HVAC folks - is this noise normal?

[The Stigenator]

We have roof mounted Lennox heating/ac system. Its one of those compact units that does both. We have gas heating.

Anyway lately this is what I hear when the system kicks in.

15-20 seconds of a loud whirring sound (compressor??) and then 10 seconds of the burners kicking in (growl) and then the fan kicks on.

But I am wondering of the first loud whirring sound. It was never that loud. I dont know what it might be, its on the roof so its not that easy to check out.

The system is blowing hot air, and no problems. I think it does the same for cold air too (but I'll double check tomorrow and have the AC kick in during the day).

I am trying to find the bill. Its about umm.. 5-6 years old.


Edit:

Just updating the specs. I have a Lennox Package system 12GCS036X-75 The install in 2005 cost %3350

 

[iGas]

Could it be resistant compressor/motor noise?

Check/clean/wash debris/snow/ice off the unit it is not clean (also check/replace/clean filter.)

 

[The Stigenator]

THe air filter is on the inside of the house, so I have replaced that, its not that one.

THe rest I have to go up to the roof. I'll try do that tomorrow. There is no snow, ice on it. Its so.cal, but debris might be. The thing is that its not the blower motor, since it comes on before even the burner for the heater comes on.

Its the first thing that turns on when the thermostat kicks in.

 

[Hippiewan]

Gas heating, that would most likely be the inducer motor that kicks in first before the gas fires or the blower motor kicks in. It's the blower that pushes the exhaust out of the unit. Could be that the motor is starting to go bad. They tend to get louder before they die. I would have someone out to check the amps that the motor is drawing to make sure it is not on its way out. If that is not it, could just be something loose on the motor.
Best to have it checked out now, if it dies, you are without heat.

Best of luck.

Been in the HVAC business for about 10 years.

 

[The Stigenator]

Thanks Hippiewan, I'll check it tomorrow (its not going to rain) and then try get an HVAC guy up here.. ugh this is going to be expensive.. anybody know how much a service call is and how much it would cost to fix.

 

[The Stigenator]

Seems like the part is < $100, the labor for it (checking online prices is around 300+). Ugh!

I have to go up to the roof, I hate going up there.

 

[The Stigenator]

Just updating the specs. I have a Lennox Package system 12GCS036X-75 The install in 2005 cost &#37;3350