Do I actually control hot water?

AntCW

Hello,

I am not sure I actually control hot water. I have hot water, and the heating works fine, but the hot water has been turned off in app for three days now. I would want to save a bit on electricity bill by not having hot water on at all times, as it seem the case is now.

Old System: danfoss fp975 controller; Valiant ecotec 630 for heating only( does not supply the taps at all) , Megaflo cylinder for hot water.

Tado: Wireless receiver with Hot water control, SmartsThermostat ( and the bridge, ofc)

Light comes on the wireless receiver when I switch on the hot water, but there's no noise from the cylinder. It does make some noise when I switch on heating. Heating has been off since the install about a month ago and I have hot water, so it does not seem hot water comes on when heating is on.

Danfoss had an Auto mode, could it be it is in one now? The old wiring was very simple: CH ON, HW ON, L and N. I wired it according to Tado app and bridged CH COM and HW COM. Again all is working, but I seem to lack the hot water control.

Anybody can advise if faced with a similar challenge? Thank you!

AntCW

For those that will come across this: what I thought is Danfoss FP975, as it looked like one, was wired like an FP715. So my HW ON was wired to HW NC on tado, so my heater was always on! No wonder I had scalding hot water at all times! For similar novices: either will work, FP715 is dead easy to wire. 3 is HW ON and 4 is CH ON on tado. Bridge COMs and done. NOTE: 2nd DIP switch at the back, check if it set to Gravity or Pumped!

NOTE: 2nd DIL switch at the back, check if it set to Gravity or Pumped as it would be needed for correct set up.

johnnyp78

As far as I can tell from this the hot water is only supplied by the cylinder and not by the boiler? That’s a non standard set up, it might be why you’re having problems. When you say you’ve bridged com, have you also bridged l to com and wired in NO? Do you even have an s plan or y plan set up?

AntCW

Thanks for taking time to reply, johnnyp78.

I think that's right - boiler is not even set up to supply hot water, it's a Vallaint ecotec 630, and when it on, it just supplies rads( there not even an option to select hot water supply); nevertheless the old and new tado set up works, as in I have heating and hot water. I think I have a Y plan as there's only one valve, and the property is a flat, which makes me think it's a Y, but I am not a plumber, so don't know. I have bridged L with COMs and again, all works, and based on the consumption pre and post tado install, it does not seem the cylinder is always on and just cycles through on and off, as the meter readings are broadly the same. Spoken to tado and will send wiring photos to them but not inclined to tinker with this as again, all works, just can't explain why I seemingly have no control over hot water.