The Pentair Tube Sheet Coil Assembly Kit (474059) is the OEM replacement heat exchanger assembly for the MasterTemp 250NA and 250LP gas heaters. This kit includes Item No. 3 O-Rings from the MasterTemp 250 parts diagram — the complete tube sheet coil assembly required to restore full heating function to your MasterTemp 250 heater.
⚠️ IMPORTANT: KIT LISTING
This listing is a kit containing the complete Tube Sheet Coil Assembly (Item No. 3, O-rings). Confirm the item number against your MasterTemp 250 parts diagram before ordering.
⚠️ IMPORTANT: LICENSED PROFESSIONAL INSTALLATION 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.
The tube sheet coil assembly is the primary heat transfer component inside the MasterTemp 250 heater. Pool water circulates through the coil while combustion gases pass over the exterior, transferring heat to the water. A failed or leaking coil assembly results in loss of heating efficiency, water loss, or contamination of the combustion chamber — replacement restores the heater to factory heating performance.
Specifications
| Pentair Part Number |
474059 |
| Part Name |
Tube Sheet Coil Assembly Kit |
| Quantity Included |
Kit (includes Item No. 3) |
Fits Into
| Brand |
Equipment Line |
Model / Part Number |
Notes |
| Pentair |
MasterTemp 250 — MasterTemp Series |
250NA |
Includes Item No. 3 (O-rings) |
| Pentair |
MasterTemp 250 — MasterTemp Series |
250LP |
Includes Item No. 3 (O-rings) |
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
Before ordering, cross-reference Item No. 3 on your MasterTemp 250 exploded parts diagram to confirm this is the correct assembly for your heater's configuration. The 250NA is the natural gas model and the 250LP is the propane model — confirm your fuel type matches your existing heater before proceeding. Because the heater must be fully drained and the combustion chamber accessed for this repair, have your licensed pool technician inspect the header, manifold, and associated seals for wear while the heater is open — replacing worn components in a single service visit avoids repeat labour costs.
