Underfloor heating controls drawing too much power

[heatpump]

I have an underfloor heating system in my house. It is Alpha Innotec, installed in 2006 and it normally works ok.

In the last year or so, I have an app that shows current electricity usage (load) of the house. This shows me that the house is using about 600w per hour at night or when the house is unoccupied, even though the UFH is turned off. By a process of elimination (turning off switches and trip switches), I determined that the underfloor heating control unit (manual attached) seems to be the culprit (not the air-to-water heatpump itself outside the house). It seems to be using around 400w consistently, even when the heaptump is not operating. (I have the UFH switched to 'off' and all the room stats are off). There is no hum off it and no circulating pumps are operating when this power is being used.

When you do the sums, it works out at about £800 per year in seemingly wasted electricity.

I am baffled as to why it would be using so much electricity. Any thoughts as to what the problem might be?

Thanks very much for any comments. Picture below shows the grey control unit in the hot press (the error message on its LCD is just because this is an old pic - it doesn't currently show an error message).

 

[EFLImpudence]

How have you determined the 600W figure? You cannot use 600W per hour.

If you mean 600Wh - Watt-hours - then overnight that is not very much but you go on to say that 400W is being used constantly which is quite a lot.

 

[heatpump]

Thanks @EFLImpudence for your reply. Sorry if I'm getting terminology mixed up. Around 600w is being used constantly, with around 400W of that appearing to be drawn by the underfloor heating controls.

I am able to see the usage through an app that I have that shows the electrical load on the house, which can give a graph of usage over a day, etc.

 

[martygturner]

Heat pumps use power even when off( or more specifically in standby) to keep the crank case heater up to temp. 400w sound about right for a heater...

 

[Why Not Indeed]

Can you check if the UFH mats are being fed by the controller when it's drawing 400W? Seems pretty unlikely it would be some internal malfunction in the controller, without you noticing the controller itself being unusually warm, which you haven't mentioned.
Can you safely disconnect the UFH mats one by one? If you can get a clamp-on ammeter around individual conductors you don't even have to disconnect them.
ATEOTD though this is all speculative, you will probably need to get someone in to fix it anyway, right?


EDIT I think I have for some reason assumed this is dry UFH not wet UFH, so my post is irrelevant.

 

[Rodders53]

What App is being used to show energy consumption? (Smart meter app, perhaps?)
Double check that 600Watts is being drawn via actual meter readings (not IHD) an hour or two apart rather than relying on the app?

The unit has a nominal 18VA (Watts) draw with no external items connected, from specs in part 2 of the manuals for it (Google if you don't have it).

I suspect that you are seeing the Vampire Load of some marques of heat pump that has been mentioned, in post #4. Not all heat pumps use or need such. Research your make and model of pump?

If you have a smart meter In Home Display use that in kWh currently in use mode... Switch that red 'heat pump' isolator to off and see if the power consumed drops by 400 Watts, or not?
{Of course, if that isolates the Luxtronic Controller as well then that won't work!}

No IHD you'll need to repeat the meter reading measurement.

Other, more invasive ways include measuring the current drawn with a meter.

 

[ericmark]

My software also shows what is being used some I can work out, the freezer for example but that does not account for 323 watt even when allowing for using four freezers, so I have two tools to help, this is great for sockets, it gives me a time-power graph, so the freezer for example I can see it switching on/off, and also see the average. The first half the upright freezer the second half is the chest freezer the upright has a auto defrost which is why it uses a lot more power and why there are peaks and troughs.

But where not using a plug and socket, then I need the clamp on ammeter here checking earth leakage but to check what each RCBO uses, I need to either open the consumer unit, or turn items off. I have tried, and it does seem it is rear of house ring final where the unknown power is used, but it is so small and varies so much I have not investigated further. Likely the Sky box or router which I would not switch off anyway so why worry.

Using the in house display (IHD) for smart meter is in the main useless, as most of the time it shows export, and the solar panel software has a delay as the server is in china, so I can make two cups of coffee, carry them upstairs, and the software is still showing the kettle is using power.

So to use the solar software to find what is using power is not easy, and the smart meter is even worse.

So 400 watt, on a smart meter not easy to isolate, turn items off, and on turning on again often some initialisation will draw power, so the big question is it worth it? 400 watt at 8.95p off peak and 31.31p peak = £2.56 per day or £933 per year, so yes a lot of money, I blame freezers for my bill, and 4 trips a week for shopping v 1 trip a week with nearest town 8 miles away, they still pay for themselves.

