Pentair Coil/Tubesheet Sealing O-Ring Kit | MasterTemp 125 Heater | 474973
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- SKU:
- 474973
-
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About This Item
The Pentair 474973 is the OEM Coil/Tubesheet Sealing O-Ring Kit for the MasterTemp 125 Heater — the correct replacement when servicing the internal sealing surfaces where the heat exchanger coil meets the tubesheet assembly.
⚠️ IMPORTANT: KIT LISTING — MULTIPLE O-RINGS INCLUDED
This listing is a kit, not a single O-ring. It contains the complete set of coil/tubesheet sealing O-rings required for a full service of the MasterTemp 125 heat exchanger assembly.
⚠️ IMPORTANT: HEATER SERVICE — LICENSED PROFESSIONAL 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: LUBRICATION REQUIRED — SOLD SEPARATELY
Always lubricate these O-rings with a silicone-based lubricant before installation. We carry the Pentair R172351 Lifeguard® Silicone Lubricant — the OEM-matched product for Pentair equipment.
The coil/tubesheet sealing O-rings form the critical pressure boundary between the heat exchanger coil and the tubesheet in the MasterTemp 125 combustion and water circuit. When these O-rings degrade, water can migrate past the sealing surfaces, leading to leaks at the heat exchanger assembly. Replacing the full kit restores the integrity of this seal and is the correct service procedure when the heater is opened for heat exchanger inspection or coil service.
Specifications
| Pentair Part Number | 474973 |
| Part Name | Coil/Tubesheet Sealing O-Ring Kit |
| Part Category | O-Rings |
| Quantity Included | Kit |
Fits Into
| Brand | Equipment Line | Model / Part Number | Notes |
| Pentair | MasterTemp 125 Heater — MasterTemp Series | MT125 | Coil/Tubesheet Sealing O-Ring Kit for MasterTemp 125 |
| Pentair | MasterTemp 125 Heater — MasterTemp Series | MASTERTEMP 125 | Also included in Items 1 and 2 |
Compatibility is based on Pentair parts documentation and available OEM records. This is not an exhaustive list. For certainty, verify the part number in your equipment's manual or on the original part itself before ordering.
Pro Tip
When the MasterTemp 125 is opened for heat exchanger service, replace the full coil/tubesheet O-ring kit rather than individual rings — partial replacement leaves aged seals in place that are likely to fail shortly after. Before installing each O-ring, apply a thin, even coat of Pentair R172351 Lifeguard® Silicone Lubricant to help each ring seat correctly and prevent tearing during assembly. Never use petroleum-based lubricants — they will degrade rubber O-rings and shorten service life significantly.
