Vaillant VC430 Boiler Controller

This discussion started here Vaillant VC430 Boiler Controller | Archived Forum

I want to know how people have gotten on with getting their boiler to become smarter. I have all the tools needed to read and write to the eBus. But I do not have the Vaillant controllers, so I do not know what messages are sent between the controller and the boiler.

What I am looking to do is to use the boilers ability to deal with a Hot Water demand, separately from a Central Heating demand. The boiler is able to do this but only when used via Vaillant’s own controllers. The idea it to run the Central Heating at a lower flow temperature, but the moment there is Hot Water Demand to run the boiler at the higher temperature until the DHW demand is satisfied.

Could anyone help?

I have the VRC430 installed at home along with the boiler but I use it with a hot water tank - are you using it for instant hot water like a combi-boiler?

I am also using a Vaillant uniStor too. I have an Open Vented Boiler ecoTec 438. So I would be very interested in knowing what eBus commands the VRC430 issues to the boiler when there is Hot Water demand. How does the boiler know it’s meant to be using the HW limiter as opposed to the CH limiter.

There is an additional control unit in my setup which controls the 2 way valve directing the hot flow from the radiators to the hot water tank.

This controller also connects to the eBus circuit - do you have this controller?

I have absolutely no eBus devices except for my eBus interface that allows me to send and receive eBus commands. Actually that is not entirely correct. I use a VR33 which is basically an OpenTherm to eBus converter. But my boiler and the valves are controlled by Evohome. What I need to see are the messages that are sent between the controller and the boiler that tells the boiler that its either working in the HW or CH mode and thus uses the relevant max temperatures as set on the knobs in the front. Currently my boiler only uses the CH knob for both HW and CH. Which is fine, except that the CH knob needs to be set high enough to satisfy the HW heat demand too.

I wonder if Roger Munford is on the new forum or anyone has his contact details. Because he seems to have done work in the area I am interested in.

I have a VR66 module controller, plus the “keypad” VRC430 module which links to it.

Are you doing any eBUS monitoring? Do you have any way of capturing the
messages that are flowing between the various eBUS devices?

Sorry no, I’ve never looked at it in much detail

Bruce,
the admin contacted me about the new arrangements and asked if I would like to continue.

I have discovered from various websites and verified on my own vc430 that they work. I have a raspberry pi which monitors the ebus and enables me to programme the vc430 remotely. I have left it at that for a couple of years but I want to add a bit more intelligence to it so it so that the boiler wastes less gas. I only change values in the vc430 not in the boiler itself.

I am more than happy to share anything I have learned if you are doing anything similar.

