Autofill issues & Reverse engineering the KIB V-Bus Protocol

[dxg0001]

We ended up at an RV park with really bad water so I decided to install a full house Reverse Osmosis system in my 2019 Ventana. There are several posts where people describe their installation but basically, the RO system generates water which fills the fresh water tank. All water use is done via the fresh water tank. Rather than drilling through the tank to install a float switch to control the filling of the tank, I chose to simply use the autofill feature I already have. I rerouted incoming city water to the autofill solenoid and from there to the RO system. Inside the coach on the KIB control panel a simply turn on Autofill and it will start filling when it is/gets below a certain level and stop when it gets full.

Or so I thought. After draining my tank and started the autofill to let it fill up for the first time, it stopped after about 15 minutes. I restarted and same thing happend. I ended up overriding the system so it kept filling overnight. I'm still only at 55% this morning but now I'm looking for a solution to this.

I read several posts in this forum where people reverse engineered the KIB protocol to control their black/gray tank valves, etc.

My idea is to hook into the KIB CAN-BUS or V-BUS and monitor the water level and write my own algorithm to control the autofill valve.

I was wondering if anybody who has already deciphered the KIB protocol would share that with me to safe me same time.

Many thanks,
Dan

[Bobby Dowdle]

We normally tie into the filter on the system and utilize all the existing coach electronics1 and plumbing. Can you provide a drawing of how you connected to the auto fill valve. It might just be easier to install float then try to reengineer the KIB board.

[truk4u]

The last RO system I had would do 50 gallons per day as long as the sun, moon and stars lined up and that was with a separate tank. You’re likely looking at days to fill your coach fresh water tank.

[dxg0001]

Originally Posted by Bobby Dowdle

We normally tie into the filter on the system and utilize all the existing coach electronics1 and plumbing. Can you provide a drawing of how you connected to the auto fill valve. It might just be easier to install float then try to reengineer the KIB board.

Agreed. I'm trying to use what's already in the coach. I hate having to drill into the water tank even though that may be the only solution if I can't decipher the protocol.

Here is a simplified diagram. I'm using the existing house filter as the stage 1 filter. From there I run a line to the autofill valve which continues to the stage 2 and 3 and the RO membranes.

All very simple if the KIB system was working.

[Winepress]

Save yourself some time and frustration by adding a float switch. It doesn’t take long to install and leaves the auto fill OEM if you need to bypass the RO system. I put in two, low level and full level. When we have a travel day I set it to low level which allows us to carry less water. Once we are set up I will switch to full. We make 100 gal per day with a dual membrane set up from the RV water filter store.

[dxg0001]

Originally Posted by truk4u

The last RO system I had would do 50 gallons per day as long as the sun, moon and stars lined up and that was with a separate tank. You’re likely looking at days to fill your coach fresh water tank.

Yes, I was worried about not having enough capacity and running out of water, especially since I decided not to install a boost pump (yet) to keep it simple. The water pressure here is only around 45 PSI which is quite low compared to most parks we have been to. However, we started out with 70% full yesterday and had a very heavy water day (4 x laundry, dish washer, showers, washing the dog, etc.) and never dropped below 30%. I'm using 2 x 200 g/day membranes from RV Water Filter Store and I'm prepared to add a boost pump which would probably double the output but for now it looks like I'm ok.

My main issue still is that the KIB autofill only seems to stay on for 15 minutes. If I could only fix that I'd be in good shape.

[GUS2000]

Check your water pressure after the RO system, if you have only 45PSI going in, chances are you have <40psi coming out of it. Not sure why, but if the water pressure is that low, the auto fill function will not stay ON until its full, it will shut off... I noticed that when I added a filter to our incoming and the pressure was 45PSI out of the filter and it would do exactly what you are describing.. when I adjusted the pressure to be 55PSI out of the filter, it has worked as designed ever since.