MasterTemp 125 Tubesheet Coil Assembly The Pentair MasterTemp 125 Tubesheet Coil Assembly (474971) is the OEM replacement heat exchanger core for the MasterTemp 125 low-NOx gas heater. ⚠️ IMPORTANT: HEATER COMPONENT — PROFESSIONAL SERVICE REQUIRED Gas and electrical heater components must be serviced by a licensed pool professional or qualified HVAC technician. Do not attempt to service gas or high-voltage components without proper certification. ⚠️ IMPORTANT: VERIFY FITMENT BEFORE ORDERING Neither the Pentair 2025–2026 parts catalog nor compatibility records for part number 474971 are available in the current database extract. Confirm this part number against your MasterTemp 125 heater's installation manual or the original component before ordering. The tubesheet coil assembly is the primary heat transfer component inside the MasterTemp 125 heater. Pool water circulates through the coil tubes while combustion gases pass over the external tube surface, transferring heat into the water stream. When the coil develops a leak or suffers corrosion damage, water can enter the combustion chamber and contaminate the heat exchanger cavity — replacing the full tubesheet coil assembly restores the sealed heat transfer pathway and protects the surrounding heater components. Specifications Pentair Part Number 474971 Pro Tip Before ordering, locate the part number stamped or labeled on the existing coil assembly inside your MasterTemp 125 heater and confirm it matches 474971. MasterTemp heaters are available in multiple BTU ratings — coil assemblies are not interchangeable across models. If your heater's data plate does not confirm the 125 BTU rating, verify the correct part number in your heater's installation manual before proceeding.
