Vaillant VRT 340f room stat - error message

Hi all,
I have a Vaillant VRT 340f wireless programmable room stat - the early version without the dial. I've just changed the batteries (2xAAA) - something I've done several times before - and now the display just shows 'Err'. I've tried leaving the batteries out for a few minutes and then reinstalling them, but to no avail. Does anyone have experience of these devices?

Normally means communication error.

Normally a battery issue is a BATT error code.

Check that the base receiver has power and is operating.

Fit the remote with new quality (Duracell Plus type) batteries. Place the remote unit within a 2m clear line of sight of the base receiver.

If you still get the RF ERR code, you need to clear and rebind the units.

In my experience, they rarely fail, a rebind normally cures the issue.

Thanks for the rapid response! I’m slightly mystified that the unit shows ‘Err’ alone without any qualifier such as ‘RF’, but hey-ho. Rebinding sounds like a good idea, but how do I do that?

Neil Sutherland said:

Thanks for the rapid response! I’m slightly mystified that the unit shows ‘Err’ alone without any qualifier such as ‘RF’, but hey-ho. Rebinding sounds like a good idea, but how do I do that?

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Is it wireless? Cannot remember if the old one is wired?

Yes, it’s wireless. Working fine until the battery change. After the change the receiver on the boiler was showing a red light, but that cleared when I pressed the button and it now shows green as usual. Next I took the new batteries out of the room stat for a few minutes, but when I put them back I got the ‘Err’ message again.

Have you tried taking the batteries out and putting them back in again😛😛😛😛😛😀😀😀

Harvest Fields said:

Have you tried taking the batteries out and putting them back in again😛😛😛😛😛😀😀😀

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Is that the same as any IT boffins response “turn it off and on again”? 😀😀😀

Neil

Reestablishing the RF link between the units is set out in the owners manual.

The 340f is a little odd - the two batteries are not connected. One feeds the LCD. display and the other the RF transmitter.

Check to ensure that both batteries are inserted correctly, that there has been not leakage from the old batteries and that you have at least 1.5v across each set of terminals.

Don’t be misled into thinking that because the display is functioning, both batteries are installed correctly with enough power

Still no luck, so I called the Vaillant helpline today. The response was that there's no fix, and the unit will have to be replaced. Great. So now I'm on the lookout for a compatible unit; ideally one that will use the existing receiver but otherwise one that I can plug into the boiler connections. I've asked the question of Vaillant by web form, but if anyone knows what might work I'd love to hear from you. I imagine the later VRT 340f should work, but the only one on eBay is £350. There has to be a cheaper option!

Honeywell CM927 - but you will need a reasonable capability to fit it

Brambles said:

Honeywell CM927 - but you will need a reasonable capability to fit it

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Nope. He needs to be gas safe registered to fit it.

You can only determine that when you know the boiler type - he has not even clarified that it fitted to. Valliant boiler

Brambles said:

You can only determine that when you know the boiler type - he has not even clarified that it fitted to. Valliant boiler

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You try and justify it however you want mate.😛😛

He asked for help, I gave him an answer - I indicated that it was tricky to fit. On reflection I should have expanded that with a warning that if the connection to the boiler was not within the area covered by GS(IU) Regulations you would need to be Gas Safe.

The controller he is seeking to replace was packaged with a number of boilers other than Valliant - in the UK Valliant used it extensively with the EcoVit range which is oil fired. Vokera also package this control on a number of large social housing projects.

Perhaps we just need to wait for the OP to tell us the boiler type and where the receiver is mounted. Then we can give him / her clear unambiguous advice.

Thanks, chaps. Sorry to spark another debate about Gas Safe registration! The boiler is a Vaillant Turbomax Plus 837e - I think the wireless receiver is probably a plug-in module but I’ll take your advice about that.

Neil Sutherland said:

Thanks, chaps. Sorry to spark another debate about Gas Safe registration! The boiler is a Vaillant Turbomax Plus 837e - I think the wireless receiver is probably a plug-in module but I’ll take your advice about that.

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Should just clip in/out to be fair.

I've had a reply from Vaillant, which says the only solution is to fit a VRT350f with a VR39 interface; to quote: "The VR39 is fitted into the BMU box on the boiler and converts the outputs from terminals 7, 8 and 9 into eBus that the VRT350f can read". I've looked online but haven't yet found a VR39 from a UK supplier - and it seems quite pricey at around €100. Anyone come across one?

I'm beginning to think I might as well switch to a Nest or Hive thermostat. Probably Hive as it doesn't require power.

Neil,

There are two main ways of controlling a modern “packaged” domestic boiler in the UK.

The first is the simple on/off switch or providing a power feed to the boiler as the “call for heat”. Most systems are operated this way. No matter how sophisticated or gimmicky the controller is - it merely switches the boiler on or off. Modulation of the boiler et al is all done with the internal control system of the “package”.

The second is an industry standard called Open Term. In this, internal control of the boilers’operating parameters is undertaken externally to the boiler by the thermostat / timer control.

Vallaint, refer to this as Ebus - which is in essence modified Open Term. The issue ( in my view) with Open Term is that it is not yet fully compatible across all manufacturers / suppliers.

What Valliant are proposing to you is to convert your control system to the latter. Unless you are very competent with control system logic, it is difficult to get a Valliant boiler to operate on Open Term unless you use their equipment. I did not think that the Ebus module that Valliant proposed you to use is available from them in the UK. I have always had to purchase them in Europe. I have also had an issue with them over a boiler warranty when a VR39 was used as the interface to control a boiler with their controls!!

If you opt for the first route, there are a number of non Valliant controllers that can be configured to suit your boiler - my preference would be Honeywell, both on grounds of cost and ease / flexibility if you want to upgrade to a more sophisticated controller ( such as Evohome in the future) or compatibility with a new boiler in the future.

Whichever route you follow, you are going to need a plumber / heating engineer familiar with the control system of Valliant boilers. Additionally, they need to be Gas Safe to make the connection / configuration within the boiler casing ( which is in the inside the sealed part of the boiler which makes the boiler sealed from the room).

If it was my call, I would get that person on board now. Their advice / recommendation will give you the most cost effective solution to resolve your issue.

With respect to Nest and Hive I would be wary of purchasing a supply and install package (circa £230) from someone who is not familliar with your boiler type

Hope this helps