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- 12 Nov 2019
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For two years now we've been strugging to achieve modulation of our central heating, and I'm starting to wonder whether the VR66 is the problem. Here's our setup:
vSmart thermostatic controller, connected to...
VR66 Wiring Control Centre with NTC sensor for hot water cylinder, connected to...
Vaillant ecoTEC Plus 624 system boiler.
Our problem is that the boiler has never modulated when running the central heating. It charges the hot water cylinder without any problem, scheduled to do so at the end of the evening when there's no heating demand. However, when there's a central heating demand from the vSmart, the eBUS heating flow temperature being requested (D.009 on the boiler display) is ridiculously high: - we've seen 90°C when it's 1°C outside and the heating curve is set to 0.9 on the vSmart.
Once the boiler's fired up, the heating flow temperature doesn't change at all, with the result that the room temperature overshoots by 0.6 or 0.7°C. This isn't the modulating behaviour advertised by Vaillant. In the next cycle, when the boiler next fires up, the requested flow temperature may be different from the previous cycle, but it still refuses to modulate, and it's usually above 60°C, even on a mild day.
We've had our vSmart replaced in an effort to sort out the problem, with no effect. We've done a factory reset on the boiler, again with no effect. We've asked the Vaillant "Controls Champion" whether it could be the VR66 that's at fault, but he reassures us it's a basic switching device, so the problem can't lie there.
Is there anyone out there with some expertise who could share their thoughts?
Matthew
vSmart thermostatic controller, connected to...
VR66 Wiring Control Centre with NTC sensor for hot water cylinder, connected to...
Vaillant ecoTEC Plus 624 system boiler.
Our problem is that the boiler has never modulated when running the central heating. It charges the hot water cylinder without any problem, scheduled to do so at the end of the evening when there's no heating demand. However, when there's a central heating demand from the vSmart, the eBUS heating flow temperature being requested (D.009 on the boiler display) is ridiculously high: - we've seen 90°C when it's 1°C outside and the heating curve is set to 0.9 on the vSmart.
Once the boiler's fired up, the heating flow temperature doesn't change at all, with the result that the room temperature overshoots by 0.6 or 0.7°C. This isn't the modulating behaviour advertised by Vaillant. In the next cycle, when the boiler next fires up, the requested flow temperature may be different from the previous cycle, but it still refuses to modulate, and it's usually above 60°C, even on a mild day.
We've had our vSmart replaced in an effort to sort out the problem, with no effect. We've done a factory reset on the boiler, again with no effect. We've asked the Vaillant "Controls Champion" whether it could be the VR66 that's at fault, but he reassures us it's a basic switching device, so the problem can't lie there.
Is there anyone out there with some expertise who could share their thoughts?
Matthew