Hot to Cold Shower

Just Spent about 15k on a new bathroom and the shower goes from hot to luke warm in 2 minutes.
* Kohler Shower Faucet - Single Lever (Fairfax ) * Mixing Valve is K-304-K (Not sure if it is the one with Screw driver stops)
Any advice to fix this? I made the minor adjustments but all that did was change how hot the water came out initially.
Please help. Wife really wants to use the new shower! -jeff
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Jeff, So do you mean you can get hot out of it for two minutes, then it drops to luke warm and stays there for everafter? Does not get hotter or colder if you let it run for 10 for 20 minutes longer? Is this only at shower? Hot at other fixtures in this bath stay hot when turned on? You could quickly check for a cross connection by turning off the hot water tank. If you still get pressure on the valves hot side then you have the hot and cold tied together somewhere or a bad cartridge. The Fairfax is a pressure balanced valve, so if you shutoff the hot to the valve then you should get nothing from the hot or cold when you turn it on. If you do, then check for pressure on the hot side of a sink, if you have water then you have a cross connection. If no hot at sink then probably a bad cartridge.
--
Dale
The above is the opinion of the author only and not his spouse,
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Cartridge is clogged with crud left over from the plumbing work, remove, flush, clean the cartridge?
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DIP TUBE!

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