4 Sep 2012
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United Kingdom
Hi, New to the forum but a real problem with my controls. This is a new installation, I have a vaillant ecotec plus 624 system boiler with a vrc 430, vr61, vr81 for HT zone 2. The system is designed as in diagram 4 in the vr61 instructions. 3 x 2 port honeywell valves. I have a vr10 sensor connected to the black and orange harness at the back of the boiler ntc tank. The problem is hot water. It has a mind of its own. when setting up the vrc 430 you can test the actuators and they all work fine but put it in to auto or manual and nothing happens even when hot water storage is cold? I have changed the vr10 thinking it was the sensor but still no differance. Like i said the heating works fine. I also have installed secondary loop bronze pump controlled by a vr40 in side the boiler. Also not working? The vr10 sensor inside the tank is reading correct.
Any advice would be great. Regards Matt
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I would say that this is almost certainly some settings... why not get your installer to ring Vaillant technical for some help?
Who installed the boiler for you?

What do they say about it not working?

I installed the boiler and controls and i always thought i new quite a bit about vaillant boilers guys. I have to say i have had the hot water regenerated by the boiler but its intermittent. When it has worked which i can count on one hand, i notice the boiler does modulate in hot water mode but the control stat on the fasia of the boiler is overridden and shuts off about 80c when its only set about 60-65c? Like i said in heating mode it works a treat. I have a low loss header system with a 22mm danfoss avdo bypass to keep the flow rates up with low water content radiators. Have phoned vaillant but no joy of sorting it and its installed to book. Regards Matt
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How can you have a low loss header and an auto bypass?
Yes tony i have a header on the boiler but from there i have a grunfoss 15/60 pumping to the heating zones from the header. 22 mm bypass to releave the 15/60 when the thermastic valves start to shut down.
OK then, I suppose that is not totally unreasonable although I would not have expected that pump to have been powered when no valve was open.

The auto bypass valve is only required to allow a flow through a boiler as part of the pump over run to dissipate heat. That does not apply with a LLH though.

there is no down side to the by pass, but it shows a misunderstanding of the function of the weather compensation (vrc430) this will vary the radiator temperature rather than the TRVS...

An alternative set up would have been a variable speed pump (CP) and TRVs in fewer but not all rooms...
Just an quick update and yes i have found the problem. After a long phone call to vaillant and a new Vr61, all is working well.
Faulty vr61
Regards Matt

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