Do I need water hammer arrestors?

I am installing a Kohler thermostatic valve, and I just noticed that it calls fro water hammer arrestors for the hot and cold water.

It's a 1/2 valve and I was curious if it's necessary?

Thanks,

George

If the manufacturer requires it in their installation instructions, (and the inspector actually reads them, which might be rare), I think it would fail the inspection without them...most things say install per the manufacturer's instructions. Put them in, and don't worry about it...much easier now than later, if you find out they really are necessary. Most valves don't even mention them. But, a high flow rate valve might depending on the design. More typical of a 3/4" valve than probably a 1/2" version (3/4" can flow almost 3x the volume at the same pressure).

They may help but its not the valve that causes the problem, it is the volume controls that are the issue, just learn to shut them off slowly.

arrestors

How many inspectors read the installation instructions so they would know to fail the installation without them. Their duty is to enforce the code requirements, not the manufacturers, so unless their code called for them, (Chicago did require air chambers back in the 50's and 60's), it will pass without them. Now whether you actually need them or not is something you will not know until you start using the valve.

Thanks for the advice guys. It was simple enough to add them, so I figured it couldn't hurt if I did.

Thanks again.

hj said:

How many inspectors read the installation instructions so they would know to fail the installation without them. Their duty is to enforce the code requirements, not the manufacturers, so unless their code called for them, (Chicago did require air chambers back in the 50's and 60's), it will pass without them. Now whether you actually need them or not is something you will not know until you start using the valve.

Click to expand...

Chicago and Illinois state code still does.