I've just had a combi boiler installed, and in anticipation of this, I bought a rather swish looking mixer shower - trouble is it doesn't work. Got loads of cold water coming through, but no hot at all. I swapped the connections over so hot supply going into cold etc, and got all hot and no cold. So I reckon it's theres a problem with the valve on the incoming hot water side. The place I bought it from are refusing to exchange ot for another, saying that my cold pressure my have been too great and may have ruptured an o-ring, and that I'll need to get a Bristan Engineer out to dismantle the mixer bar to check it. Any thoughts? Anyone else had a similar problem?