Overheat thermostat - Worcester Bosch 350

hello Advice or insight sort. Our Worcester Bosch 350 combi boiler has developed an intermittent problem. After the hot water has been running for a time, eg. after a shower, the overheat thermostat pops up and ths system shuts down. Doesn't happen when the heating has been running for a long time, only with the hot water. Doesn't happen everytime the hot water is used. Any ideas what's wrong?
bella2002tii
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On Tue, 09 Jan 2007 14:36:55 -0800, bella2002tii wrote:

I'm not familiar with this model but my first guess is the heat exchanger getting scaled up, if you're in a hard water area. Is the flow of hot water not as good (but possibly hotter) than it used to be?
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