How long have you had it? Where the shipping bolts, if any , removed from the compressor mounts - common install error which makes a huge difference in operating noise. Unit might need to be on a soundpad if not already.

Sound insulation is tricky. All the insulation in the world won't help with vibration or harmonics. Blower noise may be transmitted through ductwork.

It may sound like a large air conditioner because that's what it be...

Ditto to above with the compressor mounts, which I don't know anyone installing could forget to remove, and the base pad for the unit. But also vibration can be amplified through rigid connections such as power conduit (should be flex); and water piping shouldn't be hard clamped anywhere near it. Mine is clamped over insulation and I have flex hoses making final water connection to units.

However, since you said the noise issue is only during the first 15 seconds and not during continued operation, this doesn't look like your problem and its something more unit related to its startup.

What is the unit setting on?

In my last house the GSHP was in the attic (I know I know). It made a horrific loud noise for a short while when it started up. I found four shock vibration damper pads from a local industrial supply warehouse. The unit (horizontal) sat inside a large metal condensate pan. I installed the pads on a sheet of plywood and placed it under the GSHP. Problem solved. It was a 1' square sheet and cost something like 40-50 bucks. But the silence coming from the attic was well worth it.

My geo system does not make any loud noises.  It sits in my basement on the concrete floor.  The duct that comes out of the top of the unit does have a flexible portion made out of a different material (see photo).  It has been my understanding that geo systems are fairly quiet compared to traditional systems and even though they are a large compressor they should NOT be as loud as an air conditioner.  I am not an expert, just a homeowner, so take that bit of info for what it's worth.  It probably also depends on how old the system is.

What unit do you have? (make and model #)

I have read that they sound like refrigerators. Sounds more like a window AC to me. I can have a normal conversation (well, speaking in a normal voice anyway) right next to both our units running in our basement (even at startup).

If (like us) you ever had an outside AC compressor running in the summer AND (or) an air source heat pump running all year round (and the blasted defrosting in the winter) with the units right outside your 1st floor master bedroom, you will soon be grateful you are now rid of those units! I swear, sometimes I can still hear them run even though they have been removed since April. Man - now I'm hearing things in addition to my Geothermal OCD. Hope long term Geothermal use and these forums will ease the symptoms.

Mine is no louder than the old a/c blower that it replaced. I have to admit, though, that when it was first installed, it DID sound like a jet plane or something...a HUGE woosh of air. The HVAC guy found some DIP switched on the unit and lowered the maximum fan speed. Much quieter now....I don't even hear it come on and off except for the thermostat making a very quiet clicking.

For the compressor shipping supports, open up one side of the unit to get a view of the compressor (just in case - its the tall cylinder).  It should be mounted by four bolts through springs and you should be able to see the springs if not blocked by something else.  Wiggle the compressor back and forth and its should feel like its riding on springs. 

There were U shaped brackets around each spring on mine, which prevents compressor movement during shipping.  The bolts needed loosening slightly and the brackets slid out.  But a couple were hard to get at. 

Now, make sure you see or feel all four bolts and springs.  It could be one of the brackets was not removed, perhaps the hardest to get at.  So you may need to remove another side panel of the unit to confirm. 

I'm not an expert. Since you're not checking for anything electrical, turn off all power at the breaker prior to going inside the unit, right?

I have attached a couple pics of the unit and a link to a video of it starting up. I noticed while filming the noise was not that bad. Maybe when door is closed the room is vibrating and is more apparent outside.

http://www.youtube.com/watch?v=iSAN8S6TpAc

To help find the source of the noise you can use a long screwdriver. With the handle held to your ear, touch the blade to a solid object that might be making the noise. It works sort of like an amplifier or stethoscope. It's not a perfect science but it will guide you close to the source. Mechanics use this trick to identify the area or source of unusual noises in a running engine. Try listening to the sheet metal duct and the metal bands that bind two sections together. It could be a loose connection there.'

Also you mentioned the plastic base which is seen in the photo.  They are typically used for outdoor units on a typical heat pump.  I think a rubbe or dense foam pad would be more appropriate and help isolate or dampen vibration.

