Product Overview

The Pentair 77707-0411 is a genuine OEM gas orifice kit for Model 400 (400,000 BTU) natural gas pool and spa heaters, such as the Pentair MasterTemp 400. The orifice meters natural gas flow to the burner, so it must match the heater's fuel type and BTU size. Use it to service the gas train on a 400K natural gas heater or to convert a 400K propane heater back to natural gas.

⚠️ Important Purchase Notice

This is a gas-train component. Gas conversion and gas-train service must be performed by a qualified gas appliance technician following Pentair's instructions and local fuel-gas codes. Inspect the shipment upon arrival and report damage promptly.

WARNING: This product can expose you to chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.

Ideal For

• Servicing the gas train on a Model 400 natural gas heater.
• Converting a 400K propane heater back to natural gas.
• Replacing a damaged or incorrect orifice.
• Pool heater service technicians.

Key Features

• Genuine Pentair OEM part, number 77707-0411.
• Natural gas orifice sized for 400,000 BTU heaters.
• Brass orifice with sealing O-ring.

Benefits

• Correct gas flow for clean, efficient natural gas combustion.
• OEM fit for a straightforward repair or conversion.
• Helps restore reliable ignition and full heating output.

Compatibility

For Model 400 (400K BTU) natural gas pool and spa heaters, such as the Pentair MasterTemp 400. Propane heaters and other BTU sizes use different orifices (the 400K propane orifice is 77707-0441). Confirm your heater's model number, BTU rating and fuel type from the rating plate before ordering.

Installation or Upgrade Context

Shut off gas and electrical power before service. Replace the orifice following Pentair's instructions, then leak-test all gas connections and verify proper gas pressure and combustion on startup.

What’s Included

• One natural gas orifice with O-ring for 400K heaters

Specifications

Warranty

Covered by a 60-day manufacturer warranty, subject to Pentair’s applicable terms. Contact Pentair for warranty claim instructions; Pool Supply Depot can provide proof of purchase.

Customer Q&A

Which heaters does this fit?

Model 400 (400K BTU) natural gas heaters, such as the Pentair MasterTemp 400.

Will it work on a propane heater?

No. It's the natural gas orifice. The 400K propane orifice is 77707-0441.

Can I install it myself?

Gas-train work should be done by a qualified gas appliance technician.