Manual-backed troubleshooting
RV Water Heater Not Heating? Separate Gas and Electric Modes
For an identified combination tank model with a confirmed full tank, record gas-only and electric-only behavior using the installed normal controls. One working mode makes the service brief more useful; neither working mode is a different route.
Safety first
Leave immediately if you smell propane, a propane or carbon monoxide alarm sounds, you see smoke or soot, or you smell ammonia. Do not operate switches, appliances, fans, phones, or other ignition sources. From a safe location, call 911, the fire department, or your propane supplier. Do not return until a qualified professional says it is safe.
Things you can try first
These checks use normal controls and owner-accessible areas. Stop immediately when a listed stop condition occurs.
Confirm the exact model and available energy modes
Use RV records or an already-visible label to record the manufacturer, full model, serial number, tank type, control type, and whether the installed appliance actually supports gas, electric, or both modes.
Source
Source: Suburban printed pages 3-7 and model locator; Dometic printed pages 5-6 and 15-16
Record gas-only and electric-only results using normal controls
For a confirmed combination model with a full tank, observe one normal request in each installed mode. Record the switch state, indicator, sound, and whether useful heat follows. Do not repeat a failed mode or operate an unsupported mode.
Source
Source: Suburban printed pages 4-7; Dometic printed pages 15-16
Observe only a cool, visible exterior area
From a safe position, record soot, leakage, visible damage, or material covering a documented exterior airflow opening. Do not touch a hot surface, insert a tool, remove a cover, or reach inside.
Source
Source: Suburban printed page 8; Dometic printed pages 15-17
Check your manual first
Only continue when your exact installed equipment and its documentation make this owner-accessible action clear.
Use the Suburban reset only for its confirmed lockout state
If the exact appliance is a Suburban tank heater governed by Guide 206244 Rev A and its red RESET indicator shows gas lockout, continue to the dedicated reviewed reset page. Do not apply that action to slow heating, electric-only failure, another brand, or another control state.
Source and when to stop
Source: Printed page 5, gas operation and lockout
Stop if: The state is slow heat or electric-only failure rather than gas lockout; The reset was already attempted; Lockout returns; Normal ignition still fails.
When this needs a technician
Use one normal observation per installed mode after exact identification and tank-fill confirmation. Stop for repeated lockout, electrical trips, leakage, soot, or emergency signs.
Gas mode does not heat but electric mode does
Stop and route to serviceRecord a gas-mode-specific failure and any lockout indicator. On a combination model, this is useful service evidence but not proof of a propane, ignition, valve, electrode, board, thermostat, ECO, or wiring fault.
Source: Part Number 206244, Revision A, 03-22-2023, Form 3317866.000, Revision A, 08/22
Electric mode does not heat but gas mode does
Stop and route to serviceRecord an electric-mode-specific failure and the exact installed switch arrangement. Do not access a 120-volt element, junction box, wiring, breaker internals, thermostat, or ECO through this page.
Source: Part Number 206244, Revision A, 03-22-2023, Form 3317866.000, Revision A, 08/22
A combination model heats slowly with both controls selected
Stop and route to serviceOn covered Dometic combination models, gas can be locked out while electric operation continues, so the lockout lamp may not appear until the electronic control is turned off. Record the exact control and recovery behavior; do not diagnose an internal gas component.
Source: Form 3317866.000, Revision A, 08/22
A confirmed Suburban tank heater shows red RESET
Manual-specific owner actionFor a model governed by Guide 206244 Rev A, use the dedicated reviewed Suburban reset page for one bounded interior-switch action. Do not use an exterior ECO procedure or apply the reset to another model or control state.
Source: Part Number 206244, Revision A, 03-22-2023
Neither documented mode heats
Stop and route to serviceFirst keep the unit off unless its tank is confirmed full through the RV manufacturer's normal fill procedure. If the tank is full and neither mode heats, record the controls and route to the exact manual or qualified service rather than combining gas and electrical diagnosis.
