installing a water hammer arrestor

[m4rcone]

I'm looking to install a store-bought water hammer arrestor at the faucet, without soldering. For this, I would require an adapter that goes from the

3/8 inch compression thread that is common on faucet shut-offs (where I would tee off to attach the arrestor) to the 1/2 inch pipe thread that the adapter has. Problem is, such an adapter does not appear to exist, or at least, none of the stores in my area carry one. Anybody ever install a water hammer arrestor this way? How did you do it?

[Speedy Jim]

Get a 3/8" Compression TEE. Insert that in-line. Then, get a 3/8 compression X 1/2" ips (PIPE) adapter.

Use a short stub of 3/8" tube to go from TEE to adapter. Those items should be available at the Big Box or at a decent hardware store.

Jim

[m4rcone]

Putting a tee inline (in the tube going to the faucet) won't work, as it is the kind that is covered with a stainless steel braided sleeve. I did find a tee that inserts between the tube and the shutoff valve (its advertised purpose is to branch two lines off a valve that only has a connection for one), however that then leaves me with the problem that there appear to exist no adapters for going from this 3/8" thread to the 1/2" pipe thread.

[Speedy Jim]

some selections. If you put the TEE after the valve, your braided supply line will (should) fit the TEE.

Adapter from 3/8" tube to 1/2" IPS is a common item.

Jim

[m4rcone]

Yes, that was my plan.

That neither Home Depot nor OSH appear to have in my area (San Jose)

[PJx]

Drop by a plumbing supply and let them work out a solution for you. Don't try to figure it out yourself.

PJ

[m4rcone]

I wasn't imaginative enough, it turns out. While HD and OSH don't have a brass adapter for my purpose, they do sell 12 inch lenghts of tube with those connectors, normally used to hook up a faucet. That, combined with a 3/8 tee, worked just fine. The bad news is that the addition of the water hammer arrestor didn't stop the banging in the water heater when turning off the hot water. I'll try again tonight with a simple air chamber, in case the piston in the arrestor got stuck or something.

[Speedy Jim]

1) Is this a single bang (rather than a rumble) when *any* Hot faucet is closed? 2) City water? High pressure? 3) Gas water heater? Bang only when heater is firing, or anytime?

Any other clues...

Jim

[m4rcone]

I wouldn't quite call it a rumble. It's more like a single bang and then some "echos". Happens only with the kitchen faucet, and only when it is closed quickly.

City water, 60 PSI

It's a gas heater, but I haven't really paid attention to whether it only happens when the heater is firing.

[Speedy Jim]

Does sound like true water hammer. I'm surprised the arrestor didn't help. Seems contrary, but maybe put that one (or another) at the heater.

Jim

[m4rcone]

I replaced the arrestor with a simple air chamber, and that worked. I'm guessing the arrestor was at the store for so long that the piston got stuck.