In mid-summer I had the blower motor and capacitor replaced in my Comfortmaker RPG II 150,000 BTU natural gas furnace. (The bearing was going out in the motor). This is a direct-drive squirrel cage blower.

Since being replaced, it makes a loud 60hz hum startup noise. It varies in pitch as the motor groans to spin up the blower (wa... wa... wa.. wa,wa,wa,wa). After a few seconds the noise disappears and the blower continues to spin up until operating at full speed. Other than the startup, the blower sounds the same as it did before the motor was replaced.

I didn't think anything of it since I trust the HVAC contractor (15 year relationship) and I was standing right behind him when he started the blower for the first time after he finished replacing the motor.

A month ago I had the same firm come out and perform a "fall inspection". At the end of the inspection the guy said that the motor didn't sound good and was probably going bad. He recommended that we replace it. My wife told him that we just had it replaced a few months prior. He said he would get back to us on warranty and that they would probably replace the motor at no charge.

After a couple weeks and no call back, my wife called. A couple more weeks and no call back. I called and the owner immediately called back and said that we had a "big" 1HP motor and that they make a noise when they startup. I told him that the previous blower did not make any noise when starting. He said that we were a long time customer and that he wanted to make us happy. He is coming out to inspect the blower motor.

At this point I'm not sure I know what to think about the situation. I thought I trusted this contractor but the sound the furnace is making is the same sound that it made immediately after the blower motor was replaced. As I said before, I was standing right behind the contractor when he started the furnace. He didn't mention anything about the noise then.

My question: Is this normal? Do "big" 1HP motors make a "groaning" sound when they start? Based on my previous experience I would say no but I don't want to sell this guy short or confront and ruin an otherwise good long-term relationship.

In mid-summer I had the blower motor and capacitor replaced in my Comfortmaker RPG II 150,000 BTU natural gas furnace. (The bearing was going out in the motor). This is a direct-drive squirrel cage blower.

Since being replaced, it makes a loud 60hz hum startup noise. It varies in pitch as the motor groans to spin up the blower (wa.....wa...wa..wa,wa,wa,wa). After a few seconds the noise disappears and the blower continues to spin up until operating at full speed. Other than the startup, the blower sounds the same as it did before the motor was replaced.

I didn't think anything of it since I trust the HVAC contractor (15 year relationship) and I was standing right behind him when he started the blower for the first time after he finished replacing the motor.

A month ago I had the same firm come out and perform a "fall inspection". At the end of the inspection the guy said that the motor didn't sound good and was probably going bad. He recommended that we replace it. My wife told him that we just had it replaced a few months prior. He said he would get back to us on warranty and that they would probably replace the motor at no charge.

After a couple weeks and no call back, my wife called. A couple more weeks and no call back. I called and the owner immediately called back and said that we had a "big" 1HP motor and that they make a noise when they startup. I told him that the previous blower did not make any noise when starting. He said that we were a long time customer and that he wanted to make us happy. He is coming out to inspect the blower motor.

At this point I'm not sure I know what to think about the situation. I thought I trusted this contractor but the sound the furnace is making is the same sound that it made immediately after the blower motor was replaced. As I said before, I was standing right behind the contractor when he started the furnace. He didn't mention anything about the noise then.

My question: Is this normal? Do "big" 1HP motors make a "groaning" sound when they start? Based on my previous experience I would say no but I don't want to sell this guy short or confront and ruin an otherwise good long-term relationship.
My guess would be since this is a new motor, there is a problem with the run capacitor, bad or wrong size, making the motor struggle to start. Either way, this should be under a part and labor warranty, threaten him with a call to the BBB, if this is not soon corrected to your satisfaction. I might also tell the owner how sad it would be to end a 15 year relationship over such a simple remedy.

Was it the owner himself that was there when the motor started up? If not, give him a chance to hear it himself and make it right. Let the harsh words be between him and his help. Otherwise, www.bbb.com.

My guess would be since this is a new motor, there is a problem with the run capacitor, bad or wrong size, making the motor struggle to start. Either way, this should be under a part and labor warranty, threaten him with a call to the BBB, if this is not soon corrected to your satisfaction. I might also tell the owner how sad it would be to end a 15 year relationship over such a simple remedy.

Thank you very much for the response.

