Customer has no heat in the bathroom zone. We need to do diagnostic work to determine the cause. Radiant systems are difficult and time consuming to diagnose do to a lack of load calculations and labeling which are not normally available. Customer approved the diagnostic. Confirmed that both pumps were drawing the correct amount of amps, boiler was operating as it should. Noticed a small leak on one of the manifolds addressed this with the customer. Removed and tested the zone actuator for the bathroom. With actuator removed the zone was heating properly, with actuator in place no heat was present on the pipes. Presented pricing to replace the customers actuator. Customer approved. Began work by removing existing actuator, unwiring it at the zone valve control, installed new actuator and rewired it up, Gave bathroom a call for heat and measured temperatures on the supply and return. Informed customer that it would take a long time for the bathroom to warm up considering the outside te