Pros & Cons of Vaillant VRC700 controller

[Harry Bloomfield]

Ive been considering a VRC700f, ive got an older ecotec 418 and VR66 but using legacy timer and a timed roomstat.
Based on what you have said if I want the weather comp stuff and work as close to before as possible then get a VRC430/VR81 instead.

VRV700F has an optional wireless outdoor sensor, which it uses for weather compensation.

 

[rbranco]

Another annoyance is that some data, the time and date is stored in the 700F, some in the boiler interface unit. The manual hint that it can get its time and date from radio time - it cannot in the UK version. If the boiler is powered down for a service, time date and on/off times need to be reset.

Looks like there are two versions of the wired sensor.
The VRC693 is just a simple thermistor, but the VRC9535 seems to have an extra wire for DCF which is the time signal from Germany but can be received in much of the UK, but for some reason its not sold here that I can see. If you have the 693 and can replace it with 9535 then you will probably get the time running.
The VR21 on some places is sold as VR21(DCF) so I would assume it may have it already, not sure about VR20 the older one.

 

[Milleniumaire]

VRV700F has an optional wireless outdoor sensor, which it uses for weather compensation.

I confess I'm not a big fan of wireless and will always go for wired when possible or even if only 80% possible, usually meaning lots of extra work The problems with wireless are connectivity and using batteries for power.

Don't get me wrong, I use WIFI products all the time, but only when they are designed to be portable. Anything that's fixed should be wired in my opinion. I do accept that it isn't always possible to run wires and in those situations wireless is a good option.

So, my outdoor sensor is wired and all my thermostats are wired. My 18 month bathroom refurbishment project involved me taking up a lot of floor boards to get new pipes between the boiler at one end of the house and on the ground floor, to the bathroom at the other end of the house on the first floor. I took the opportunity to lay some cables, including one for the new bathroom thermostat.

Having said that, the new Mira Platinum Dual digital shower I installed does use a wireless controller. I would have preferred it if it didn't, but they don't give the option!

 

[Harry Bloomfield]

I confess I'm not a big fan of wireless and will always go for wired when possible or even if only 80% possible, usually meaning lots of extra work The problems with wireless are connectivity and using batteries for power.

The sensor, most of the time works fine, in the hall, close to the kitchen door, but when the cooking begins it tends to see a false temperature due to the oven. Then I simply unclip it and move it to the living room. It has never had an issue the signal, or signal from the outdoor sensor.

The 4x batteries seem to last around 8 months.

Another slight annoyance if I'm in a hurry, is if the temperature is manually changed temporarily. It then sits on that screen far too long, leaving you unable to change or check anything else, only the knob and OK button are live, until the screen times out.

 

[rbranco]

The part numbers haven't changed so will be the correct part number, but probably not the newer version. It needs the /2 label as shown in the sensohome picture you've posted. I'm not 100% sure there in circulation yet. It may work but its not the one its designed for so could have compatability issues.

Just for info, ive checked with Vaillant, they say the sensoCOMFORT VR720f is compatible with original VR66 as well but only as monozone, they checked with tech.
They are not sure themselves at the current time how the enduser can tell the difference or what realworld differences there are between VR66 & VR66/2, but regardless the VRC will be compatible with older one.

 

[Harry Bloomfield]

Just for info, ive checked with Vaillant, they say the sensoCOMFORT VR720f is compatible with original VR66 as well but only as monozone, they checked with tech.
They are not sure themselves at the current time how the enduser can tell the difference or what realworld differences there are between VR66 & VR66/2, but regardless the VRC will be compatible with older one.

Have a look on the PCB, it might be marked. Possibly it runs revised firmware?

 

[rbranco]

Have a look on the PCB, it might be marked. Possibly it runs revised firmware?

Maybe for new features in future or better compatibility with something but even they do not know.
I always wondered why the VR66 did not support WC on multi-zone, maybe they add ability for this, not sure who knows, that does not bother me as im monozone anyway.

 

[Harry Bloomfield]

Maybe for new features in future or better compatibility with something but even they do not know.

No surprise there, Vaillant's UK tech department didn't seem to understand much when I spoke to them trying to get to the bottom of the little niggles in my system

 

[Milleniumaire]

Does anyone have any idea about the numbering system Vaillant use for wiring centres?

My original wiring centre (10 years ago) was the VR 65, which supported one heating zone and DHW via a cylinder.
I upgraded to the VR 61 6 years ago, which added a second heating zone.
I've just upgraded to the VR 71, which supports three heating zones and DHW.
And I'm aware of the VR 66, which I believe supports 2 heating zones, like the VR 61.

So, what's with the 65 and 66 versus 61 and 71 numbers?

 

[rbranco]

Does anyone have any idea about the numbering system Vaillant use for wiring centres?

My original wiring centre (10 years ago) was the VR 65, which supported one heating zone and DHW via a cylinder.
I upgraded to the VR 61 6 years ago, which added a second heating zone.
I've just upgraded to the VR 71, which supports three heating zones and DHW.
And I'm aware of the VR 66, which I believe supports 2 heating zones, like the VR 61.

So, what's with the 65 and 66 versus 61 and 71 numbers?

VR65/66 - this allows for HW priority and NTC/CylStat connections for HW tank on regular ecotec boilers which do not have built in diverter valve, only supports WC when in monozone mode, in multizone it will not support WC as it does not have ability to mix flow temps etc (VR65 monozone only)
VR61 - this is a mixer module, you would normally use this on a system boiler to give multizone with individual zone temps (there is 2nd NTC for the additional zone) while maintaining WC but it does not control HW tank as the system boiler would normally do this for you, Im not sure if to give mixing and HW tank support on regular boiler if you need both of these.
VR70/71 - This seems to be a unit that has all the funcctionaly of 61/66 etc.

Oh its so confusing, they do not have a single page that has all the different modules that I can find.

 

[Milleniumaire]

No surprise there, Vaillant's UK tech department didn't seem to understand much when I spoke to them trying to get to the bottom of the little niggles in my system

Recently, their support has been less than good, with conflicting answers given by different people. I'm still waiting for responses to emails that were sent 2 weeks ago, whereas I've already had a response to an email I sent last week. I suspect they are being affected by Covid and home working, but that doesn't excuse them from being disorganised or giving incorrect information!
I've had mixed experiences from Vaillant tech support, but they seem to be getting worse.

Oh its so confusing, they do not have a single page that has all the different modules that I can find.

Thanks, that makes it a little clearer, but I do think they have a problem with the way in which they assign names to their products and also with the information (or lack of) that is available via their website.

 

[rbranco]

I was able to speak with vaillant advanced support today.

I asked what the difference is with the VR66/2 and was informed it was a fix to allow running multiple zones a little better with newer VRC controllers but they have had issues with it so just use it like a monozone system, very odd.

Right I have confirmed that a VRC720f does work with the older ecotec 418 and the VR66, bit of a faf as their paperwork does not describe any setup for openvent boilers with VR66 so even the tech person was saying I needed to setup the controller in a certain way then it did not work and came up with error on controller. Apparently when you fit a VR66, to it appears as if the boiler is now a system boiler, its essentially invisible to VRC etc but you can not setup the VRC720f as if you have a system boiler else it goes all wrong, you just leave the system diagram set to 1 and the VR66 set in legacy mode, it will not work in non-legacy mode nor multiple zone mode. But that is ok for me.

Its a nice controller, not very strong signal though but could be due to the solid walls in my house.