John

stevecaz apparently has a Climatemaster, the springs he describes are not true of every brand (don't know about yours).
Is system 1 or 2 stage?
Copeland compressors for some odd reason are louder wired 1 way than another. Ask your installer to try a switch.
I have a FHP product in the field that is louder in stage 2 than 1. That's just a compressor problem.
j

The Hudron owners manual (page 7) says to install the unit on an air pad or vibration damper.  Here is the link to the owners manual.

http://www.hydronmodule.com/Websites/hydronmodule/Files/Content/341099/23230030001_%2803SEPT09%29.pdf

Also it looks like the ducting off the left of the unit and up to the ceiling is metal to metal all the way, unless I'm missing it. Reading through the manual it makes reference to "Remove Packaging Material form the Compressor" but does not mention shipping bolts or clamps. Maybe there are no shipping bolts?

My guess is that the unit is sitting on a hard base on top of concrete, and the metal duct has no flexible isolation joint installed.  All that flat sheet metal would make a perfect diaphragm.

John

Thanks for the info. It does have a flexible connection to main unit but after that all ducts are metal to metal. I will look into the dampening base. But I have a feeling the noise I am bothered by is the startup of the compressor - it is a buzzing electrical sounding noise that only lasts for about 15 seconds and has a clunk to it like a solenoid switch or something.

Ohhhh. Does it sound like a clunk and then buzz similar to the buzzing sound you hear when a security guard presses a button to temporarily unlock a security door? Is your unit a Hydron H Series 2 Stage?

We have installed numerous Hydron Units. None of them make a noise like are describing. Not sure what is up with yours, but it is not normal.

Yes, that is exactly the buzz sound and yes it is a 2 stage H038 unit.

Although I have only have a very minor slight basic conceptual understanding of refrigeration systems, electrical devices are more familiar... I think you have an electrical problem.

I would have the installer check the wiring for the compressor and blower. If you are experienced with high voltage electrical systems you can check. These are high voltages and can cause serious harm or death. Not only can these things shock you so bad that bystanders will see your bones and make your hair look like it is on Viagra, you can inadvertently release the factory installed smoke causing permanent damage to the unit. Please only investigate these things if you are experienced with electrical devices. Otherwise, have the installer check.

Listen closely to the unit when it starts up. Does the clunk/buzz come from the upper half of the unit or lower half? The upper half of your unit has the fan motor. It should turn on very quietly and slowly come up to speed. And then the compressor (in the lower half of the unit) should start up.

There are large capacitors that help the motors turn on and "ramp up" to speed without cutting the voltage so low it causes the lights in your house to dim or flicker. They also increase the efficiency of the motors. If it is a single phase motor (which I "think" it is) it will not start without the capacitor. Another item is the compressor solenoid which also runs on AC. The sound you hear could be from several things gone bad:

- A bad run capacitor or motor internal start-up circuit (blower motor or compressor). The run capacitors are sized according to the motor demands and supply voltages expected from the power company.
-Low voltages supplied to the unit. Do you live far out in the country or experience other anomalies in your house? Such as electronic devices with misbehaving explainably? Or lights seem low or flickering? Do you hear buzzing when the refrigerator or clothes dryer start up? Does the hair dryer have a strange sound or seems to be straining? Those things indicate low voltages in the house.

- A bad compressor solenoid but I don't know if you would actually hear that. It is inside the compressor.

- The black and red wires on the compressor can be reversed. I read this, but don't understand why the compressor motor would be sensitive to that. It could have something to do with the start-up circuitry inside the compressor. Reversing the polarity is an easy fix if in fact that is the cause.

See page 42 (lower right hand corner) on the wiring diagram on the Hydron website. (Link below) It shows a capacitor with yellow wires. One yellow wire connects the capacitor to the compressor and the other yellow wire connects to the compressor contactor. Look more closely to the diagram and you will see the capacitor actually connects across the "R" ans "S" terminals of the compressor. The run capacitor appears to be installed just outside of the controller enclosure in the lower half of your unit.

http://www.hydronmodule.com/Websites/hydronmodule/Files/Content/341099/23230030001_(03SEPT09).pdf

Please do not electrocute yourself.

John