Grohe thermostatic mixers

[onlyasking]

in the middle of a loft conversion...so the plumber drains the hot water tank and the cold tank through these taps- now the taps dont mix the hot and cold - only cold comes through. is there any chance debris from the tanks can stop the mixer working.? Also can it be repaired ? is there a service kit..?
sorry for all the questions... just want to get this sorted.

thanks

 

[kevplumb]

dont know if you can get a kit sounds like an airlock to me
is hot water running cold or not running at all ?

 

[onlyasking]

bump...