Personally I would not consider a heat pump, as you simply can't afford batteries and solar panels large enough to keep them running in a power cut, I remember the problems in our winter of discontent and have vowed I will not rely on electric again. Each time we get a little wind we read how so many people are without electric, so it is a non starter for me.

 

[Why Not Indeed]

heatpumpmonitor.org has real-world monitoring data for various models of heat pump, see if someone else has one of yours there for comparison.

 

[heatpump]

Can you check if the UFH mats are being fed by the controller when it's drawing 400W? Seems pretty unlikely it would be some internal malfunction in the controller, without you noticing the controller itself being unusually warm, which you haven't mentioned.
Can you safely disconnect the UFH mats one by one? If you can get a clamp-on ammeter around individual conductors you don't even have to disconnect them.
ATEOTD though this is all speculative, you will probably need to get someone in to fix it anyway, right?


EDIT I think I have for some reason assumed this is dry UFH not wet UFH, so my post is irrelevant.

Thanks @Why Not Indeed . The system is actually wet UFH, with an air-to-water heatpump.

ATEOTD though this is all speculative, you will probably need to get someone in to fix it anyway, right?

Probably will, but I am trying to figure out what the problem is so that the person can fix it. I spoke to the service guy by telephone and he couldn't understand what might be happening, so just trying to see what people think.

 

[heatpump]

What App is being used to show energy consumption? (Smart meter app, perhaps?)
Double check that 600Watts is being drawn via actual meter readings (not IHD) an hour or two apart rather than relying on the app?

Thanks @Rodders53. The readings I am getting are not from an IHD, but from an app that came with our PV solar panel system. This monitors current load on the house (as well as details on the solar PV system). When I switch off the UFH control unit, the app shows in real time a drop of around 400w in the electrical load. I have cross-checked the readings from the app with the electricity meter on the house and it seems to be quite accurate.

If you have a smart meter In Home Display use that in kWh currently in use mode... Switch that red 'heat pump' isolator to off and see if the power consumed drops by 400 Watts, or not?
{Of course, if that isolates the Luxtronic Controller as well then that won't work!}

Yes, I did that to narrow down the problem. The 400W draw is definitely from the Luxtronic controller, and not from the heat pump itself outside. There are circulating pumps attached to the Luxtronic, so I was wondering if they were somehow drawing the power. I looked into this, but the power is still being drawn when the circulating pumps are not operating.

Thanks for you other points.

 

[ericmark]

Thanks @Rodders53. The readings I am getting are not from an IHD, but from an app that came with our PV solar panel system.

That is also what I use, the display however is a mixture of direct and from server readings, so it can give misleading results. If I compare the results here to my IHD on the smart meter they rarely match minute by minute but do day by day.

 

[heatpump]

That is also what I use, the display however View attachment 355813 is a mixture of direct and from server readings, so it can give misleading results. View attachment 355814 If I compare the results here to my IHD on the smart meter they rarely match minute by minute but do day by day.

Thanks @ericmark. When I turn off the power switch on the wall controller, there is an immediate electricity usage drop of around 400w that can be seen through the app I use. When I tun it back on again, it goes right back up.

 

[Rodders53]

Ok... Now that controller has multiple mains outlets for things... judging by the book and a fast skim read of it.
Indeed it states that the power to the outdoor unit is fed via it... but at a max total input load of 6A-ish that may not be true? Certainly it should have an electronic data bus controller between both items to work as designed?

Those other mains feed/supplies may need measuring, using a meter, individually --- if one can get a clamp meter over the individual cables with covers off safely... The alternative is even more risky for the unwary /non-competent.

Whether your maintenance technicians or even the original installation company can throw any light on stuff, I don't know. Obviously if your current person has no idea, and wasn't original installer, he may need to spend some time to find out what is happening.

You may need to pay quite a bit to someone to find this load... which may be normal for the stuff the controller is operating?

heatpumpmonitor.org has real-world monitoring data for various models of heat pump, see if someone else has one of yours there for comparison.

That manual mentions the ability of the Controller to send remote data to that very site...
Also an ability for remote service checks/settings. Subject, of course, to internet connectivity... and potentially optional extras being installed.

It's all rather complex and ultra configurable. My brain hurts just from skim reading bits of the manuals.

 

[flameport]

. It seems to be using around 400w consistently, even when the heaptump is not operating.

If that grey box was really using 400W continuously, it would have melted by now.
400W of heat is going somewhere. Possibly to something connected to that grey box, but not the box itself.

 

[heatpump]

If that grey box was really using 400W continuously, it would have melted by now.
400W of heat is going somewhere. Possibly to something connected to that grey box, but not the box itself.

Thanks @flameport, I will try to see if there is anything connected to the grey box that is drawing the power..