Description
Trade replacement for Rheem standard-NOx, 2″ insulation (Natural Gas, 4″ W.C.) standing-pilot tanks
The Honeywell/Resideo WT8840C1500 is a factory-style gas control built for Rheem water heaters that use a 2″ insulation cavity. It reads tank temperature via an immersion-well NTC sensor, is self-powered by the pilot’s thermopile (no external wiring), and ships with a 4″ W.C. outlet-pressure setting for natural gas.
Replaces these Models
- Honeywell/Resideo WV8840C1605
- Rheem AP16910B
- Rheem SP20832B
What it Does Well
OEM-Specific Fit
Designed as the trade replacement for Rheem standard NOx water heaters a 2″ cavity. This ensures proper fit, mounting, and compatibility without modification.
Accurate Temperature Control
Uses an immersed NTC sensor in a sealed well for precise, consistent water temperature measurement.
Integrated Safety Features
Built-in temperature cutoff (ECO) around 189°F to shut off gas in case of overheating. The flame-sensing pilot system ensures burner only operates with a proven flame.
Pressure Regulation
The factory-calibrated regulator at 4″ W.C. outlet pressure is matched to Rheem system requirements for proper gas flow and safe operation.
Self-Powered, Standing-Pilot Design
Runs on thermopile output from the pilot flame; no batteries or 24-V supply required.
Key Specs
| Gas & Regulator Setting | Natural gas; 4.0 in. W.C. outlet pressure. |
| Cavity / Fit | 2″ insulation Rheem standard-NOx tanks; upright mounting. |
| Connections | ½ in. NPT inlet × ½ in. inverted-flare outlet (90° body pattern). |
| Power from Pilot | Thermopile 350–850 mV DC (open circuit). |
| Temperature Ranges | Dial set-point 55–155 °F; ECO high-limit trips at 189 °F; ambient 32–150 °F. |
| NG Capacity | 30,000–85,000 BTU/h |
Performance Insights
