@johnmo no set backs in winter, just 24/7. I did get it to the point that it was working better but before that there were some days when it was very damp air and at 3/4 degrees just defrosting every 40 minutes or so all day so it struggled and then the outside temp would go to -5 at night. 

it ended up OK but it’s clear that we have missed out by not having a LLH or volumiser fitted. 

Posted by: @marvinator80

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@johnmo no set backs in winter, just 24/7. I did get it to the point that it was working better but before that there were some days when it was very damp air and at 3/4 degrees just defrosting every 40 minutes or so all day so it struggled and then the outside temp would go to -5 at night. 

it ended up OK but it’s clear that we have missed out by not having a LLH or volumiser fitted. 

The grant volumiser are quite good. Hook up as per their instructions think they say in the return pipes.

@dodgyknee hi, here's Group 46 parameters changed from default for me, default in [ ]

46 00 = 3 [0] heater enabled in supplementary mode

46 01 = 45.0 [50.0] set this to your maximum design LWT in heating

46 02 = 1 [5] 1 min delay on heater activation in defrost

46 05 = 0 [600] no integration time, there's already a 1min delay above

46 11 = -20 [5.0] don't want compressor to disable when heater enables!

46 13 = -5.0 [5.0] I only want immersion to boost heating when it gets really cold, below -5degC

46 14 = 2.0 [5.0] and switch off when outdoor temp rises to -3degC

46 20 = 3 [0] this enables the immersion heater to boost defrost function & be a second heat source in really cold weather.

46 23 = 38.0 [24.0] set higher than default, as I want the heater to come on 1m after defrost start, by which time the LWT is falling and soon reaches 38degC. If it doesn't energise until 24degC it's not really of any benefit.

@allyfish 

That's fantastic, thanks for that. I'll just need to check the wiring now but hopefully I'll have some months before the temperatures get that low again.....

Oh God. 

I don’t know if I have done something to my Grant controller. 

I held in the buttons to check LWT and parameters earlier and now when I do it it doesn’t seem to work. Just goes to resetting the date and time. 

perhaps I am cracking up.

Oh God. 

I don’t know if I have done something to my Grant controller. 

I held in the buttons to check LWT and parameters earlier and now when I do it it doesn’t seem to work. Just goes to resetting the date and time. 

perhaps I am cracking up.

and when I press the Return only button it just beeps and does nothing else. 😞 

Posted by: @marvinator80

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Oh God. 

I don’t know if I have done something to my Grant controller. 

I held in the buttons to check LWT and parameters earlier and now when I do it it doesn’t seem to work. Just goes to resetting the date and time. 

perhaps I am cracking up.

and when I press the Return only button it just beeps and does nothing else. 😞 

Go on google (or other) and find and download a Chofu R32 installation manual. Everything you need to know will be in there.

@marvinator80

Have you tried powering it down, counting to 10 and switching back on?

@derek-m not yet. 

will try that.

@johnmo 

thanks john, I have the manual in front of me.

@derek-m it worked. Thank you 🙏

Posted by: @marvinator80

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@derek-m it worked. Thank you 🙏

You should always try the 'Universal' reset first if possible.

Unfortunately poorly written software can sometimes get its 'knickers in a twist' when buttons are pressed in the wrong sequence, rather than issuing the message 'what on Earth are you doing Dumbo'?