Is the HOT/COLD pressure the same @ the shower (While flowing)? Sounds like you have a flow restriction on the hot water side of the shower - possible swarf/grit has found its way to a screen on the hot side shower valve? It may help to think of Pressure as Voltage, and Flow as current. Narrowed lines/blockages act like resistors. >>> rhprosser@gmail.com 24 Mar 08 02:58:04 >>> On 24/03/2008, Bob Blick wrote: > > I'm having a similar problem at the moment with a pressure reducing valve. If I adjust it for reasonable pressure in the upstairs shower, it eventually develops a slow leak and I start losing hot water through the overflow. If I back off the pressure to stop the overflow, then we get cold showers. A new washer generally fixes the problem for about 6 months but that''s it. Not sign of grit or damage to the sealing face where the washer sits. I've tried sanding the surface of the washer which removes the hard oxydised surface and it appears to help but it doesn't last We first noticed the problem when the council fitted a water meter and there was grit/swarf in the system but that was a long time ago and it now appears clean. One solution appears to be to increase the height of the overflow so more back pressure will develop before it starts to drip. This will apply more pressure to the valve & hopefully turn it off harder. But I'm already close to the maximum pressure of the hot water cylendar. The good side of things is that it's an easy job to replace the washer. Any ideas? Richard P -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist Eoin Ross Industrial computer support and design CHEMSTATION INTERNATIONAL http://www.chemstation.com 3400 Encrete Lane Ph 937 294 8265 Ext 1109 Dayton Fax 937 534 0368 Ohio 45439 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist