Beiträge von mirthquake

You're awesome! Thank you so much for this suggestion. Works like a charm!

Hi

I recently installed a Shelly 1PM Gen4 switch on a relay circuit to control my hot water cylinder. I then set up a schedule to turn the hot water cylinder on from 03:00 to 05:00 every day when my power is cheap. There are, however, days when I want to keep the hot water cylinder permanently on all day, e.g. when we have guests at home and the hot water usage is high, or on days when we have free power. I initially assumed that if I just flick the input switch to the device on, the output would stay on all the time, irrespective of what schedules are set. What I'm seeing, however, is that when I flick the input switch on, the output does turn on immediately. Then at 03:00, when the schedule starts, the output continues to remain on. At 05:00, however, when the schedule expires (flip value after 7200s = 2hr), the output turns off despite the input switch remaining on. Is this expected behaviour? Can this behaviour somehow be circumvented? I'd ideally like the output to remain on as long as the input switch remains switched on. I want the schedule to control the output only when the input switch is turned off. FWIW, the input mode for the input switch is set to "Switch" and the output type for the output is set to "Toggle".

Any assistance would be much appreciated.

Thanks!

Thanks for that. I did not know that device existed. In any case, have installed the 1PM in a relay circuit. That pretty much means its power management features are now useless, but it's a small tradeoff.

thgoebel, others - Quick follow up question. Would you reckon it would be a good idea to connect a Shelly 1PM Gen4 in series with a 3kW hot water cylinder that is expected to draw around 13A current on a 230V connection? It's pretty close to the 16A rating and I've read some reports online of the Shelly switch heating up to very high temperatures when installed in such configurations. Considering it will be installed in the wall cavity within the hot water cylinder closet, it won't really have much ventilation either. Thanks!

Oh that's a great idea! Don't know why I didn't think of that. Think that should solve my problem. Thanks a lot for your assistance!

thgoebel - Thanks lot for your response. I actually did try something like this, but what I noticed it did was turn the cylinder off immediately (less than second) after it turns on at 03:00 since the instant it turns on, the power usage does not immediately jump up, but starts low and gradually builds up to 3kW over few minutes. Ideally, this rule should kick in only after the power usage has built up to around 3kW.

I recently purchased a Shelly 1PM Gen4 switch to control my hot water cylinder. Sorry for posting in the Gen3 forum, but I couldn't find a dedicated forum for the Gen4 switch.

My plan is to have the switch turn on my hot water cylinder at 03:00 every day when our power is the cheapest. I realise this is trivial to achieve with the Schedules feature.

The second thing I'd like to achieve is once the cylinder has been turned on at the specified time, it must turn off as soon as the water has reached the set point temperature and the power consumption drops. This is to ensure that the hot water cylinder doesn't keep turning the heating element back on during the day as the water temperature slowly drops, since my power is rather expensive at other times and the small drop in temperature until 03:00 the next day does not bother me much. The turning off of power to the cylinder has to be based on drop in power usage and not time-based since the amount of time taken to heat the water to the set point temperature can vary based on the hot water usage in the previous day. How can I achieve this? Can this be achieved using the Actions feature, or would I have to write my own custom Shelly script? If I have to go the route of a custom script, could someone please point me in the right direction? I'm a first time Shelly user and am finding the documentation online a bit difficult to navigate. ChatGPT isn't of much help either.

Thanks a lot!