I installed 4 grohe thermostatic valves today with volume control valves. 3 showers and one tub. I ran water to them and found that two of them would hammer when turning off the volume valve. Because I used pex I can see that there is air in the lines. I have let them run for about 20 minutes but the air doesn't want to come out. I can't see it when the water is flowing, but when I turn the water off I get the hammer noise and then the air appears and it looks like it comes out of the valve into the pex.

Will this air come out of the water line with use? Or is there something I should do? I would like to make sure that my pipes won't be hammering once I have my drywall installed.

Thx

On Mar 18, 8:36*pm, "Gary" wrote:
I installed 4 grohe thermostatic valves today with volume control valves. 3 showers and one tub. I ran water to them and found that two of them would hammer when turning off the volume valve. Because I used pex I can see that there is air in the lines. I have let them run for about 20 minutes but the air doesn't want to come out. I can't see it when the water is flowing, but when I turn the water off I get the hammer noise and then the air appears and it looks like it comes out of the valve into the pex.

Will this air come out of the water line with use? Or is there something I should do? I would like to make sure that my pipes won't be hammering once I have my drywall installed.

Thx

The air should clear on its own...if you;re getting hammer, pressure
is too high, valve shutoff too quick, need to add arrestors

cheers
Bob

"fftt" wrote in message
...
On Mar 18, 8:36 pm, "Gary" wrote:
I installed 4 grohe thermostatic valves today with volume control valves.
3 showers and one tub. I ran water to them and found that two of them
would hammer when turning off the volume valve. Because I used pex I can
see that there is air in the lines. I have let them run for about 20
minutes but the air doesn't want to come out. I can't see it when the
water is flowing, but when I turn the water off I get the hammer noise and
then the air appears and it looks like it comes out of the valve into the
pex.

Will this air come out of the water line with use? Or is there something I
should do? I would like to make sure that my pipes won't be hammering once
I have my drywall installed.

Thx

The air should clear on its own...if you;re getting hammer, pressure
is too high, valve shutoff too quick, need to add arrestors

cheers
Bob

Thanks Bob. I just put a pressure gauge on it and got 85psi. Should I be
looking for a regulator?

On Wed, 18 Mar 2009 21:36:05 -0600, "Gary"
wrote:

I installed 4 grohe thermostatic valves today with volume control valves. 3 showers and one tub. I ran water to them and found that two of them would hammer when turning off the volume valve. Because I used pex I can see that there is air in the lines. I have let them run for about 20 minutes but the air doesn't want to come out. I can't see it when the water is flowing, but when I turn the water off I get the hammer noise and then the air appears and it looks like it comes out of the valve into the pex.

Will this air come out of the water line with use? Or is there something I should do? I would like to make sure that my pipes won't be hammering once I have my drywall installed.

Thx

The air in the lines will likely disappear in time. In any
case that air would reduce water hammer not cause it. You may need to
add anti-hammer devices at the end of the runs. If it is a worry, all
you can do is to add the devices, or be ready to open the walls later.

Gary wrote:
"fftt" wrote in message
...
On Mar 18, 8:36 pm, "Gary" wrote:
I installed 4 grohe thermostatic valves today with volume control valves.
3 showers and one tub. I ran water to them and found that two of them
would hammer when turning off the volume valve. Because I used pex I can
see that there is air in the lines. I have let them run for about 20
minutes but the air doesn't want to come out. I can't see it when the
water is flowing, but when I turn the water off I get the hammer noise and
then the air appears and it looks like it comes out of the valve into the
pex.

Will this air come out of the water line with use? Or is there something I
should do? I would like to make sure that my pipes won't be hammering once
I have my drywall installed.

Thx

The air should clear on its own...if you;re getting hammer, pressure
is too high, valve shutoff too quick, need to add arrestors

cheers
Bob

Thanks Bob. I just put a pressure gauge on it and got 85psi. Should I be
looking for a regulator?



All the Watts water pressure regulators I've ever
installed came from the factory preset to 50 psi.
If your static water pressure is 85 psi and there
is no regulator (municipal water), there could be
spikes in pressure that can blow toilet valves and
sink washers, etc. I once replaced a defective
water pressure regulator at a service station that
had 190 psi static pressure. The spikes is water
pressure were much higher than that. All of the big
chrome Sloan flush valves in the rest rooms were
damaged by the high pressure. The sink washers in
the kitchen were blowing out. After replacing the
1" regulator everything was fine. The hose spigot
outside still had 190 psi and it would project a
stream of water quite a distance. If you don't have
a regulator, you should install one or repair what
you have.

TDD

Gary wrote:
"fftt" wrote in message
...
On Mar 18, 8:36 pm, "Gary" wrote:
I installed 4 grohe thermostatic valves today with volume control valves.
3 showers and one tub. I ran water to them and found that two of them
would hammer when turning off the volume valve. Because I used pex I can
see that there is air in the lines. I have let them run for about 20
minutes but the air doesn't want to come out. I can't see it when the
water is flowing, but when I turn the water off I get the hammer noise and
then the air appears and it looks like it comes out of the valve into the
pex.

