Underfloor heating controls drawing too much power

record

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 (not the air-to-water heatpump itself outside the house) is the culprit. 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 €900 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.

10-10-20

400w is a considerable amount of energy to be 'lost' alright. Typically those types of loss will either be in the form of heat or mechanical power. To dissipate that amount of heat from a device you would need a large surface area - or the device would be as hot as 4x 100w lightbulbs. Do you feel heat off the device at all when the loss is present for a period? Is there any sound off the device or signs that a pump could be running? What is the heat-source for the UFH system - is it geothermal or external air heat exchanger? Any chance that these run continuously?

Just in case it's a measurement error (not unheard of with some measurement devices) you should perform a meter read to check the usage. The best way to do that would be to turn off any unused circuits (except the lighting) and then take a measurement and leave the system running for 1 hour and then take another measurement.

A photo of the control panel and the UFH system might also help.

drury..

It makes the case for energy monitoring 😁

record

Thanks @10-10-20. The controller (grey box in picture below) is Alpha Innotec Luxtronik (manual attached). By the way, the picture shows an red error message on its LCD, as it is an old picture.

AIT_Heat_Pump_User_Manual[1].pdf

Do you feel heat off the device at all when the loss is present for a period?

Is there any sound off the device or signs that a pump could be running?

No to both.

What is the heat-source for the UFH system - is it geothermal or external air heat exchanger?

Any chance that these run continuously?

It is an external air-to-water heat exchanger. The unit outside is not running at the time the 400w is being used.

Just in case it's a measurement error (not unheard of with some measurement devices) you should perform a meter read to check the usage. The best way to do that would be to turn off any unused circuits (except the lighting) and then take a measurement and leave the system running for 1 hour and then take another measurement.

Thanks, will look at that.

smuggler.ie

https://www.boards.ie/discussion/comment/122611904#Comment_122611904

"It is an external air-to-water heat exchanger. The unit outside is not running at the time the 400w is being used."
How you determine that?
I might be well wrong, but some(or all) of those air-to-water systems are fitted with "heater" to cover-up once the exchange of heat cannot be produced to the demand and/or to heat water enough to battle bacteria problem (>60C) - effectively immersion heater.

smuggler.ie

Consult with manufacturer/installer and see if this apply in your case

From your manual:
"2nd heat gen. 2 type:
no means:
no 2nd heat gen. is connected, the output has the function error signal
heating rod means:
a heating rod is connected as 2nd heat gen., bivalent operation of the installation"

From SEAI p27
"5.2. Bivalent alternative
In bivalent alternative mode, the heat pump switches off for a period of time and the load is met by other heat
sources. An example of this is when the flow temperature required is higher than the heat pump can provide. In
space heating systems, this could be triggered by the outside temperature dropping below a predetermined value.
In process heating, it could be a request for a higher temperature from a system controlling a piece of the process
plant."

smuggler.ie

Quite critical, but i like it.
And i hope this does not apply to you
https://www.youtube.com/watch?v=GhAKMAcmJFg

record

Thanks @smuggler.ie. In response to your question:

"It is an external air-to-water heat exchanger. The unit outside is not running at the time the 400w is being used."
How you determine that?

I determined that on the basis that there is no sound or vibration, etc. from the air-to-water unit. When that unit is active, it is easy to hear it (and see it on the app that shows me the present electrical load on the house).

Consult with manufacturer/installer and see if this apply in your case

From your manual:
"2nd heat gen. 2 type:
no means:
no 2nd heat gen. is connected, the output has the function error signal
heating rod means:
a heating rod is connected as 2nd heat gen., bivalent operation of the installation"

Thanks, I'll check that out.