By Sta-Rite
Part # 6290-423
Manufacturer Code 77707-0209
Pentair® Sta-Rite® Manifold Internals 400K (Max-E-Therm) – 77707-0209 Key Benefits
✅ OEM Replacement – Genuine Pentair® part designed specifically for 400K Max-E-Therm and MasterTemp heaters
✅ Restores Performance – Rebuilds efficient gas flow and combustion inside the manifold
✅ Complete Internal Kit – Includes bypass valve, springs, and hardware needed to restore heater operation
Applications
✅ Compatible with Pentair® MasterTemp® and Sta-Rite® Max-E-Therm® heaters, 400K BTU models
❌ Not for 200K or 333K models (use the correct size kit for those heaters)
Tech Tips
⚠️ Check the manifold body — if it is cracked or corroded, you will need the full manifold replacement kit, not just the internals
✅ Direct fit design makes installation straightforward for service techs or experienced DIYers
⚠️ Always shut off gas and power to the heater before disassembly for safety
Specifications
✅ Part Number: 77707-0209
✅ Heater Size: 400,000 BTU
✅ Weight: ~1 lb
✅ Install Type: Internal rebuild kit only
What’s Included
✅ Internal manifold assembly with bypass valve
✅ Springs and hardware
❌ Manifold body (sold separately)
❌ Complete heater unit (sold separately)