Hello there - long time stalker and found this forum to be a very useful resource - first post so please be gentle
Some may find this interesting
Just moved to a large grade 2 property which has a rather big heating installation with 2 boilers and a DHW tank that is taller than me. It appeared to work for the first week we were here but then seemed to lose comms with the boilers and get confused, power cycling the boilers seemed to bring them back to life again (it ran as though it thought they were there but they did nothing) - I noted the settings and did a circuit digram (also corrected some distressed wiring) and then factory reset the controller - all worked again for a few weeks until the same happened again (power cycled the boilers are all good again).
Here is a the system - all Vaillant
- VRC700 controller
- VR70 wiring board
- ecotec plus 728 (appears to be triggered by DHW)
- ecotec plus 730 (appears to be triggered by CH)
- VRF 693 outside temp sensor wired to the 728
- There is also a larger Grunfoss pump which is triggered whenever the DHW/CH valve opens
- CH on on the VR70 R2 output has zone valve to rads (only one zone for entire house / 15 rads)
- DHW is on the VR70 R3 output has zone valve to DHW tank
- there is a DHW + 2 x temp sensors installed on S1, S5 & S6
- Boiler 728 is daisy chained to VR70 eBus
- Boiler 730 is daisy chained to Boiler 728 eBus
I added a VR 930f gateway so the whole lot works on myVaillant app now
- myValliant apps only see the 728 DHW boiler and not the 730 (same as the VRC700 which only sees 1 heat generator)
- occasionally the VRF 693 outside temp sensor throws an error and then comes back (this may be related)
- I noted inside the 730 boiler (which is more modern there is a bus id wheel set to 1)
- I have Zone 1 disabled as it is not used
- I have Zone 2 connected to the VR700 for the temp of the CH
So to summarise the issues
- when it all works it works great
- occasionally there is a hiccup and the 2 x boilers seem to drop or lockup on the eBus (power cycling both seems to resolve) - the system tries to run the main pump with the valves open but the boilers do not fire up when they should - it ends up pulling the stored heat in the DHW tank into the CH system so eventually it all goes cold)
- on the VRC700 and myVaillant app only the 1st boiler shows up on the device list even though both work (728 DHW & 730 CH)
- I replaced the VR70 but no change in behaviour
- It was like this when we moved in so I do not think it was ever configured 100% and the previous owner didn't realise (do not know who installed or configured it)
Is there a white paper for the correct setup and configuration of 2 boilers on a Vaillant eBus system? do I need to adjust the eBus ID for the second boiler? I am puzzled as to how this is working at all - when it does work the system uses each boiler for a specific purpose and yet I see no configuration for this.
Any help or advice would be great, also if there is a Vaillant specialist in the Crawley area I am happy to pay for an inspection/tune up
Some may find this interesting
Just moved to a large grade 2 property which has a rather big heating installation with 2 boilers and a DHW tank that is taller than me. It appeared to work for the first week we were here but then seemed to lose comms with the boilers and get confused, power cycling the boilers seemed to bring them back to life again (it ran as though it thought they were there but they did nothing) - I noted the settings and did a circuit digram (also corrected some distressed wiring) and then factory reset the controller - all worked again for a few weeks until the same happened again (power cycled the boilers are all good again).
Here is a the system - all Vaillant
- VRC700 controller
- VR70 wiring board
- ecotec plus 728 (appears to be triggered by DHW)
- ecotec plus 730 (appears to be triggered by CH)
- VRF 693 outside temp sensor wired to the 728
- There is also a larger Grunfoss pump which is triggered whenever the DHW/CH valve opens
- CH on on the VR70 R2 output has zone valve to rads (only one zone for entire house / 15 rads)
- DHW is on the VR70 R3 output has zone valve to DHW tank
- there is a DHW + 2 x temp sensors installed on S1, S5 & S6
- Boiler 728 is daisy chained to VR70 eBus
- Boiler 730 is daisy chained to Boiler 728 eBus
I added a VR 930f gateway so the whole lot works on myVaillant app now
- myValliant apps only see the 728 DHW boiler and not the 730 (same as the VRC700 which only sees 1 heat generator)
- occasionally the VRF 693 outside temp sensor throws an error and then comes back (this may be related)
- I noted inside the 730 boiler (which is more modern there is a bus id wheel set to 1)
- I have Zone 1 disabled as it is not used
- I have Zone 2 connected to the VR700 for the temp of the CH
So to summarise the issues
- when it all works it works great
- occasionally there is a hiccup and the 2 x boilers seem to drop or lockup on the eBus (power cycling both seems to resolve) - the system tries to run the main pump with the valves open but the boilers do not fire up when they should - it ends up pulling the stored heat in the DHW tank into the CH system so eventually it all goes cold)
- on the VRC700 and myVaillant app only the 1st boiler shows up on the device list even though both work (728 DHW & 730 CH)
- I replaced the VR70 but no change in behaviour
- It was like this when we moved in so I do not think it was ever configured 100% and the previous owner didn't realise (do not know who installed or configured it)
Is there a white paper for the correct setup and configuration of 2 boilers on a Vaillant eBus system? do I need to adjust the eBus ID for the second boiler? I am puzzled as to how this is working at all - when it does work the system uses each boiler for a specific purpose and yet I see no configuration for this.
Any help or advice would be great, also if there is a Vaillant specialist in the Crawley area I am happy to pay for an inspection/tune up