RHEEM EEMAX & ECOSMART 0.187A Fast-Acting Glass Fuse (3AG) HA-P028

The RHEEM EEMAX & ECOSMART HA-P028 is the OEM in-line glass fuse that protects the control board on larger Eemax HomeAdvantage II and ProAdvantage tankless electric water heaters. It sits in the external black fuse holder (not soldered to the board) and is the first line of defense when the display stays dark after breakers are turned on.

A correctly rated fast-acting fuse like this one opens quickly on a short or overload, which helps prevent a failed component from taking out the entire control board. Using the specified 0.187A 3AG fuse keeps protection matched to the board’s design instead of relying on a generic substitute that may trip too late or too often.

Features & benefits

• Fast-acting 0.187A (187 mA) glass fuse in standard 3AG size
• Protects the control-board circuit on 18–36 kW units that use an external fuse holder
• Quick-open characteristic helps limit damage if a short occurs on the low-voltage side
• Direct OEM replacement so fit and ratings match the original holder
• Inexpensive insurance that often restores power when the unit has no display or no heat after a power event

Dimensions

• Style: 3AG (AGC-style) glass cartridge
• Typical size: 1/4″ diameter × 1-1/4″ long (approx. 6.3 mm × 32 mm)
• Rating: 0.187A fast-acting

Compatibility

Use HA-P028 in the external black fuse holder on these models (and equivalent rebranded units):

• Eemax HomeAdvantage II: HA018240, HA024240, HA027240, HA036240
• Eemax ProAdvantage: PR018240, PR024240, PR027240, PR036240
• Eemax EEM240 series (blue units): EEM24018, EEM24024, EEM24027, EEM24036
• Rheem / Ruud / Richmond equivalents: RTEX-18, RTEX-24, RTEX-27, RTEX-36 and matching RETEX / RMTEX models
• EcoSmart / iHeat-style 18–36 kW units that use the same external holder

Note: This is not the ceramic board-mounted fuse (that part is typically HA-P092 / 0.2A slo-blo). Confirm you are replacing the fuse in the black in-line holder.

Always shut off all breakers and verify zero voltage before replacing the fuse. If the new fuse blows immediately, the board or another component still has a fault and should be diagnosed before further operation.