Picked up the part from the supply house. Arrived at the job, greeted Carlise and proceeded to perform the repairs to the HTP Combi boiler. I opened the cabinet with the parts box. I look at the new part and performed a visual inspection to match up the replacement part on the boiler. The parts were different. I called HTP tech support and was given a different parts number for the unit in question. I explained the issue to the Customer and he was understanding. I called FraBar to make him aware of the ongoings. Drove back to the supply house and processed the exchange for the correct part to arrive asap. I called the customer to keep him in the loop. He was okay with everything. Carlise is satisfied with the service, so far.