The White Rodgers 37C72U is a thermostat control for LP gas water heaters, featuring a fixed adjustment main regulator and adjustable pilot pressure. It ensures safe operation with tamper-resistant screws, manual reset mechanisms, and temperature settings including "VERY HOT" and "HOT". Designed for professional installation only, compatible with LP gas systems (left-hand outlet thread). Below are the key specifications, installation, operation, and troubleshooting instructions.
Assemble tools: flat blade screwdriver, adjustable wrench, soapy water solution for leak testing, hose for draining. Shut off gas and water supply to water heater until installation complete. Label connections before disconnecting. This control is for LP gas water heaters only; not for natural gas. Drain water from heater before starting. Professional installation required.
WARNING! Failure to read and follow all instructions carefully before installing or operating this control could cause personal injury and/or property damage. Save these instructions.
The 37C72U is a gas control valve and thermostat for water heaters, with fixed main regulator and adjustable pilot pressure. It includes a temperature dial with "VERY HOT" and "HOT" settings, igniter button for pilot lighting, and tamper-resistant screws. Knob positions: OFF, PILOT, ON. Designed for safe operation with odorant detection for gas leaks. Left-hand outlet thread for LP gas.
Applications: LP Gas Water Heaters Only; Not for Natural Gas.
CAUTION! Installation and service by professionals only. Do not force knob; replace if stuck. If knob doesn't pop up in PILOT, replace control. Tamper-resistant; do not repair/adjust. Use gas detector if odorless gas suspected. Set to lowest safe temperature to avoid scalds (160°F at "VERY HOT").
WARNING! Do not use on natural gas; risk of CO poisoning, fire, explosion. If smell gas: Do not light appliances, no switches/phones, call gas supplier/fire dept. Check for leaks with soapy water, not flame.
Shut off gas to water heater. Shut off cold water inlet. Connect hose to drain cock, drain to nearby drain; open hot faucet. Remove outer door. Pull off control knob. Remove screws holding thermostat to gas control. Disconnect wires from old control. Remove old control from gas control.
Shut off gas and drain water as above. Remove old control. Install new 37C72U: Apply pipe joint compound to male threads (leave first two threads clean), install in tank. Connect gas lines, wires, manifold. Check for leaks with soapy water (supply line, control to manifold, pilot tube). Affix new lighting label over old. Restore water, light pilot.
Terminal Designations: Wires to gas control valve; igniter connections.
Gas Connections: Inlet to gas supply, outlet to manifold (left-hand thread), pilot tube to burner. No electrical wiring beyond igniter.
CAUTION! Test all connections for leaks before lighting. Use soapy water only.
After installation, light pilot and set temperature. Verify no leaks and proper ignition.
Not applicable; water heater control without fan.
Not applicable; water heating only.
Non-programmable mechanical control. Set temperature via dial after lighting pilot.
Adjust pilot pressure if needed (professional only). Main regulator fixed. Affix lighting label. Ensure tamper-resistant screws in place. For LP gas only; verify gas type.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Knob won't turn | Damaged mechanism. | Replace control. |
| Knob doesn't pop up | Damaged spring. | Replace control; shut off gas. |
| Gas leak detected | Loose connections. | Do not light; call professional. |
| Pilot won't light | Gas supply off, leaks. | Check supply, test leaks with soapy water. |
| Scald risk | High temp setting. | Lower dial; set to lowest safe. |