Dometic Heki4 Plus
Official technical documentation and workshop diagnostics for Heki4 Plus.
Technical Specifications
Master Troubleshooting & Diagnostics Matrix
| Error Code / Indicator | Symptom / Meaning | Possible Cause | Step-by-Step DIY Fix | Suggested Actions |
|---|---|---|---|---|
N/A | The roof light won't open or close. | The batteries in the remote control are running low, vehicle power supply is interrupted, fuse is faulty, or remote control coding is faulty. | Replace the remote's batteries, check the vehicle's power supply, replace the 10A flat-blade fuse, or re-teach the remote by cutting and restoring power, then pressing '<' and '>' together while the red lamp flashes for around 30 seconds. | DIY Safe |
N/A | Closing the roof light makes the control lamp come on. | The roof light isn't seated properly in the runner wedges - either something's obstructing it (twigs, leaves), or the lock's out of position. | Remove any objects stuck between glass and frame, or adjust the lock by loosening four screws, repositioning guide rail (1) so the lock runs in it, and re-tightening the screws. | DIY Safe |
N/A | The blackout blind or flyscreen won't roll. | Dirt accumulation on the side guides. | Clean the side guides thoroughly. | DIY Safe |
N/A | The lighting does not work. | Low remote control batteries, interrupted vehicle power supply, blown fuse, or one/both lamps are faulty. | Replace remote control batteries (Type AAA), check vehicle 12V supply, replace 10 A fuse, or replace faulty lamps (12 V, 8 W). | DIY Safe |
N/A | The rain sensor isn't responding. | The rain sensor is heavily soiled. | Disconnect the power, then dry-wipe the rain sensor with a cloth. | DIY Safe |
Frequently Asked Questions
Q: What are Dometic rooflight panes made of, and why?
PMMA (acrylic). It's very clear and easy to form and shape with heat. Dometic says it looks like glass at half the weight and is around 30 times stronger, insulates well against heat and cold, and stands up to weather from -40°C to +80°C.
Q: What vehicles can Dometic rooflights be fitted to?
Motorhomes and campervans, caravans and panel-van conversions. They come in many versions and Dometic describes them as dependable, simple to fit and long-lasting.
Q: What roof thickness do Dometic rooflights suit?
It varies by model - Dometic lists every rooflight's dimensions and specifications on its website. Before fitting one, measure your roof's thickness and check whether the cut-out (the gap between the inner and outer roof skins) needs reinforcing; if in doubt, ask the vehicle's manufacturer.
Q: How can I tell which Dometic rooflight I have, so I can replace it?
Look for the information printed on the pane before ordering. The PNC/SKU number and code identify when it was made and which spare parts it takes, and the letters and numbers along the bottom identify the glazing. Rooflights made after February 2016 also carry a label on the inside (on the Midi Heki, for example) - though there's no label on a Mini Heki.
Q: How much does a Dometic rooflight weigh?
Between about 2.9 kg and 22 kg, depending on the model.
Q: What size roof opening does each Dometic rooflight need?
400 x 400 mm for the Mini Heki S, Mini Heki Plus and AirQuad; 700 x 500 mm for the Midi Heki; and 960 x 655 mm for the Heki 4 Plus, Heki 3 Plus, Heki 2 and Heki 1.
Q: Why is there condensation between the panes of my rooflight?
Acrylic is an organic material that absorbs tiny amounts of water, so moisture can work its way through the acrylic, making the air wetter in the gap between the two layers of double glazing. When it gets colder outside, the air in that gap cools and the excess moisture condenses on the coldest surface - the inside face of the outer pane.
It isn't a fault. To clear it, ventilate the vehicle to bring the humidity down (good air circulation helps), or raise the temperature inside, since warmer air holds more moisture - then give it time to disappear.
Q: What causes scratches on my rooflight?
Usually dust or grit blown against it, whether you're driving or parked. Brushing against tree branches on the road, or washing it with an abrasive sponge, can scratch it too.
Q: What causes cracks in my rooflight?
Cracks in acrylic are usually caused by 'stress corrosion' - chemical attack on the material while it's also under tension. Over the years, changes in temperature and repeated wetting and drying create slight stresses in the surface; on their own these are harmless, provided the pane is cleaned and cared for properly. But cleaning products that aren't suitable for acrylic attack the stressed surface and can eventually destroy the pane.
So never use glass cleaner, general-purpose cleaner, abrasives, washing-up liquid or anything containing alcohol.
Q: What should I clean my caravan or motorhome windows and rooflights with?
Only a cleaner made for acrylic glass. Never use harsh products - glass cleaner, general-purpose cleaner, abrasives, washing-up liquid - or anything containing alcohol.
Q: Where can I get spare parts for a roof hatch, service hatch or sliding window?
Your caravan or motorhome dealer can order them for you - Dometic's website has a dealer locator to find one.