Grey waste sensor (1 Viewer)

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Nov 6, 2011
438
656
Worthing
Funster No
18,785
MH
Knaus Sky Ti
Exp
2001 to date
We have a Knaus 700 TI (2013). On the last trip, the grey waste sensor decided to play silly games. In the space of 24 hours, when we had just emptied it, it showed 100%, 80%, 40% etc., etc! Now I could just ignore it, but if Ive got it, I want it to work properly. Unlike the fresh water tank, I can see no way of accessing inside the tank to check for gunge build up. Anyone had experience of this, especially on a Knaus?

Keith
 
Nov 6, 2012
196
279
Guildford
Funster No
23,594
MH
3litre Bessacarr 765
Exp
Restarted 2012
I have the same problem. I assumed the sensor contacts were contaminated as the M/h is 9 years old. There is a large cap on the base of the grey tank which I unscrewed easily. The small amount of residue waste was surprisingly cleanish and even feeling around inside the base of the tank was clean. The downside was after all my effort I couldn’t locate the sensor so back to guessing!!! The joys of motorhoming.
 
Jan 22, 2012
1,491
2,306
Wigan
Funster No
19,541
MH
Knaus Sun TI 2012
Exp
2010
We also have a Knaus Sun TI 700LX the sensor on the waste has always been totally inaccurate. We have ignored it for last 5years , Its not an issue for us as we tend to keep a large bucket outside with the waste continually draining into it, that way we avoid the smells of long standing waste water.

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grasscutter

LIFE MEMBER
Oct 11, 2009
2,538
9,638
East Wittering. West Sussex.
Funster No
8,848
MH
Hymer Exsis i588
Exp
Started in 1980
The sensor on our Hobby has developed a mind of its own on this trip.
We get a red flashing full waste light. No rhyme or reason to when it starts or goes off.
Will get under van on our return and disconnect it.
 
Nov 4, 2011
6,188
42,271
Uk
Funster No
18,763
MH
A class
Exp
2001
My sensor plays up occasionally, remove it and find the prongs covered in muck.
 
May 24, 2014
654
2,564
North Devon
Funster No
31,634
MH
Autosleeper Kingham
Exp
Since 2013
You'll find many threads on here over the years on any number of makes of Motorhomes as well as some solutions albeit short term ie swill the tank with lots of coke cola!
I have disconnected the warning buzzer and just empty the tank as regularly as possible (in proper sites l may add).
 
Apr 19, 2018
57
148
Funster No
53,450
Hello Pikeman, I've also got a Knaus and, not only does it give wrong readings, it also beeps every 15 seconds because it thinks it's full.
Did you ever find out how to get to the probe/sensor?
 
OP
OP
Pikeman
Nov 6, 2011
438
656
Worthing
Funster No
18,785
MH
Knaus Sky Ti
Exp
2001 to date
Hi Ken,
No, I still haven't found out how to access the probe. I tried back flushing the tank, whilst it had 6 litres of coke in it, it went from 90% to 80% when empty, so basically no joy. I even joined the Knaus owners club, only to find that they don't have a forum where you can ask other owners - bloody useless!!

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Apr 19, 2018
57
148
Funster No
53,450
Thanks for the reply.
On the plus side, at least you haven't got the beeping every 15 seconds.
I'll do my best to find the probe and if I manage it will get back to you.
 

138go

Free Member
Feb 26, 2016
3,276
14,614
Funster No
41,781
MH
Carthago 138
Exp
Since 2001
If it has a CBE Control Panel you can turn the bleep off. Our Control Panel bleeps when the water is getting near empty so I switch it off if we are on the way home. Otherwise I panic and try and find a tap (y);)
 
Apr 19, 2018
57
148
Funster No
53,450
If I could turn off the alarm it would solve all my problems - I don't think it's a CBE panel, though.
319148
 
Sep 11, 2022
1
0
Funster No
91,256
MH
Knaus
we have this panel in our Sky TI 650 and it has for a while not switched the pump once we have arrived on site and it takes a lot of pressing on the water symbol before it comes on which we need to sort but last weekend the alarm (silenced alarm) showed red flashing and the tank was flashing, hardly any water is waste tank and still is was flashing red? unsure of how to rectify this, also the waste tank when emptied stinks fouls , bad eggs etc horrid, how do we rectify this, maybe buy a new control panel?
 
Mar 12, 2021
459
649
Renfrew Scotland
Funster No
79,716
MH
kontiki sport
Exp
20 years tugging .5 years MOH.
Got the same problem 2 years old swift kontiki, I very seldom check levels anymore just go with instinct you tend to get a feel for it.
Or you could fit Mopeka Bluetooth sensors I’ve got them on gas bottles so accurate.

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Jul 31, 2014
1,954
3,280
West Yorkshire
Funster No
32,620
MH
EuraMobil Activa 820HS
Exp
2007
Do you have an access cap/opening to your waste tank?
Ours is located beneath the floor with a trap door above. There’s a giant cap that can be unscrewed for you to see into the tank.
I occasionally squirt the hose into her and around the inside of the tank to clean off any residue build up.
I’ve found that this also cleans the sensor which helps give a better contents reading/more accurate
 
Apr 27, 2008
11,932
14,259
Eastbourne East Sussex
Funster No
2,327
MH
Hymer low profile
Exp
Since 1972
My current motorhome waste tank reads empty when it's empty and 25% when it isn't. At least there's no bleeps or buzzes.
As before I just assume if the fresh needs filling the waste probably needs emptying. Of course the fresh water gauge isn't particularly accurate either but at least full and empty are correct.
 

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