Zubadan shows consumed hot water energy bigger than delivered hot water energy

Can you show a couple of photos of your system and the controller, or wherever you are seeing those figures.

We do not have melcloud, I think what we have is pretty basic, setting the hot water just from the zubadan controler. 

​@Morana I'll see if I can get the right people in here for a discussion because I'm not sure I can make total sense what is going on here. ​@BeePee is good and maybe he knows who else to summon

The difference between the energy produced and the energy consumed is greater than 1 (890 / 654) which shows the HP is working but not with a high COP as you would expect. The heating COP is 1.6 which is very poor and the hot water COP is 0.75 which just seems very wrong.

I'm hoping someone else can shed some light on the figures.

Hi ​@Morana 
I saw your figures and couldn't make sense of them. I have a gas boiler so not that well up on heat pumps. I have had a look at my gas usage for January
Hot Water ~ 100 (141) kWh
Heating ~ 1200 (748) kWh

Yours are in brackets.

So your energy delivered for water is similar (just two of us), for heating about half of mine. You didn't say what size house you live in. The calculation on our house using Heatpunk suggested a 7 kW heat pump. Less demand suggests a smaller or better insulated house.

I assume you have followed other guidance on the forum re-heat pump efficiency. Cooler water cylinder (50°C), limiting the use of TRVs, and using constant gentle heating (at flow temperatures less than 50°C).

​@Peter E  has mentioned that the apparent COP figures are poor (dreadful?). So bad that it would be better to ditch the heat pump and use an immersion heater! It's not easy to suggest what is wrong even with details of your system. It needs someone with a Mitsubishi heat pump to go over the settings.

Can you post some photos of the equipment itself showing the back of the outdoor unit and the pipe work around the hot water cylinder. 12kW is big. What size and age is your house? Where in the country are you? The more info you give the easier it is to see what’s happening. 

We have a 240sqm house new house in Romania where the wheater is a bit colder in these months -4 to 2-4 degres at night and 0-10 at day in this month of january (but not how it used to be). Pretty good insulated I would as it is made on wood structure and insulation, I noticed that at -1-0 degrees at night one room lost just 1 degree (from 23 at12 am to 22 at 8pm). We have underfloor heating in the entire house, and the ecodan hydrotank of 200l. Just 2 persons that are using hot water for bath at night. Using 2 thermostats, but yesterday we stopped them and we moved on the wheater compensantion curve to see how it works..hoping to a better COP for heating.

For hot water we asked the person who installed it and he said that the only explanation is that the pump is not showing the corect data..I don’t know what to say, I wanted to know of someone has ever saw something like this…

Photos will help…

Just looked up the recent weather for Bucharest, slightly warmer than here in the UK. Your house is about twice the size of mine so I would be delighted with your heat loss/demand figures (if they are true).

The Hot Water delivered figures look reasonable for a two person household - we generally run two baths a day.

It might be worth looking back at your electricity meter readings to see if they match the consumed figures. I can’t think of an easy way to determine/confirm the delivered heating figures.

I fully agree with ​@BeePee that an immersion heater would be better for the hot water. At least the energy used will end up in the tank. BeePee and I have a similar experience with poor efficiency heating hot water, although for us it is gas not a heat pump but it is a similar situation for a heat pump.

Hey ​@Morana 

Welcome to the Forum! 

I’m really glad to see you’ve already had some helpful replies from our community, I hope they’ve been helpful so far!

It might be helpful to share some photos of the equipment itself.

I’m not sure if the following topic might be of any use to you: