Smart meter accuracy & hot water problem

Muahahaha

Got a SM and on reviewing my usage on the ESB website it shows a spike of 2kw between 8am and 10am every day which has to be the hot water cylinder heating up. But the water is supposed to be heated up sometime between 12pm and 7am during the night meter time fram. Then also the clock on the Horstman Q7 controller for the hot water is set to the correct time. So Im not sure what or where the problem is, either the smart meter data is not correct or my controller shows the correct time but the programming for when the hot water heating comes on is broken or something?

graememk

https://www.boards.ie/discussion/2058355020/smart-meter-accuracy-hot-water-problem

are you seeing it heat (use electric) overnight too?

Muahahaha

https://www.boards.ie/discussion/comment/122231879#Comment_122231879

no, the usage graph shows Im using about 0.25kw between midnight and 8am which Im guessing is from the fridge and the broadband router and a few standby lights on the tv & satellite box. Then at 8am the usage rockets up to over 2kw per hour for the next two hours. Which would lead me to believe that either a) the smart meter data isnt accurate on the time of actual usage or else somehow the Horstman Q7 hot water controller is not kicking in during the 12-7am night rate times. But the time on the dial on the Q7 is set correctly so I dont know whats going on or where the problem lies.

graememk

https://www.boards.ie/discussion/comment/122233149#Comment_122233149

Just as a sanity check, check the meter serial number (it's in the HDF file) to your meter serial number.

There has been someone recently that their serial number was mixed up with another house!

Is there any indication on the hot water controller that it's heating or on?

If you check it at 8am and see what it's doing, even listen to the immersion if you can hear anything?

Are you heating the sink immersion? They usually run at 2kW while the bath immersion usually runs at 3kW

bullit_dodger

Also, just so your aware muahahaah, most Day/Night tariffs run from 00:00 (midnight) to 09:00am in the summer time. Smart meter tariffs can in theory run any high/low mix they want in 30 minute blocks, but assuming your on the old bog standard night rate, you should be good until 9am anyway with the cheaper rate.

That said, I'm inclined to think like you/graeme that something is off there. How big is your cylinder in capacity? 125 , 150 liters etc. and is it 2kw for exactly 2 hrs everyday. You seem to be putting 4kwh into the tank which would be a lot if it's only a 125 liter tank. (too much to heat that water)

Aside: In winter time when the clocks go back, the cheap night rate is from 11pm - 8am.

Muahahaha

https://www.boards.ie/discussion/comment/122233628#Comment_122233628

yeah Im away for the weekend but I should have listened to the cylinder at 8am to hear if its on. In any case Ive knocked the hot water heating off for the weekend so when todays smart meter data comes through tomorrow I'll take a look and if the line is flat from 8am to 10am I'll know its definitely the water heating.

https://www.boards.ie/discussion/comment/122233762#Comment_122233762

Ive honestly no ideas of the size of the cylinder or how to find out. Doesnt help that its deep under the stairs with a washing machine in front of it!

Thanks for the clarification on 12-9am being the current night rate times. But my smart meter data is showing a spike in electricity usage from 8am to 10am meaning if the data is time accurate then Im heating water on much higher day unit rates for an hour.

Im thinking now this is a problem with the Horstmann Q7 controller. But Im unsure how they're programmed inside, I had always thought they turn on in the middle of the night like 4am or something but clearly not in my case, it seems to be switching at 8am despite being on the summer time setting. Id much rather to get that back to 4 or 5am so as not to be skirting with day units at three times the price of night units.

slave1

Take manual readings of your SM for a few days, should be the same as ESBN records but just to rule it out

spose

if it’s the old dial type horseman you’ll need to take the cover off to set the working time. Can search user manual on line or YouTube.

bullit_dodger

https://www.boards.ie/discussion/comment/122234644#Comment_122234644

Thanks for the clarification on 12-9am being the current night rate times. But my smart meter data is showing a spike in electricity usage from 8am to 10am meaning if the data is time accurate then Im heating water on much higher day unit rates for an hour.

True possibly, but at least your only heating it for 1 hr on day rate and not 2 hrs like originally you thought you were. You can (roughly) determine the volume in liters via some easy math.

https://www.calculatorsoup.com/calculators/construction/tank.php

Once you figure out a rough size in liters with https://gettopics.com/en/calc/water-heating-calculators you can figure our again roughly the amount of energy to heat the water that you have determined. Remember that the immersion won't heat -all- the tank but maybe the top 2/3 of it. Eg. if you were heating 150L from 25c → 60c everday, this is.

Then if this is way out on what your seeing for the readings, for example, your seeing 2 KwH used, and above your using 6Kwh then it's probably something else also.

Muahahaha

thanks, have taken a look at that and will try to figure out the size of my hot water tank.

In any case Im 99% sure its the Horstman Q7 that is somehow out of sync because Ive now noticed the mechanical 24hr clock has been sliding back by a couple of hours every 2 days or so and not keeping time properly. Im going to look at upgrading it with a smart control, just not sure which are the better ones and have to do some research. For now though Im just manually heating water using the boost function every night for an hour after 12pm to get the night rate. Then I turn off the water heater so it doesnt try to reheat it again at 8am.