Whale SL3501, SL3511, SL5501, SL5511, SL5601, SL5611, SL6501, SL6511
Official Whale operating instructions and troubleshooting for the Heat Air 3 GT/4 GT/5 GT underfloor space heater range. Whale's current branding for this range's control panel/interface is "Heat Control" (distinct wording from the unit's own "Heat Air" model family name, confirmed via Whale's own site) - some vehicle handbooks (Elddis's 2026-model-year documents) refer to the system by this control-panel name instead.
Technical Specifications
Master Troubleshooting & Diagnostics Matrix
| Error Code / Indicator | Symptom / Meaning | Possible Cause | Step-by-Step DIY Fix | Suggested Actions |
|---|---|---|---|---|
1 | Inadequate gas supply | Insufficient gas pressure or lack of gas supply | Check gas supply, ensure 30mbar LPG is available, and proceed to step 4 to clear the lockout. If the issue remains unresolved, contact an authorized service agent. | DIY Check / Tech Fallback |
2 | Overheat | Heater exceeded normal operating temperature due to restricted airflow | Make sure the air vents and ducts aren't restricted, then give the heater 10 minutes to cool before moving to step 4 to clear the lockout. Contact an authorised service agent if the fault persists. | DIY Check / Tech Fallback |
3 | Inadequate supply voltage | The DC supply voltage has drifted outside the heater's 10.5-15.9V operating range (it won't run at all below 10.1V). | Verify supply voltage is between 10.5 and 15.9V DC, and proceed to step 4 to clear the lockout. If the issue remains unresolved, contact an authorized service agent. | DIY Check / Tech Fallback |
4 | Flue blockage | Obstruction in the exhaust flue or combustion inlet | Check flues for blockages, clear any obstructions such as snow or debris, and proceed to step 4 to clear the lockout. If the issue remains unresolved, contact an authorized service agent. | DIY Check / Tech Fallback |
5 | Internal fault | Internal system error or component failure | Call Whale Support (+44 (0)345 9090 911) (in Europe, use the enclosed Webasto Service details instead) and move to step 4. This fault needs a repair or replacement carried out by an authorised service agent. | Professional Intervention Required |
6 | Control panel fault | Communication error or temporary glitch in the control panel | Power off the unit, power on the unit, and proceed to step 4 to clear the lockout. If the issue remains unresolved, contact an authorized service agent. | DIY Check / Tech Fallback |
7 | Multiple faults | Simultaneous or sequential system errors triggered | Power off the heater, check heater for recurring faults, power on, and proceed to step 4 to clear the lockout. If the issue remains unresolved, contact an authorized service agent. | DIY Check / Tech Fallback |
Frequently Asked Questions
Q: Can I fit a Heat Air heater myself?
If you're technically minded, yes - each Heat Air kit includes a detailed step-by-step installation guide. Otherwise, a local motorhome workshop should be able to fit it for you. Whoever fits it, a qualified gas engineer has to certify any gas work to BS EN 1949-2011.
Q: Which Heat Air model should I choose?
The models differ in heat output and fuel type, with options for both campervans and panel-van conversions - broadly, the bigger the vehicle, the more output you'll want. Gas-only suits off-grid touring; if you mostly stay on sites with hook-up, the gas-and-electric version adds 3kW of electric heating.
Q: Will Heat Air work when I'm off-grid?
Yes. Every Heat Air model can run on gas, and on its low gas setting it draws very little from the battery - as little as 0.6 A.