The Mueller Streamline RP18115 3/8″ OD FTG Hermetically Sealed Sight Glass Moisture Indicator is a Mueller Streamline moisture indicator for HVAC repair and replacement work. Use it when the part number RP18115 and the listed specifications match the equipment being serviced.

This product is a 3/8″ OD FTG Hermetically Sealed Sight Glass Moisture Indicator manufactured by Mueller Industries. Features: Operating Temperature: -40F – 185F / -40C – 85C Designed for maximum flow and minimum pressure drop Large viewing window and indicator for better visibility Provides accurate identification of system conditions Certifications: UL/cUL Recognized Conforms to EU Pressure Equipment Directive and UK Pressure Equipment Regulation

Key Specs

• Product Type: Moisture Indicator

Expert Verdict

Reviewed by the SuperArbor Pro Desk: choose this part when the existing component label and unit documentation match RP18115 and the spec set above. It is best suited for targeted HVAC service repairs where exact fitment matters more than broad universal compatibility.

FAQs

What is the Mueller Streamline RP18115 used for?

It is a moisture indicator for compatible Mueller Streamline HVAC equipment. Match the part number RP18115 and the equipment service literature before ordering or installing.

Which specs should I verify before purchase?

Verify the spec set shown for this part: Product Type: Moisture Indicator. The replacement should match the existing component and the unit documentation.

How do I confirm this is the right replacement?

Compare the part number RP18115, the moisture indicator description, and any unit model references with the original component and the service manual.

Is this an OEM-style replacement part?

Use it as a direct replacement only when Mueller Streamline documentation lists RP18115 or an approved equivalent for the unit being serviced.

Who should install this HVAC component?

A qualified HVAC technician should install and test the moisture indicator. Disconnect power first, follow lockout procedures, and confirm safe operation after replacement.

Safety and Installation Notes

Disconnect power before service. HVAC electrical and combustion-related components should be installed and tested by a qualified technician. After installation, confirm wiring, mounting, airflow or fluid routing as applicable, and normal system operation.