WIRSBO TELASTATS ( MOTORIZED VALVE ACTUATOR

HEY EVERYONE. I INSTALLED A LARGE RADIANT FLOOR HEATING SYSTEM 4 YEARS AGO. WE SERVICE THE BOILER EVERY YEAR AND NEVER HAVE HAD ANY PROBLEMS WITH THE SYSTEM. MY PROBLEM IS THE OWNER CALLED AND SAID THAT ONE OF THE TELASTATS LOOKED BROKEN. I ORDERED ONE AND WENT TO REPLACE AT HIS HOME, WELL FURTHER INVESTIGATION I HAVE FOUND THAT I HAVE 5 MORE THAT SEEM TO BE BROKEN OR COMING APART. THE MOTORS ARE FINE, BUT WERE THEY ATTACH TO MY MANIFOLDS THE SEEM TO BE BROKEN IN PIECES. HAVE OR DID I DO SOMETHING WRONG. IS THIS A NORM FOR THESE FROM WIRSBO. SHOULD I REPLACE WITH DIFFERENT BRAND! THE MANIFOLDS WERE BALANCED CORRECTLY ( I MESSURE EVERY LOOP BEFORE POURING OF FLOORS WITH A ROLLING TAPE. I TWEAK ALL MY SYSTEMS WITH IN A 3% MARGINE ( I AM VERY PICKY )