Description
The Pentair Air Orifice Kit (77707-0113) is the OEM replacement air orifice assembly for the MasterTemp 400 gas heater, covering both natural gas (400NA) and liquid propane (400LP) configurations.
IMPORTANT: KIT LISTING INCLUDES ITEMS 6 AND 7
This listing is a kit, not a single orifice. It includes Item Nos. 6 and 7 from the MasterTemp 400 exploded parts diagram. Confirm both components are required before ordering.
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.
The air orifice assembly meters the gas-to-air mixture entering the burner tray of the MasterTemp 400 heater. A damaged, corroded, or incorrectly sized orifice disrupts combustion efficiency and can cause ignition failure, incomplete combustion, or nuisance lockouts. This kit restores the factory-calibrated airflow specification for the 400 model’s burner system.
Specifications
| Pentair Part Number | 77707-0113 |
| Part Name | Air Orifice Kit Model 400 |
| Contents | Includes Item Nos. 6 and 7 (per MasterTemp 400 parts diagram) |
| Quantity Included | Kit (Each) |
| Compatible Heater Models | MasterTemp 400NA, MasterTemp 400LP |
Fits Into
| Brand | Equipment Line | Model / Part Number | Notes |
| Pentair | MasterTemp MasterTemp Series | 400NA | Air Orifice Kit for 400 Model Only (includes items 6 & 7) |
| Pentair | MasterTemp MasterTemp Series | 400LP | Air Orifice Kit for 400 Model Only (includes items 6 & 7) |
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
The MasterTemp 400 is available in both natural gas (400NA) and liquid propane (400LP) configurations confirm your heater’s fuel type before ordering any burner or combustion component. The model designation is printed on the heater’s rating label, typically located on the front access panel or inside the front door. Natural gas and LP orifice kits are not interchangeable; installing the wrong orifice for your fuel type creates a combustion hazard and will void the heater’s service record. If the original orifice shows corrosion, physical damage, or the heater has been exhibiting ignition lockouts, replacing this kit as part of a scheduled burner service is the correct course of action have a licensed pool or HVAC technician confirm the diagnosis before parts are ordered.
