Goodman evap coil noise

[bryan's world]

I just installeld a Goodman 1.5 ton split... pressures are fine but the evap coil is making a heck of a racket. It is definitely refrigerant noise, because it doesn't happen with just the furnace fan running. Its an uncased A coil, and I didn't mess with the metering piston because it's a matched system. I'm waiting to hear from Goodman, so if anyone has had this experience please give me your comments. This is a new one for me.

[casturbo]

Improperly charged or the refrigerant is contaminated with air and whatnot.

[bryan's world]

I thought that might be the case too, but I pulled a deep vacuum for a couple of hours on the lines & coil before letting the charge go, like I always do, and never had this problem before. Also the pressures would be off & icing would occur if the charge needed adjustment. It's pulling gallons of condensate, so I can't see the charge being the problem.

I'm suspecting the metering piston is chattering or something like that. Its a loud "buzzing" noise, like a kazoo, is the best way to describe it. I'm really puzzled.

[RoBoTeq]

Just because it is a rated system does not mean that it is a matched system. What indoor coil did you use?

Most indoor coils for 1.5 ton systems require a piston change. I believe the piston required is a .052

If the piston is oversized there is no way to achieve the proper superheat without winding up with too high of a suction pressure.

[bryan's world]

Thanks for your comments. I really do appreciate another mind on this one. I'm really getting frustrated, and I don't just want to blow the charge for nothing.

The coil and the unit are 18,000 btu. The coil model is CAUF018A2A I believe the coil lit. says it ships with a .52, and there is no need to change it if you use a 1.5 ton condensing unit, which I did. Of course I didn't think to check it when I was rushing to put it together... but I really don't think the wrong size could cause a noise like this, could it???

I used no more than about 20 feet of line, 3/4 and 3/8, right to spec as far as I know. All components are Goodman. (including the furnace, which was installed last fall)

Any other suggestions??? I still haven't heard anything from Goodman.

[bryan's world]

I just spoke with a Goodman rep who said the factory could have put the piston in backwards, or else it's not seating right... he said he's heard of this before, causing noise. Just you everyone's info. I'll pump it down and open it up again. Let y'all know what I find.

[RoBoTeq]

OK, so if the coil has the proper piston and is charged properly, lets look at other factors.

Is this a gurgling, hissing or rattle type of noise?

Sometimes a liquid line that has a lot of straight line running directly straight to the coil can lift the piston causing a rattle type of noise. If this is the issue, offset the liquid line a bit close to the coil connection.

That model coil requires the liquid line stub be brazed to the lineset, then after cooling attached to the piston housing. Is it possible the piston neoprene seal or the neoprene seal for the piston housing halves could have been overheated? Could the piston have been accidentally put in backwords? This could be causing too much refrigerant to pass by the piston causing a gurgling sound.

Has the airflow been reduced to the lowest setting for the low capacity cooling system? Is this a furnace or an air handler? Which model?

[tcat007]

Sorry to butt in here, but you may have hit my nail on the head. I've had a gurgling sound ever since carrier put my unit in (1.5 years). I had believed they overheated the connection at the Evap coil, and possibly damaged the TXV. I've had them out twice to listen to it, and they say it's "normal".

I've never heard it in anyone elses house... only happens when cooling season starts, gurgles for about 3 minutes and stops. If you touch the liquid line you can feel it vibrating from the gurgle. Doesn't really bother me except at 2:00AM when it seem twice as loud, and seems to last twice as long.... not sure what to do since the contractor and the Carrier rep have both been out.

[RoBoTeq]

Then again, some systems just have quirky sounds when they are operating perfectly. There is usually something that "can" be done to tone down odd sounds, but first you have to identify the sound, where exactly it is coming from and what is most likely causing the sound.

Sometimes compressor sounds transmit through the copper lines and eminate from the indoor coil.

[bryan's world]

Thanks for your comments, RoBo... It sounds like a VERY LOUD Kazoo (wax paper on a comb, if you can't afford a kazoo!!) A mid-pitched buzzing noise is all I can think of description-wise, so loud the HO has to turn up the t.v. when the unit is running! It's definitely NOT gurgling refrigerant. There's a hand-bent 90 degree in the line about 6 inches from the coil, so nothing straight about it. But that's a good thought.

So now that I think about it, because of the configuration, I didn't have room for the back-up wrench on the fitting once the coil was placed, so I braised it connected. I used a wet rag as a heat sink on the fitting, and silver solder to keep the temp to minimum, but I guess I could have pooched the seal on the piston. I suppose I should get a replacement piston before I open it up. The fitting isn't leaking, so I have trouble believing it got that hot, but maybe the piston seal is more fragile or something.