Geothermal Solenoid Valve

[Kidd6488]

We have installed (helped install) geothermal heat/cooling in our house, and are concerned about the noise. We can try wrappnig the compressor and stuff, but another large source of noise is the external solenoid valve. Its 24V and 1". Do they usually make a pretty loud hissing noise, or do we have a lemon? If it is common, what can we do to shut it up?

Thanks,

~Jonathon Reinhart

[HayZee518]

I believe what you are referring to is the reversing valve. The hissing noise is normal as the flow of refrigerant is reversed through the evaporator and condenser. In one direction it's used as an air conditioner transferring heat out of the condenser and the other absorbing heat from the ground and passing this through the evaporator as a heater.

[LazyPup]

Wrapping the compressor is not a good idea as the wrapping would also serve as an insulator trapping heat in the compressor housing. The increase in temperature could lead to a premature failure of the compressor.

Possibly a better solution would be to install egg shell acoustic insulation on the inside of the utility room.

[Troy]

I'd love to hear more about your geothermal project. Do you like it? What did you use? How does it work? Would you post some information of what you did here or in the projects section?

Interesting! Thanks!

Try

[Kidd6488]

Hayzee, No, I'm referring to the valve on the OUT side of the furnace that stops the water running through it when the furnace is not running. It makes this pretty loud hissnig noise that occasionally stops for ~10 sec, and it has nothing to do with the well system's pressure (i've checked)...

~Jonathon Reinhart

[imeduc]

You say water valve here and it is off when the furnace is off. Out of the box here but I think its dirt in it lets water run through it and make the noise. when the furnace is on the coil would open it. With well water here you can find anthing in it. Id take it apart and check it. The little rod in it can get lime or calcium on it . Just takes a little bit.

TROY go check out www.amgeo.com

ED



My mistakes dont define me they inform me.

[LazyPup]

KIDD6488
I have attached a cross-sectional diagram of an electro-magnetic solenoid valve.

In the upper drawing you will note that the valve body has a tubular riser to contain the spring and copper-clad steel plunger needle valve.

The Elecctro-magnetic coil is then made in a circular fashion with a hollow center that fits down around the riser.

When the power to the coil is off the spring pushes the plunger down to seat the valve. (The water pressure on top of the plunger also aids in holding the valve closed)

When the coil is energized the coil becomes magnetic and pulls the steel plunger up into the riser, opening the valve, and allowing water flow.

There are two distinctly different noises associated with these type of valve. A low humming or buzzing noise is often caused by internal vibration in the steel plates used to make the core of the electrical coil. That is called "Hysterisys" and aside from being a bit annoying it really doesnt represent any problems. (we often hear the same type of noise eminating from transforemers). Quite often when there is Hysterisys the coil will feel warmer than usual.

The second type of noise associated with these valve is a rapid loud chattering sound which may also be associated with water hammer on the piping system. That is indicating that scale or debris is caught in the riser and not allowing the plunger to pull fully up to the open position. Some valves can be disassembled and the plunger and spring can be removed for cleaning. If not, the solution is to replace the valve.

This same method is used for the electically operated valves on Dishwashers, laundry washing machines and refrigerator ice makers.

The plumbing code specifies that a "water Hammer Arrestor" is to be installed in the close proximity of all fast acting valves such as these.

If your geothermal is using a well source for geothermal energy rather than a closed loop, i would suggest you have a sediment screen installed on the intake side of the valve to help prevent debris from getting into the valve.

[Troy]

quote:Originally posted by imeduc
TROY go check out www.amgeo.com

ED

Thanks for the link, imeduc []

Try

[HayZee518]

sometimes the internal guts of the valve get hung up on "stuff" inside the valve so it starts to buzz. rapping it with a hammer sometimes can stop the humming and buzzing. Seems the quality doesn't go in before the name goes on!

[Kidd6488]

Well this valve was making noise from the first time we turned the system on, so that makes me question whether it could be dirt causing the hissing noise.

But its funny you mention water hammer, and arrestors because that was my next question. When the unit stops cycling, and the solenoid valve shuts off, there is now a pretty violent-sounding "thud" you can call it, that can be heard just about everywhere.

