The check valve in the inlet connect from the boiler supply line is making the noise. To prove a point, put an ice cube on the radiant supply sensor which should make the injection pump speed up. If the noise goes away when the pump speeds up, then it is the check.
   To eliminate the noise, break the hot water supply connection and unscrew the adaptor fitting from the block manifold. Look inside that connection and you should see the check and a snap ring holding it in place. Remove the snap ring and then the check. Reinstall the adaptor fitting and re-splice the copper tubing.
   This noise problem has occurred once in a while and we are developing a new check that should overcome it. At this time, this is our only solution and I have not heard of any problem operating without the check.

NO, the control will only try to maintain a constant differential temperature as the temperature is the system rises.