Regarding the "new motor"... how do I know the motor is new? After removing the previous motor, he took it to the truck and returned with a "different" motor but at this point, I'm questioning whether it was new or a motor removed from the last guy's furnace because it was noisy. Right now I'm questioning everything since I kind of caught the contractor in what I consider a "pickle" (his own employee not knowing that the motor was just replaced thinks it's bad... ) I do know that the bill included a new capacitor and a visual inspection of the work he performed seems to confirm that there is a new capacitor on the motor (bright, shiny and freshly wired). Could it be undersized or could it have just been bad from the start? If it was bad and it's been "struggling" for several months, will this affect the life of the motor?

Another issue that contributes to my suspicion is the fact that during the repair, he broke the "safety" power cut-off switch. I did not know this but he told me he broke it and that he had temporarily bypassed it. He returned a few days later and installed a new switch. That evening I inspected the switch repair and discovered that the switch was still bypassed. I removed the bypass and the furnace would not work. Further diagnosis revealed that the switch does not protrude far enough to be depressed when the door is reinstalled. (It's just not the right switch.) Thinking that this was an honest oversight, I reinstalled the bypass and let it go. However, now this makes me wonder even more...

The problem I have is that this guy has been awesome over the years. Ten years ago he came through for us on very cold Saturday night. I called him and told him that the furnace's trouble code was flashing "draft inducer" problem. He didn't have the part, asked that I try other contractors. An hour later he called me back to make sure I had heat. When I told him I still had not found anyone with the part, he sprung into action, found someone willing to open their warehouse and kept us warm.

I really hate to question the guy but between the motor and the switch, I'm very disappointed with this repair and his reaction to the problem. It would be different if it starting making this noise a few days, weeks or months later but it's been making this noise since day 1, he heard it the first time he started the blower and he chose to do nothing about it. That just bugs the hell out of me. It makes me feel like a sucker because before his employee cited the motor problem, I implicitly trusted him.

Was it the owner himself that was there when the motor started up? If not, give him a chance to hear it himself and make it right. Let the harsh words be between him and his help. Otherwise, www.bbb.com.

Unfortunately it was the owner that did the repair, not his help. As I stated in my original problem statement, it was one of his employees that did the routine inspection and questioned the health of the motor some months after he installed the new motor.

I don't think he has a "big" business. Although I don't know exact numers, I think it's just him, his wife (handling the office) and maybe several employees who work jobs with him. As such, I would prefer not to get the bbb involved.

Large motors with a capacitor should start with a "Bang" and now the wa wa wa that you described. Others above have given you good answers to your questions, I just want to add one thing. A person can make a mistake and bypass the capacitor by wiring it wrong. It that did happen it would have made that noise from the very first start. Then also it could be a bad capacitor at the time of installation.

Large motors with a capacitor should start with a "Bang" and now the wa wa wa that you described. Others above have given you good answers to your questions, I just want to add one thing. A person can make a mistake and bypass the capacitor by wiring it wrong. It that did happen it would have made that noise from the very first start. Then also it could be a bad capacitor at the time of installation.

Thanks for the insight. Is it possible to perform a visual inspection to determine if the capacitor was wired wrong or does it require specific measuring devices and "know how" to make this determination? If it's wired right, is there a simple test for the capacitor?

Also, will a bad capacitor or improperly wired capacity adversely affect the life of the new motor?

Unless I can perform a simple visual inspection, I am going to find another contractor to come out for a second opinion and if he can fix the problem, I will file a BBB suit. The problem now is that I have a year contract with the current guy so I guess I'll have to eat that too. I don't want anything more to do with this company.

I want to thank everyone for their comments. They have been very valuable and I'll be making contributions to each of you in the near future after I get this worked out.

Might post checking the capacitor leads to E&L and see what tkrussel has to say. I say specific leads need to be connected to the capacitor, and they can only be determined from the manufacturer's color code. You might see if it is on the motor nameplate. If it isn't, write the brand and model down and take it to a dealer. They may dig it up for you.

I installed a new motor last year and new out of the box it made the same noise you are talking about. Motors are being made cheaper with less iron 9Magnet surface0 and less copper on the armature. Seems to be a standard problem today. I ordered a Baldor motor that is twice the weight of the noisy motor and installed it. Noise is now gone but wholesale on the motor was 138.00. The standard replacement 1/2 HP motor cost 37.00 BIG price difference and big performance difference also.