Hi guys,

Ive just taken a meter reading. Its been 25 days since I set the heating to prohibit on the Ecodan.

The Ecodan shows:
Consumed: 80kwh (11kwh DHW; 68kwh Heating); Delivered: 55kwh (45kwh DHW; 9kwh Heating)

The above equates to:

DHW COP: 4
Heating COP: 0.1
Overall COP = 0.6 (!)

Heat pump has used in total 33kwh in past 25 days.

So, with the heating turned off, it used 68kwh with a COP of 0.1!! Perhaps this is the phantom ~2.8kwh per day you mentioned @SUNandAIR . Not sure what else I can try.

Hi @tufty there’s not a lot to be sure about when some info is estimated by ecodan program unfortunately. I think it’s as important to know what information to “ignore” as much as to know what is worth paying attention to. The challenge is knowing which is which!

you’ve made a positive statement copied below. This sounds like a metered reading? Is that the case?

Posted by: @tufty

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Heat pump has used in total 33kwh in past 25 days.

If you have only used 33kwh and you know your DHW has been operating then that might be a valid reason  for the size of energy useage in this 25day period. 

However I would be tempted to query your ecodan data suggesting a COP of 4 for DHW production, since COP stats for DHW is generally around 2 to 2.5 for the ecodan system. However this varies depending on the set temperature you are heating your hot water to and duration. 

• So as a sense check - assuming a 1kw consumption for each DHW cycle over 25days you might expect 25kwh
• Then if you had 2 legionella cycles this requires a higher temperature so may account for more kWh.
• Finally the monitoring system of the ecodan also consumes 0.5kwh per day - as posted by @walkers-heatpump - that would account for a further 12kwh or more.
• I think you said you SOMETIMES heated your DHW every other day

So if you do have accurate metered consumption for your Ecodan then 33kwh consumption might be explained by the above items…

Also if do have a COP of 4 for your DHW then quite a few people might want to know how you’re achieving that because it is a really good achievement.

Cheers @SUNandAIR.

I have the DHW come on for 30 minutes every other day which heats the water to 45 degrees. Very minimal power needed for that, but its enough hot/warm water for me. (also, I disabled the legionella setting!)

I do have a seperate meter for the ASHP, and even an additional meter for the ASHP's immersion heater.

Regards COP, Ive posted about this elsewhere, but its always been a mystery. The heating I can never get a COP of above 2, and DHW always has a COP of about 2.8, giving an overall COP of ~2. Which is pretty dissapointing performance. Someone on the forums (perhaps it was you) suggested that something is not right with the reporting and to get an engineer to look at it. (which I will at some point over the next few months when it gets serviced).

I feel something is not right with the installation, but I cant put my finger on it. No instructions were given when it was commissioned, and I cant find any useful documentation online (other than some scant online brochures). I was pleased to discover this forum! 🙂

I will investigate further, and if I turn up anything I will post here.

Cheers!

Quick question @SUNandAIR : Im going away for a week sunday - following sunday. I obviously dont need any hot water during that week. Shall I just disable it like you showed how to disable the heating above? Or will that somehow damage the system?

I know theres a Holiday Mode on the ecodan, but I dont have time to work out how it works, so just prohibiting the DHW for the week is easier(?)

Hi @tufty,

If you’ve already prohibited the heating and you don’t live in a night freeze risk at this time of the year then why not just switch the unit off from the main controller? 
You won’t get the energy data for those few days but everything will just come back on when you switch the power button back on, on your main controller.

To switch off, press any button on your main controller (to wake up the controller) then press and hold the “suitcase”/on off button. Hold it until the screen goes blank.

To switch it back on, press the “suitcase” button.

press once to wake up the controller then press again to turn the system back on.

We have had our heat pump switched off for the past 2 months since we have solar hot water during the summer months and don’t have any concerns about frosty mornings in our location.

The system still appears to be monitoring itself each day with brief (5second) water flow activity. But apart from that the data gathering on MELCloud is suspended.

Correction: MELCloud does still appear to be gathering data from our thermostats even when it’s switched off see below weekly temperature report….

Lovely - thanks @SUNandAIR - I will do that. 👍

Hi @SUNandAir . Hope alls well.

Even though theres currently no risk of frost yet (I think), do you think its worth me putting the heating back on, albeit in defrost mode? Or do you think its safe to leave it off for another month or so? Im in Devon btw.

@tuftyThere is one thing you can count on - that is you can’t count on the weather! Sod’s Law dictates that if you take the risk, the weather will catch you out! Is it really worth the risk - even in Devon? Regards, Toodles.

Posted by: @tufty

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Hi @SUNandAir . Hope alls well.

Even though theres currently no risk of frost yet (I think), do you think its worth me putting the heating back on, albeit in defrost mode? Or do you think its safe to leave it off for another month or so? Im in Devon btw.

Hi I guess rural Devon can be quite cold over night. If you have anti freeze valves fitted on your outside pipework it’s worth remembering they activate to discharge at 3C. We have our freeze stat function active now but the pump only activates at 5c so it isn’t functioning until it’s needed.

hope this helps

Can you remind me if you have a non standard thermostat and what you mean by ‘defrost mode’. Since you may have a 3rd party controller which I’m not familiar with. 

@sunandair Morning!

Just woken up. Its a cold morning, must have been very cold over night. Im very cold-tolerant, so Im not going to put the heating on until perhaps November. But I dont want to damage the system with frozen pipes etc. So my thinking is to turn the heating from prohibit to defrost.

Youll have to forgive me, my knowledge of ASHPs and how theyre controlled is pretty minimal. 🙂 

Ill explain what Ive got: Mistubishi unit installed 4 years ago (and had it serviced about 3 months ago), so I presume its got freeze valves etc fitted. Theres an Ecodan unit which has heating currently set to prohibit mode. I have UFH downstairs (which I hardly ever use and just have them set to defrost mode). Upstairs, the radiators are controlled by a wall mounted unit and a handheld stat.

So in my situation - when I dont need heating on, but also dont want to have frozen pipes - shall I take it off Prohibit mode on the Ecodan, and press the defrost button on my handheld stat?

Thanks

Posted by: @tufty

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Ill explain what Ive got: Mistubishi unit installed 4 years ago (and had it serviced about 3 months ago), so I presume its got freeze valves etc fitted. Theres an Ecodan unit which has heating currently set to prohibit mode.

Hi 

I’ve found a post from last December where I think you said you’ve got glycol in your system. 
If this is the case then you should be already protected and probably won’t have the freeze valves I referred to above. 

So if you can confirm the system is filled with glycol that will put things on a different footing. It should already be protected against freezing.

I don’t have glycol in my system.

 

 

@sunandair Ah well done!

Yes Im sure the system has glycol in. In fact Ive just dug out the Service Sheet from 2 months ago:

So it looks lik eit does have glycol in(?). What does the -4 in the Notes column mean?