@transparent Beware, the ‘batteries included’ may be flat LR44’s as mine were; I bought a pack of 24 (I think it was) from Amazon and as the company never communicated with me over the flat LR44’s, I contacted Amazon and informed them - and requested a refund on the purchased LR44’s, which they did!

I am unsure where in RHH but there is some guidance from Derek M on ‘calibrating’ these probes as they are all slightly different in their accuracy stakes!

By bundling the metal probes all closely together and then placing them in a draught free position, observe the readings over an hour or so and make a note so you know how much compensation to allow when using them for comparison purposes. (I use 4 on my LLH pipes to optimise the pump speed.)

Posted by: @econonsense

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I think its set at 45

You need to check what it is actually set to. I am not familiar with your brand of heat pump, but it should nonetheless give you some form of monitoring what it is up to. The three port two way valve usually means it is either doing space heating or hot water heating. How long does the hot water period run for? As an example, I have my hot water heating timed to be on for an hour between 1300 and 1400 daily. If the tank is below 40 degrees, which is the trigger temp for a reheat, it will start reheat at 1300 and it usually takes about 30 mins or just over depending on initial temp to get to 50 degrees, which is my set temp. Once it has got the tank to 50 degrees, it returns to space heating.

@econonsense I see that Cathoderay said they're HIES registered, which is good news. Doesn't help you now, but if you call HIES on Monday and lodge a formal complaint, HIES should kick Eco247 into high gear if what they said in a recent interview I had them with was true:

@editor I think you might be forming a ‘Special Relationship’ with ‘the trade’ via your Q&A’s Mars! Regards (and approval!) Toodles. 😉

Posted by: @econonsense

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would this be to monitor in / out on water tank?

Yes. We can measure in/out on the water tank, and also compare with the pipes coming in from the HP itself.

That will allow us to see if the pipes are losing heat when they pass through the external walls of the house.
They should be insulated all the way through.

@cathoderay Hi I'm fairly sure they set the HW tank to 7:30 - 9 am and again at 15:30 until 17:00 daily.

They also put the legionella heat to 15:30 to 17:00 once a week to save elec

@econonsense - if that is the timing, then it has long enough to heat the water - but to what temperature? You need to find out what the set (target) temperature is. It should be accessible, not buried deep in layers of impenetrable menus. If it is set too low, then that will explain a lot!

Not everyone uses legionella cycles, as the actual risk in normal domestic settings is extremely low. 

Moving on to space heating, I infer if your system is set to deliver 19 degrees room temp all the time then it is probably running on weather compensation, which is how it should be. Weather compensation works by altering the leaving water (flow) temp in response to the outdoor air temp, the colder it is outside, the higher the LWT. The settings for this are crucial (usually set by defining each end of the curve), and usually involve a lot of trial and error to get them right. You need to check the following:

(1) is the system using weather compensation? If it isn't then what is it using?

(2) if it is on weather compensation, what are the settings? Look in your manual to see how to do this (if you haven't got a manual, find one online). Typically the settings will be something like 45 @ -2 ie LWT 50 degrees when -2 outside which is the left hand end of the curve (which is actually normally more of a straight line) and 25 @ 15 ie LWT 25 degrees when 15 degrees outside. LWTs might be slightly higher in old leaky buildings, mine are.

Without knowing these basic settings, there is no way of making sense of your system, or why it is performing so poorly.

@cathoderay Hi Many thanks for all your input and efforts,

The water is set to 45, I will try to look at the menus tomorrow.

The whole system is outside in a metal shed with no lighting!

Cheers

@econonsense - tomorrow is fine. Is there not some sort indoor controller panel? That is where you would normally get and set the settings? Very few of us want to venture outside on dark and stormy nights!

@cathoderay Hi I have a thermostat display in the house, it may have settings in it, the main controllers are in the shed. To be honest, I have no idea what most of the settings are so I'm loath to play with them. My water was back to normal temp this morning, but the outside temp is quite decent today. So it seems entirely dependant on how cold it is outside.

Posted by: @econonsense

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My water was back to normal temp this morning, but the outside temp is quite decent today. So it seems entirely dependant on how cold it is outside.

That suggests the heat-pump is responding correctly, but that the heat is being lost to the atmosphere when the DHW travels through the pipe into the house.

• Can you see that pipe?
• Is it insulated?
• ... all the way through the wall into the house?
• Is the pipe insulation sealed to prevent ingress of water?
• Is the insulation UV-resistant?

A photo or two would be really useful at this stage 😀 

Posted by: @econonsense

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I'm loath to play with them

I'm afraid it comes with the territory. If all installers were perfect, and always did a perfect handover, things would be different, but that is not the way things are. Plus tweaking and fine tuning weather compensation is arguably better done by the occupier, because the process can take some time, and  only they know exactly what they find comfortable. I think you said in an earlier post you were a mechanical and electrical engineer, getting hold of the manual and making sense of the controls should hold no fears for you!

The DHW heating doesn't use weather compensation, so it itself should run broadly the same whatever the outside air temp. If the losses are OAT dependent, then as @transparent says, it suggests the losses, which must be colossal, must happen outside the heat pump, either on the way to the DHW tank, or at the tank itself.