I agree with Rodan, to much radiator flow. Brink must verify that the
thermstate was installed the right way, sounds like the customer
duplicated the first problem. Buy not putting in the correct
thermostste or installed it wrong. Buy cutting the flow of the
radiator hose you acted like the thermostate. I would have the
customer come in and remove the stat and verify his work. If you do
not find a problem just do not charge. My guess is that you will find
the problem, wrong stat or installed wrong.