Regards

Roger

Command Reply
20 31 09 FF 15 B5 09 03 0D 80 00 82 02 7E 01 C6 //Room Temp 017E = 382/16 = 23.875
20 31 09 FF 15 B5 09 03 0D 62 00 88 03 81 01 00 40 //Outside Temperature
20 31 09 FF 15 B5 09 03 0D 5F 00 9D 01 02 99 //Weekday Monday = 0
20 31 09 FF 15 B5 09 03 0D 60 00 25 03 33 2F 10 D4 //Time
20 31 09 FF 15 B5 09 03 0D 61 00 BE 03 10 07 0E E0 //Date DMY
20 31 09 FF 15 B5 09 03 0D 0B 00 A6 01 00 9B //Holiday Function Active No
20 31 09 FF 15 B5 09 03 0D 2F 00 03 01 01 9A //HC1 OPM Mode 1 = Manual, 2 = auto ,0 = off
20 31 09 FF 15 B5 09 03 0D 30 00 DF 01 1E 85 //hc1 night set temp half degs 15
20 31 09 FF 15 B5 09 03 0D 31 00 44 02 D2 00 70 //HC1 Heat curve
20 31 09 FF 15 B5 09 03 0D 32 00 72 01 22 B9 //hc1 manual roomsetpoint temp in half degree
20 31 09 FF 15 B5 09 03 0D 3C 00 07 01 24 BF //hc1 quick veto temp in half degrees 18
20 31 09 FF 15 B5 09 03 0D 3D 00 9C 01 00 9B //hc1 quick veto active No
20 31 09 FF 15 B5 09 03 0D 3F 00 31 0B 48 45 41 54 20 20 20 20 20 20 00 20 //HC1 Circuit name
20 31 09 FF 15 B5 09 03 0D 3F 08 39 0B 68 65 32 20 20 20 20 20 20 20 00 0A //HC2 Circuit Name
20 31 09 FF 15 B5 09 03 0D 3F 78 49 0B 43 79 6C 69 6E 64 65 72 20 20 00 8C //DHW Name
20 31 09 FF 15 B5 09 03 0D 40 00 41 01 09 92 //holiday room set temperature half degrees 4.5
20 31 09 FF 15 B5 09 03 0D 11 00 20 03 01 01 07 68 //Holiday Start
20 31 09 FF 15 B5 09 03 0D 12 00 16 03 01 01 07 68 //Holiday End
20 31 09 FF 15 B5 09 03 0D 42 00 EC 01 02 99 // DHWOPMMode
20 31 09 FF 15 B5 09 03 0D 44 00 80 01 64 FF //DHW Desired Temp half degrees
20 31 09 FF 15 B5 09 03 0D 45 00 1B 01 64 //DHW Quick Veto Temp half degrees
20 31 09 FF 15 B5 09 03 0D 43 00 77 01 00 //DHW QuickVetoAction
20 31 09 FF 15 B5 09 03 0D 4C 00 99 01 78 //DHW Manual OPs setpoint half degs 60
20 31 09 FF 15 B5 09 03 0D 53 00 45 01 01 //Summer WinterAdjust ON
20 31 09 FF 15 B5 09 03 0D 9E 00 C5 01 54 // Displayed DHW Tank Temperature half degs 44
20 31 09 FF 15 B5 09 03 0D 96 00 DC 01 2C // Displayed HK1 Room Setpoint half degs 22

SET COMMANDS
20 31 0A FF 15 B5 09 04 0E 32 00 TT CC No reply perhaps 00 00 00 3 ACKs // set HC1 Manual OPR set point TT in half degrees
20 31 0A FF 15 B5 09 04 0E 2F 00 01 4E No reply // set HC1 Operating mode 1 = Manual
20 31 0A FF 15 B5 09 04 0E 30 00 20 46 No reply // set Night Set temperatue 20 → 16 degrees

looks like OD means read, OE means write. 32 = Manual OPR, 2f = Mode etc

Get Commands
GET Switching times
20 31 08 FF 15 B5 15 02 DD 00 CC where DD is day, Monday = 00, Tuesday 01 etc CC is CRC Day number different from below
Reply
08 00 START1 STOP1 START2 STOP2 START3 STOP3 02 CC Times in 10 mins ie 0x32 = 50 x 10 = 500 mins = 8:20
GET Temperature
20 31 08 FF 15 B5 04 02 19 DD CC where DD is day, Monday = 01, Tuesday 02 etc (diff from above)
Reply
04 DD T1 T2 T3 CC where DD is day from get command T is Temperatur in half degrees ie 24 = 36 x 0.5 = 18 deg

Thanks for coming back with this.
I actually landed up buying a VC430 myself and was able to control it completely using ebusd and the associated configuration files for the VC430. However the sad part was that I couldn’t use it. The Vaillant eBUS doesn’t allow 2 thermostat devices to reside on the bus. So the moment I connected the VC430 to the eBUS, my normal thermostat stopped talking on the bus because of the eBus device hierarchy.
ebusd is a great bit of software and most of the hard work has already been done for many of the devices. I had a VR33 so had some fun figuring out the data structures but that too wasn’t half as bad as I imagined it to be.

Are you sure about this? When I last looked (a few years ago) they sold seperate room thermostats that worked alongside the main VRC430 unit - you do need to ensure that the unit addresses are different when installing (from memory!)

Just to add, reading the instructions (!) it seems you have to enable the multi-room mode in the VR66/VR65 controller not the VRC430 unit itself.

That’s right. Only when the VR66 is detected on the bus, does the VRC430 display other configuration pages that allow it to be used in a dual zone environment where you have another thermostat in the other zone besides the VRC430 in one of them.