Source: Part Number 206244, Revision A, 03-22-2023, Form 3317866.000, Revision A, 08/22
The model is tankless, standing-pilot, or otherwise outside this source scope
Stop and route to serviceStop using these tank-heater mode routes. Record the exact model and use its current owner manual. Do not infer a control sequence from a similar-looking exterior door or switch.
Source: Suburban support page, reviewed 2026-08-07, Part Number 206244, Revision A, 03-22-2023, Form 3317866.000, Revision A, 08/22
Soot, leakage, hot-water release, odor, alarm, or smoke appears
Stop and route to serviceStop. Follow the emergency gate for odor, alarm, smoke, fire, soot, or suspected exhaust entry. Keep a leaking, damaged, or unexpectedly releasing appliance off and arrange qualified service.
Source: Part Number 206244, Revision A, 03-22-2023, Form 3317866.000, Revision A, 08/22
Time to call a tech
Stopping here protects the RV and gives the technician a clearer starting point.
Propane odor, an alarm, smoke, fire, soot, or suspected exhaust entry occurs.
Follow the emergency gate. Leave first and contact emergency services, the gas supplier, or qualified service from a safe location. Do not resume operation until the RV and appliance are cleared.
A mode locks out, fails again, or does not match the exact manual's control behavior.
Keep the failed mode off and arrange manufacturer-authorized or qualified RV service. Report the exact model, selected mode, indicator state, and whether the other mode heats.
Neither mode heats, tank-fill state is unknown, or a breaker or fuse trips.
Keep the appliance off and arrange qualified service or exact-manual support. Internal electrical, gas, and pressure-system diagnosis is outside this page.
Leakage, damage, unexpected hot-water release, or a pressure-system concern is present.
Keep the appliance off, keep people away from the affected area, and arrange qualified RV service. This page does not authorize tank, drain, or pressure-component work.
Before you call for service
Make a clear service brief
Record these details without repeating failed starts, opening a service cover, touching a hot surface, or draining a tank.
- Manufacturer, full model, serial number, tank type, and manual revision
- Installed gas/electric modes and exact switch arrangement
- Gas-only result and indicator state
- Electric-only result and indicator state
- Whether both controls were selected when slow recovery occurred
- Whether the tank was confirmed full
- Any prior manufacturer-authorized reset and its result
- Any soot, obstruction, leak, hot-water release, odor, alarm, smoke, abnormal sound, or breaker/fuse trip
Quick reference
Common questions
Why does my RV water heater work on electric but not gas?
That is a gas-mode-specific failure on a confirmed combination model. Record the exact control and lockout state, then use the exact manual or qualified service. The mode split alone does not identify an ignition, propane, valve, electrode, or board fault.
Why does it work on gas but not electric?
Record an electric-mode-specific failure and the exact installed switch arrangement. Do not access the 120-volt element, junction box, wiring, thermostat, ECO, or breaker internals through a generic guide.
Why is hot-water recovery slow when both modes are on?
On covered Dometic combination models, electric operation can continue while gas is locked out, and the lockout lamp may not show until the electronic control is switched off. Record the behavior and route it to the exact manual or service rather than diagnosing a part.
Primary documentation
Sources and revision record
Suburban Tank Water Heaters Operation & Maintenance Guide
Part Number 206244, Revision A, 03-22-2023
Reviewed: August 7, 2026
Relevant sections: Printed pages 3-9: safety, gas/electric controls, lockout, full-tank requirement, soot and screen observations, and service routing
L.P. Gas Water Heater Installation and Operation Manual
Form 3317866.000, Revision A, 08/22
Reviewed: August 7, 2026
Relevant sections: Printed pages 2-6 and 15-17: safety, service boundary, model identification, gas/electric controls, mode-specific lockout, full-tank warning, and service routing
Where's My Model Number?
Suburban support page, reviewed 2026-08-07
Reviewed: August 7, 2026
Relevant sections: Suburban Water Heater (SW | V | SAW Models) and IW60 Tankless Water Heater
Revision note: Third-pass minimal revision: restores a direct gas-versus-electric question while retaining the removal of gas, electrical, element, ignition, and pressure-system diagnosis.
Sources last reviewed: August 7, 2026