It’s the company or perso who specify that should be fine tuning the controller. Ideally that’s the installer too

Installing and commissioning is not work for plumbers I’m afraid. There are many pitfalls that won’t occur to them as many find out 

@alec-morrow The installer was a plumber I think but experienced with heatpumps but I could be wrong, he had an electrician working alongside him that their company contracted. I think many of the settings, like weather comp for instance the end-user should be shown how to set up themselves (and reverse if they so wish). Is that being naive and/or idealistic? I'm not talking about messing with any other settings. One of my neighbours for instance has an Ecodan and this is easy to set up for weather comp in comparison.

In viessmann the curve is a user parameter..vaillant almost

the only thing between you making changes and getting a desired out come is the instruction book!

it’s on the internet

@alec-morrow It's behind an access code (not rocket science to guess) but I am not 'allowed' to change it. I figure it could be a very simple task to do by just setting Circuit 1 to heating and not fixed value and then adjusting the heat curve and and possibly a few other basic settings. An outdoor temp sensor is already in situ. I'm just very frustrated that it's taken weeks to get someone out here to do this when Vaillant could have probably talked me through this over the phone, as they no doubt will do with the electrician when they are here as they are unfamiliar with these controls (which I discovered when they came out when the compressor blocked message was up)

glad you recognise the rot starts with the manufacturers…installers can be crap for a reason..

@alec-morrow I have actually mentioned this to Vaillant but I didn't get any comment on the fact that their controller design means a lack of simple control for the end-user as compared to other manufacturers.

@saz you won’t, they are just there to move equipment like washing machines 

in fairness as an installer I can tell you that if the install follows vaillant design principles based on German Standards the outcome is exceptional

the grief we have in the U.K. heating industry is made in the U.K., not much if any of the equipment is though, only grief is U.K. made

@alec-morrow How do the German Standards differ?

Very annoying is that Vaillant said to me, 'Why wasn't weather comp set up at install?' Well, I can hazard a few guesses at that one and yet one of their own engineers who came out recently was critical of it anyway and put a fixed value temp on the heating. So there is ZERO consistency regarding what should be happening even within the same company, let alone between different installers and repair guys.

german standards have mandate out door sensors on all heat generators since 1985. They don’t use on-off controls to control a heat pump and other pumps…all low voltage modulation of flow temperature.

there is no will at a policy level for this approach despite the benefit to consumers and reduced energy consumption. 

Its shameful and a disgrace… but hey a  unhappy heat pump customers don’t matter!

I'm beginning to see the wood for the trees now in my own situation. Forgive me if this is a stupid question but does having microbore on the rads (UFH set up correctly as far as I know) specifically affect wheather weather comp might work (as well as how the pump works in general without weather comp)? These houses were supposed to be designed for heat pumps 9 years ago but have microbore. 😏

Posted by: @saz

I'm beginning to see the wood for the trees now in my own situation. Forgive me if this is a stupid question but does having microbore on the rads (UFH set up correctly as far as I know) specifically affect wheather weather comp might work (as well as how the pump works in general without weather comp)? These houses were supposed to be designed for heat pumps 9 years ago but have microbore. 😏

It might. When the output flow temperature is low, as with a heat pump, you need the flow rate to be high.  If it isn't, the return flow, and therefore the average temp of your radiators, could end up too low.  So a weather compensated system, where the output flow tends to be low might struggle whereas a higher fixed flow might not.  But it all depends on whether the flow through your microbore pipes is sufficient.

A lot of ASHP installers won't touch microbore but some people run it successfully. I'm surprised a new complete system would be designed with microbore but then again one of the reasons for microbore was to cut costs.     

I can see the flow rates on the live monitor and have seen it go up to 860l/hr. I guess the only way I'm going to know is if I trial it? I'm wondering if that's why the Vaillant guy who recently visited wasn't keen on the weather comp idea and put a fixed value on it. He would obviosly have spotted the microbore. We were always told our old pumps weren't installed correctly but noone ever elaborated really (I wonder why? 😏) on 'various plumbing and electrical faults'. The manufacturer washed their hands of it all because of it. There were so many mods and tinkering in the end noone knew what was what, and various different repair people in and out over the years with different opinions etc. and conflicting ones. Even so this pump is still proving more expensive to run. You would think that as this was a new build 9 years ago it was the ideal opportunity to put the correct bore pipework in. Well that's not what happened. So we are stuck in a kind or wierd position of having very well insulated houses (allegedly because I'm wondering if corners were cut) and UFH, large Stelrad type rads etc. So not really a retrofit situation when it comes to replacement, but this house appears to have been treated as such (although 2 neighbours with replacements have been fortunate enough not to have high temp pumps).