Just to be clear, your oil boiler is OK to operate in cold start, correct? Also, you are changing the low limit at the Aquasmart, not the Tekmar? They appear to have several features that overlap. What I am wondering is if the Tekmar is sending a "Stage 2" burner signal. When you flipped the switch to run the oil boiler for us manually, was there a "2" on the Tekmar display? I wonder if there is a time delay between stages 1 and 2.