Will this air come out of the water line with use? Or is there something I
should do? I would like to make sure that my pipes won't be hammering once
I have my drywall installed.

Thx

The air should clear on its own...if you;re getting hammer, pressure
is too high, valve shutoff too quick, need to add arrestors

cheers
Bob

Thanks Bob. I just put a pressure gauge on it and got 85psi. Should I be
looking for a regulator?


Not Bob but 50 PSI is plenty for a properly piped system.

On Mar 19, 2:23*am, "Gary" wrote:
"fftt" wrote in message

...
On Mar 18, 8:36 pm, "Gary" wrote:

I installed 4 grohe thermostatic valves today with volume control valves.
3 showers and one tub. I ran water to them and found that two of them
would hammer when turning off the volume valve. Because I used pex I can
see that there is air in the lines. I have let them run for about 20
minutes but the air doesn't want to come out. I can't see it when the
water is flowing, but when I turn the water off I get the hammer noise and
then the air appears and it looks like it comes out of the valve into the
pex.

Will this air come out of the water line with use? Or is there something I
should do? I would like to make sure that my pipes won't be hammering once
I have my drywall installed.

Thx

The air should clear on its own...if you;re getting hammer, pressure
is too high, valve shutoff too quick, need to add arrestors

cheers
Bob

Thanks Bob. *I just put a pressure gauge on it and got 85psi. *Should I be
looking for a regulator?

Gary-


For residential supply, 85 psi is rather high. The arrestor folks
(jrsmith mfg) suggest keeping pressure under 65 psi.

When I repiped I installed arrestors in various locations and a Watts
pressure reducing regulator. I went from 75 psi down to 65 psi. I
miss the "firehose" behavior of my garden hoses but I don't have any
hammer.

If oyu really want to read about arrestor behavior & placement

http://www.jrsmith.com/products/water/pm/pm1054.pdf

I cheaped out & didnt put on on my upstairs toilet....still had
hammer, but attic access allowed me to install one in a few minutes.

Even with PEX (which is more flexible than copper or steel) I would
put arrestors in kitchen (d/w & ice maker), laundry for sure and all
toilets. My downstairs toilet only has about a 15' run from the
manifold...no arrestor / no hammer.

cheers
Bob

my psi is 85, I am going to put a pressure reducer on the house.


wrote in message
...
On Wed, 18 Mar 2009 21:36:05 -0600, "Gary"
wrote:

I installed 4 grohe thermostatic valves today with volume control valves.
3 showers and one tub. I ran water to them and found that two of them
would hammer when turning off the volume valve. Because I used pex I can
see that there is air in the lines. I have let them run for about 20
minutes but the air doesn't want to come out. I can't see it when the
water is flowing, but when I turn the water off I get the hammer noise and
then the air appears and it looks like it comes out of the valve into the
pex.

Will this air come out of the water line with use? Or is there something I
should do? I would like to make sure that my pipes won't be hammering once
I have my drywall installed.

Thx

The air in the lines will likely disappear in time. In any
case that air would reduce water hammer not cause it. You may need to
add anti-hammer devices at the end of the runs. If it is a worry, all
you can do is to add the devices, or be ready to open the walls later.

On Thu, 19 Mar 2009 18:39:53 -0600, "Gary"
wrote:

my psi is 85, I am going to put a pressure reducer on the house.



Well with 85 psi I would not be at all surprised that you had
water hammer. Reducing it likely will eliminate the problem.

On Mar 19, 5:23*am, "Gary" wrote:
"fftt" wrote in message

...
On Mar 18, 8:36 pm, "Gary" wrote:

I installed 4 grohe thermostatic valves today with volume control valves.
3 showers and one tub. I ran water to them and found that two of them
would hammer when turning off the volume valve. Because I used pex I can
see that there is air in the lines. I have let them run for about 20
minutes but the air doesn't want to come out. I can't see it when the
water is flowing, but when I turn the water off I get the hammer noise and
then the air appears and it looks like it comes out of the valve into the
pex.

Will this air come out of the water line with use? Or is there something I
should do? I would like to make sure that my pipes won't be hammering once
I have my drywall installed.

Thx

The air should clear on its own...if you;re getting hammer, pressure
is too high, valve shutoff too quick, need to add arrestors

cheers
Bob

Thanks Bob. *I just put a pressure gauge on it and got 85psi. *Should I be
looking for a regulator?

I have a multi-family building (4, 8-plexes) and the sprinkler gauge
holds a steady 85 psi. We don't have any pressure reducers. No
plumbing problems and no hammering (expect 1 building did hammer for
the first month).