[phil1983]

I've searched all the forums I can find to see if I can identify my problem and fix it but haven't had any luck so I thought I'd try posting to see if someone out there can help

I live in a 2 story town house and the shower is upstairs. Whenever the hot water is turned on to a slow flow I get a constant shuddering sound behind the tap and the water spits out in a regular machine gun like flow. If I turn up the flow it runs smoothly. The cold water is not effected at all.

We have quite high water pressure and from what I've read that could be the problem. Here are a few things that I have tried/discovered.

When I start the shower vibrating then turn on the hot water at the sink next to it the vibrating stops. While I'm turning on the sink tap I can actually feel the vibrations coming though it :/

I've turned off the water flowing into the hot water system then run the shower until the water runs out but this hasn't helped.

I've also turned down the flow of water into the hot water system but I can't see a way to control the flow coming out.

I took the handle and flange of the tap to see if I could see anything but the spindle goes through the wall and is sealed with silicon so I couldn't see in behind it.

The house and plumbing is about 15-20 years old.

Can any one help me with this problem?

Thanks

[hkstroud]

First where are you located? The term tap is more common in the UK or EU than in US.

For your information.

I've also turned down the flow of water into the hot water system but I can't see a way to control the flow coming out.

That is usually the only valve on a water heater. Its purpose is to turn the water to the heater off. Not for volume control. You could use it to control the volume but you would have to turn it almost off because the pipe is 3/4" and the pipe to the tub is 1/2"

When I start the shower vibrating then turn on the hot water at the sink next to it the vibrating stops. While I'm turning on the sink tap I can actually feel the vibrations coming though it :/

When you do that you change the pressure and the volume of the water to the tub.

What it sounds like to me is that you have a loose washer in the shower hot water stem. With a certain water pressure and flow that washer moves and changes the flow and causes the pipes to vibrate. There could be some debris in the hot water valve that moves under a certain pressure. When you open the sink faucet that changes the pressure and volume to the shower, therefore the washer stops vibrating.

I took the handle and flange of the tap to see if I could see anything but the spindle goes through the wall and is sealed with silicon so I couldn't see in behind it.

Repair is to remove the stem and replace the washer or flush out the debris. This is not difficult but you will need a set of tub and shower wrenches. At this point I am assuming that the silicon is just someone's attempt to prevent water getting inside the wall.

Show us a picture with the handle and flange removed.