It may benefit you to know briefly how this is laid out. There is just a hose bib and a valve on the "IN" side of the furnace. On the "OUT" side, there is a 6 GPM regulator (or whatever it's called), and then it 90°s down, then to the solenoid valve. From there, it's Cu pipe to the drain.

Where would the water hammer, that I assume is causing the loud "thud", be comming from? I thought I heard that they occur on Tees and Elbows, So you should like put a tee in instead of the elbow, and put the watter hammer arrestor on that new connection...

Thanks,

~Jonathon Reinhart

[LazyPup]

If i am visually picturing this correctly, it is taking water from the well, passing it through the heat exchanger to extract the heat energy and the discharge side of the heat exchanger is being discharged into the drainage system. While that is certainly not the most efficient method, it is the method that was commonly used on Refrigeration water condensers for years.

In your description you state that the line 90's down to the solenoid valve and continues on to the drain. Is the solenoid valve on a vertical line with the solenoid on a horzontal plane with the valve body? If so, the plunger would be moving in a horizontal rather than vertical plane. While they will work in the horizontal plane, graivity is now acting upon the full length of the plunger rather than its diameter, which often retards the action and could result in sluggish motion and well as premature weakening of the spring.

Water hammer is a caused by a rapid change in internal line pressure when a valve is closed. Bernouli's principal states that when there is an increase in velocity, there is a proportionate decrease in pressure , thus when a valve is open and there is a flow of water (increase in velocity) there is a proportionate decrease in internal line pressure. When the valve is closed the velocity stops and the internal pressure immediately rises to equal the source pressure. The rapid increase in pressure, and to a minor degree the inertia of the fluid in motion stopping abruptly causes a physical shock in the pipe which normally causes one and sometimes two loud bangs in the piping system. In a worst case sceanario you can actually see the motion of the pipe shaking when the water hammer occurs.

All plumbing systems are required to have water hammer arrestors, and in situations where the line pressure is anticipated to exceed 85psi we are required to install expansion tanks.

In addition to the normal water hammer arrestors, the codes have now been changed to say that there should be additional water hammer arrestors in the close proximity of all fast acting valves. (Solenoid valves are classified as fast acting valves).

While there are commercially available water hammer arrestors in the $5 to $10 range, one can also be very easily field constructed by installing a Tee and making a vertical riser about 12" to 18" and placing a cap on the top. Whe they system is filled the vertical riser traps air which is compressible and will absorb the shock of the rapid pressure increase, and when the valve is opened the air will expand maintaining a constant equilibrium with the line pressure.

[Kidd6488]

Here is a pretty good representation of how it is set up:



What do you say about the water hammer arrestor placement?

~Jonathon Reinhart

[Dean]

May I ask a dumb question?

What is the purpose of water coming in from a hose bib, going through a PRV & solenoid valve then dumping to the drain?
Shouldn't it somehow be connected to the heating/cooling unit?

I guess I'm confused because we don't have many heat pumps around my area since natural gas is cheaper to heat with.

Just curious.

[Kidd6488]

Not a dumb question, I guess I didn't explain it very well. The water comes in through 3/4" Cu from our well system. There is first a valve and then it goes into the furnace. The hose bib is just tee'd in there for cleaning. I guess you can hook up a pump the circulates a cleaning solution. There's also a hose bib on the OUT side of the furnace.

~Jonathon Reinhart

[LazyPup]

Water hammer arresters are commonly installed in that manner so that would not be a problem, although i do think you would minimize the valve chattering and water hammer problem if the valve were placed on the horizontal line rather than the veritical line.

DEAN. while air exchange heat pumps drastically loose efficiency when the outdoor temps fall below 35 or 40 deg, a geothermal heat pump will maintain full efficiency even when outdoor temps are sub-zero. In that respect, although geothermal is considered very costly to initially install, in the end, it will work out to be the cheapest reliable heating and cooling method.

I am currently designing a small two bedroom retirement home for myself and I am specking it out with geothermal source with a primary radiant floor system, with a water coil forced air backup for quick recovery or peak demand. The house calls for a 3 ton system but i am setting it up with dual compressors, a one ton and a two ton. It will then be able to stage one, two or three ton as needed.