installers install and Techs repair. The Installer wants to get in and out in the least amount of time for the most amount of money.

I have another newbie question about this heat pump. Last night, the temp fell to 31 degrees. The house temp is programmed to allow a fall to 65 at night. The heat pump came on at 3:30 AM and never stopped. Nature called at 5 AM and I checked the temp in the house. It was 64 degrees F. At 7 AM, the temp was still 64. Finally, around 8:30, the electric heat switched on and brought the temp to 68.

That sequence has happened every time the temp falls below about 37 degrees F. Is this normal? Shouldn't the heat pump turn off and switch to backup electric when it gets too cold? Or at least use the backup heat when the inside temp doesn't change after an hour or so. From 3 AM to after 8 AM seems a bit long to wait.