Aquabrass Thermostatic Value Problem

Hello,
Approximately 6 months ago we renovated our bathroom and installed an AquaBrass thermostatic valve and hand shower. The product worked great until the last couple of weeks where something has started to go wrong. There are 3 clear symptoms we have observed as a result of the problem:
1) When you first turn on the shower the water comes out extremely hot regardless of the temperature setting. This lasts for about 10 to 20 seconds and then the water cools off to a more normal temperature
2) After the temperature settles down the shower simply will not get very hot even with the temperature knob set all the way to the left
3) Elsewhere in the house we get hot water coming out of the cold water taps for about 10 seconds or so (regardless of whether the shower is on). I have traced the problem to the shower where my guess is that the thermostatic value is allowing hot water to flow through into the cold water pipes.
Up until a couple of weeks ago everything was working perfectly. No other plumbing changes have occurred in the house recently.
Any thoughts or ideas on what may be the problem and how it could be fixed would be greatly appreciated! Thanks for your time.
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As a follow-up for anyone who may read this in the future and have a similar problem, I resolved the issue by calling Aquabrass. They mailed me two check valves and a new cartridge/mixer at no charge. The parts were easy to replace and it resolved all the problems I listed below.
snipped-for-privacy@hotmail.com (Brent) wrote in message

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replying to Brent, bob wrote: I ran across the same problem I phoned them and picked up the parts I needed very easy to deal with.
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