Vaillant 438 boiler - hot water only not working

[mickyg]

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[hothead]

I talked to Vaillant on Friday about exactly the same issue, prior to an installation. They told me that the 140 can control hw and heating without the V65. Please tell us how it goes.

 

[mickyg]

I talked to Vaillant on Friday about exactly the same issue, prior to an installation. They told me that the 140 can control hw and heating without the V65. Please tell us how it goes.

its not possible. Look at the boiler wiring. You would need 2 seperate live outs for hw and ch, which there is not. Won't work, simple. It can only control the system by ebus, which requires the VR65.

 

[gas4you]

On its own it can on a combi, but needs the VR65 on a standard system.

 

[mervmatt]

You must get a VR65 installed. The 140 needs to talk to this via ebus and not 240VAC.

The zone valves, room stat and cyl stat are then all connected to the VR65, not a normal wiring center. The VR65 has its own 240VAC supply and fused isolator switch.

Vaillant tech help are useless, only good for giving you a large phone bill.

Thanks for all your help everybody. My husband has now decided to rewire this to our original external programmer, a Tempus 7, which has always worked well and which we are all used to. Can't believe it's possible to spend all this money on an expensive boiler only to find, after you have opened the documentation, that you need to buy, in addition to a programmer, an additional item for the programmer to talk to. Why don't they tell you beforehand? Also, it's even more confusing because the heating is working fine and the hot water too, as long as we have heating mode on. Can't have been that much more difficult for them to have made it so that you can use hot water independently without having to go to more expense. Guess it's just another moneymaking exercise for the manufacturers.

Anyway, thanks again to all of you, always good to get a little more education.

 

[mickyg]

Guess it's just another moneymaking exercise for the manufacturers.

The boiler is designed the same as any other. However they've given the option of using branded controls which uses a low voltage ebus system, which for weather compensation works nicely. The problem is the incompetent numpty who installed it. Anyone with an ounce of electrical savvy can see it won't work.

 

[hothead]

I talked to Vaillant on Friday about exactly the same issue, prior to an installation. They told me that the 140 can control hw and heating without the V65. Please tell us how it goes.

its not possible. Look at the boiler wiring. You would need 2 seperate live outs for hw and ch, which there is not. Won't work, simple. It can only control the system by ebus, which requires the VR65.

OK, I've looked at the papers, and its obvious. No independent control. Only way is to use the roomstat to switch the ch off. Cheers.

 

[mervmatt]

Guess it's just another moneymaking exercise for the manufacturers.

The boiler is designed the same as any other. However they've given the option of using branded controls which uses a low voltage ebus system, which for weather compensation works nicely. The problem is the incompetent numpty who installed it. Anyone with an ounce of electrical savvy can see it won't work.

In their defence, this is the first boiler of this type that the Corgi reg. plumber has installed and the electrician is a domestic installer who has only wired up a couple of boilers before, neither of them with an onboard programmer. I don't think either of them have been incompetent as they are both known personally to us and their work is highly recommended. I think it is just a case of this one being a little different from what they have both been used to and none of us understanding about needing the vr65. Anyway, enough said, thanks again for help.