40 Gal. Short Water Heater, Residential, LPG, 31,000 BTU

Rheem Professional Classic 40-Gallon Short Liquid Propane Water Heater – 31,000 BTU, Atmospheric Vent

The Rheem PROG40S-31P-RH62 is a 40-gallon short-profile liquid propane water heater designed for residential applications with spatial constraints or limited vertical clearance. Featuring a 31,000 BTU/hr burner and a 31.3 GPH recovery rate at a 90°F rise, this unit offers reliable hot water output for small to mid-sized household demands. The model is part of Rheem’s Professional Classic series, engineered to meet NAECA 2015 efficiency standards.

This unit incorporates a push-button pilot ignition system, low-NOx burner assembly, and an electronic gas control with self-diagnostic capabilities. A glass-lined tank and magnesium anode rod provide internal corrosion protection, while the maintenance-free air intake system minimizes service requirements over the life of the unit.

Technical Specifications

• Fuel Source: Liquid Propane (LP)
• Nominal Capacity: 40 gallons
• Input: 31,000 BTU/hr
• Recovery Rate: 31.3 GPH at 90°F rise
• Uniform Energy Factor (UEF): 0.62
• Venting Type: Vertical atmospheric, 3” or 4” B-vent
• Ignition System: Push-button pilot with electronic gas control
• Water Connection: 3/4" NPT (top-mounted)
• Tank Protection: Fused glass lining with magnesium anode rod
• Diameter: 21 inches
• Height: 52-1/8 inches
• Warranty: 6-year limited warranty on tank and parts

Installation Guidelines

The PROG40S-31P-RH62 is intended for indoor installations using vertical atmospheric venting systems. It is suitable for replacement projects and new construction where low ceiling height is a factor. Combustion air must be available per code, and venting must comply with B-vent termination and slope requirements. The unit does not require electrical power and is factory-configured for LP fuel. Proper gas line sizing and local code adherence should be verified before installation.

Contractor Use Case

This model is well-suited for confined utility spaces, crawlspaces, or mechanical closets. The compact form factor and standard water/gas connections simplify replacement in existing installations. Built-in diagnostic LEDs aid with service calls, and the maintenance-free combustion air intake reduces upkeep over the product’s service life.