water shuts off as i open valve

Hello, I need help determining why the bathtub faucet turns off as i open both the hot and cold water valves past a certain point.It was making a banging sound so i placed arrestors on both hot and cold water pipes just before the faucet.The banging stopped but now water will not flow increasingly heavier as i open the valves.Does not occur anywhere else in the house.Thanks.

A picture would help to identify the valve, but it sounds like it may be that the valve you have uses a washer at the end of the stem. If these are worn or loose, they can move around, affect the flow, and in some cases flutter enough to cause the water to turn on/off rapidly making that hammering sound. If that's it, depending on the design, you either have to replace the stems, or just replace the washers. Sometimes, the valve seat needs to be replaced as well. With the right tool, this is a quick and easy job, too.

whatever is causing the loss of pressure, possibly a loose washer, may be what caused the hammering sound and the arrestors were not needed.

You're probably right.The house had been repiped only three years ago and the lady of the house said that this had just started.She also said the hot water pipe(cpvc) coming from the water heater would shake as well before i put the arrestors in place.Where would you start troubleshooting this problem?Electric water heater(3 yrs old also) on a repipe via the addict.
The home is probably 50 years old.Thanks for your input.

If the only place that creates the problem is the tub/shower, then start there.

Thank You, I'll try that tomorrow and let you know how it works out.

As hj mentioned, it could be the fifty year old washers flopping around in the tub faucet as the water flows past.
Normally with a complete repipe, the tub faucet would be replaced with a "to code" single handle pressure balanced faucet.

Same thing was happening to me in Vancouver BC in the Fairmont Hotel.