Water trickles out of hand help head

Clean hand held the unit is probably clogged . If you have ard water you can soak it vinegar for a couple of hours.

That orifice is a flow limiter (to control flow to less than 3gpm). It can be removed.

Hello Mark
is the water still coming out the bottom when you pull up the lever to make the shower come on ? if it is then the tub valve is bad . if little or no water come out of the bottom then the head is going to be clogged and you have have buildup inside the filter /screen which could be located in the end of the hose at the head or inside the head unit itself. .

Take the gasket to your local hardware store and have them match it up.The answer is no, the gasket is not supposed to be split. It was probably tightened too much.

I know the feeling.........I have the same one and made a rubber sleve for the handle........I too should have returned mine..........Hope this helps.

Point your water line into a bucket and turn the water on at the wall. If you get a good flow, we'll go back to the faucet. No kinks in the supply lines, right? The reason I ask is this was reminiscent of a recent problem where my friend could get hot water to the faucet, and it would slowly go down to a trickle. The problem was that the supply hose had a bit of a kink in it, and got choked off when the line got hot.
OK, good flow into the bucket. Sometimes the supply lines can delaminate, and choke the water off as well. Since you have a sprayer faucet combo, make sure that the flex hose that dispenses the water, and has the weight on it to retract the nozzle back up doesn't have a kink either. Remove the spray nozzle, and try the faucet, holding onto the hose. It's possible that the spray selector could have a problem, so check the spray head and diffuser. With the water on, push the sprayer button, and see if the problem might be there. Remove the aerator on the end of the sprayer, and check the screens for pluggage. My guess is that the issue is in the spray head.
Best regards, --W/D--

Soak in vinegar and see if this helps.

you have to take the handle off
there should be an insert that you can adjust by pulling out and turning

you must be missing a washer or gasket that goes in the hose end, of the hose try teflon tape,this is all your plumber is going to do.

Some of the new units have stops installed on the valve itself. Make sure they are open.