Why is RV levelling necessary?
An absorption refrigerator cycle is designed for the horizontal position; on a slope efficiency drops. Draining, doors and sleep also depend on levelling.
Levelling is not only a comfort matter: the cooling cycle of an absorption refrigerator is designed for the horizontal position, on a slope its efficiency drops and in long-term use a risk of failure arises. Alongside that, doors open and close by themselves, shower and sink water does not drain fully, and at a slope of a few degrees sleep comfort is noticeably spoilt. Levelling removes all of these problems in a single operation.
Systems affected by slope
- Refrigerator: The cooling cycle of absorption refrigerators is designed for the horizontal position; on a slope efficiency drops and in long-term use a risk of failure arises. The accepted slope allowance varies by model and is stated in the manual; that is why the tilt tolerance is looked up per appliance.
- Water system: The sink and shower drains do not empty fully on a slope. The water left behind smells and carries a risk of freezing in winter; the relation between draining and slope is under a separate heading.
- Doors and drawers: On a slope they open and close by themselves; hinges and lock tongues tire over time.
- Sleep comfort: Even a slope of a few degrees is noticeable; a slope in the head-to-foot direction is particularly uncomfortable.
- Hob and oven: The liquid in a pan gathers to one side and oil runs to one side; when the slope is combined with a hob guard, a risk of tipping over arises.
From symptom to cause
| Symptom | Probable cause | Check |
|---|---|---|
| Refrigerator does not cool, its vent is not blocked | Slope lengthways or crossways | Level the vehicle and wait a few hours |
| Water pools in the shower | Slope runs the wrong way towards the drain outlet | Correct the crossways slope |
| Cupboard door opens by itself | Lengthways slope | Make a front-rear correction |
| Feeling of sliding down at night | Slope in the head-to-foot direction | Note the direction of the bed and correct it |
Why levelling by eye is not enough
The human eye misjudges small slopes by looking at indoor references; ceiling and cupboard lines are open to optical illusion. The suspension of the vehicle misleads as well: a full water tank and the people inside tilt the vehicle to one side, and a vehicle that looks level in the morning may be tilted in the evening. A spirit level gives the right result, but reading the two axes separately and making the correction by hand with blocks takes time; while you correct one axis the other often shifts. KTS200 does this job with a levelling precision of 0.025° and by evaluating the two axes together; what that value means in the field is explained under a separate heading.
Problems levelling does not solve
- Rocking. The movement felt while walking about inside is not a levelling matter; the difference between levelling and stabilisation is a separate subject.
- Parking safety. The legs do not take the place of the parking brake and the chocks; do not lift all the wheels clear of the ground.
- Bad ground. On very rough ground the parking spot has to be chosen first; leg stroke is not unlimited.
- Faulty appliance. Levelling does not put right a refrigerator that is already broken; on an appliance run on a slope for a long time the damage may be permanent.
- Wrong reference. If the sensor is mounted on a sloping surface the system works correctly by its own reckoning but the vehicle stands tilted; without a tare (zeroing) at first installation the result is not reliable.
In practice, do this: when choosing where to park, look at the slope of the ground, take the vehicle to the flattest spot you can, then do the levelling, and start the refrigerator only after the vehicle has been levelled. On long stays the ground can settle during the day; checking the slope once more the next morning is a good habit.
The full topic: RV automatic levelling guide