Does anyone experience problems with these? Over the last year I have been called out to about 6 leaking Firebird boilers and 3 leaking Warmflow boilers and one leaking (old) Trianco boiler, with 3 of the Firebirds in the last month? I find evidence of leaks in several places. Usually seems to be the connections onto the boiler water jacket, the ball type pump valves and the connections to the plate heat exchanger.