OEM Replacement Heat Exchanger Coil for MasterTemp HD Series Heaters
The Pentair 77707-0244 is the OEM Cupro Nickel Tube Sheet Coil Assembly Kit for the MasterTemp HD Series heater water system, confirmed for use on the 400HDNA and 400HD-LP models (manufactured before 1/13/09).
⚠️ IMPORTANT: KIT LISTING
This listing is a kit assembly — not a single component. Confirm all included pieces are accounted for upon receipt before beginning service.
⚠️ IMPORTANT: VERSION-SPECIFIC PART — VERIFY BEFORE ORDERING
This assembly is for MasterTemp HD Series heaters manufactured before 1/13/09. Heaters built on or after that date require a different assembly. Check the manufacture date on your heater's data label 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 within the MasterTemp HD Series heater's water system. The cupro nickel alloy construction provides enhanced resistance to corrosion in aggressive water conditions — including salt water and water with elevated mineral content — compared to standard copper coil assemblies. Replacing a degraded or failed coil assembly restores proper heat transfer between the burner system and pool water circulation.
Specifications
| Pentair Part Number |
77707-0244 |
| Material |
Cupro Nickel |
| Capacity |
400,000 BTU |
| Quantity Included |
Kit |
| Version / Date Qualifier |
For heaters manufactured before 1/13/09 |
Pro Tip
Before ordering, locate the manufacture date on your heater's data label — typically found on the inside of the front door panel or on the heater cabinet. This assembly is specific to units built before 1/13/09. If your heater was manufactured on or after that date, consult your equipment manual or contact us to identify the correct replacement assembly for your unit.
