Ah, that does make some sense....which is why I'm also getting installers back to put the outside temp monitor Outside! Currently in loft so doesn't accurately show outside temp. 

This sounds like the job was not quite as promised. Will pester installers tomorrow to get resolutions!  

Posted by: @ajbevster

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Ah, that does make some sense....which is why I'm also getting installers back to put the outside temp monitor Outside! Currently in loft so doesn't accurately show outside temp. 

You are kidding me surely.

No?

In which case it's the first time I have heard this particular abomination, I will bear that in mind when asking others about their systems!

Pure weather compensation, without any influence at all from room temperature measurement, works very well for many, including me.  I  turned off completely the built in 'room compensation' function on my controller, which is an overlay to the WC, and the internal temperature is more stable as a result.  Some houses, eg ones which are poorly insulated or have high solar gain, may need additional tweaks but in all cases the starting point is weather compensation. 

In some European countries it's been mandatory for two decades on boilers and heat pumps, sadly we didn't follow suit and as a result many of our houses are less comfortable and we have paid about 10% more for our heating.  Sheer madness but that's how it is.  Now we are paying the price with the need to relearn everything we thought we knew about heating systems!

It doesn't help that the User interface for WC is rubbish on most controllers.  I will have to look up the ideal one.  Vaillant have come closer than most to cracking a sensible interface to WC, presumably because they also sell boilers in countries where WC is mandatory.

Sadly not kidding...

Would you suggest I disconnect my thermostat and just let the ashp run by itself? It looks like wc is enabled...

Managed to find the wc screen and it's set to 1.5 with summer/winter heating limit 21c and room influence 50%....

 Same as the manual...does this mean if I just ignore the thermostat it should be more efficient being on constantly? 

Anyone want to give advice as to what to set the wc to? 1.5 seems high.....I'm thinking try out .75?

@ajbevster, one thing I’ve learned with weather compensation is to start low and adjust gradually. I’d recommend starting at 0.50 and letting it run for at least 24 hours, keeping track of the outdoor temperature during that time. It’s best to do this over 3–4 days of consistent weather if possible. If it’s too cold inside, increase it to 0.75. Every house is different, so it’s hard to predict exactly, but that’s a good starting point in my opinion.

Are you sure it’s the outdoor sensor that’s in the loft?

@editor sadly yes, I'm 100% sure. So it's throwing the system out by about 10 degrees. 

I will be getting it moved ASAP! Can't believe they fit the control box in the loft also! Not best pleased.  

I think with the logic ideal it says 1.5 for 50 @ 0. So I'm thinking looking at the wc curve for this probably 1 might be best but will start low and work way up. Thanks so much for the support. 

Should I also set room influence to 0? 

@Ajbevster If the OAT is reading 10C high then it might be possible to offset this by setting the target house temperature as 10C high until the OAT sensor is moved (and make sure it gets put on the shady side of the building). The heat put into the building by using weather compensation is based on the difference between inside and outside temperatures.

Posted by: @ajbevster

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! Can't believe they fit the control box in the loft also! Not best pleased.  

I would insist they move that too

Posted by: @ajbevster

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Would you suggest I disconnect my thermostat and just let the ashp run by itself? It looks like wc is enabled...

Ideally yes at least initially.  However the ashp may be configured to require a contact closure in the thermostat as a call for heat.  If so you would also either need to reconfigure the ashp to ignore or wire the contacts together to simulate continuously closed.  That's why I suggest turning the station to max as it has the same effect without having to change any settings or wiring.

@jamespa thanks James. Good plan! Managed to adjust the curve to about 1 to compensate for the indoor outdoor sensor...kept the thermostat on max and seems to have solved the cycling inefficiency. 

Regarding noise, plumber has said sounds like air in system and they will come back to fix. 

Sensor and control box should be moved this week. Fingers crossed. When the electrician comes back I'll get him to disconnect the thermostat and make sure the ashp is set up to work without only using wc.

Thanks so much for the help. It's already making a big difference and starting not to panic as much. Hopefully can avoid bankruptcy this month...

@ajbevster I received the following message from Ideal pertaining to your sensor: "You can simulate an outdoor temperature in the installer menu as a temporary measure until the installer returns. Removing the outdoor sensor now will only generate a fault code as the PCB has already recognised one has been fitted."

@editor I did find that in the manual and feel confident enough to give this a go. Can't be worse than it currently. The heat pump must be so confused recording intake temperatures of 0 degrees and the outdoor temp saying its 9 degrees. Thanks again for the support. Feeling much more at peace now.

@ajbevster this makes me want to scream, that ideal heat pump is the simplest heat pump on the market to install. Its a lovely unit. I have one at home, its amazing. Ideal tech will assist you, they offer the best support of all the manufacturers.

give them a ring and they will guide you by video call  how to fix it temporarily. then get the installer back in.

It doesn't matter how simple the installation or the unit is there is always an installer who can balls it up. 

good luck.