@editor My LL's stance is that if Vaillant and the installers say all is 'ok' then I should just get on with it as I am not an expert but a lowly tenant and they have now met their 'legal obligations' in getting the leaks fixed. Obviously this definition of 'ok' is a very surface level and shallow one. Noone actually sticks around long enough to see what I mean about the UFH and other issues. All is not ok in my eyes due to the observations I have made about my UFH and meters etc. and general running of the system, heat loss calc and bills. It's all getting very 'political'. My LL has purchasing power, so I'm reliant on the integrity of others to help me. I've begun a written complaint as I have been forced to do this without any assistance from them but it's not easy as obviously I have to refer to many documents etc., and I am quite unwell at the moment which the stress of this situation is making worse. I also care for my son so time and energy  is in short supply. I'm currently working on a time-line of events and honestly it is quite shocking to see it all in black and white and the extent of the problems since last August. As I'm not that happy with my LL's handling of the situation I don't envisage I will get very far with them, even though I try to be constructive and factual always. I am generally met with, at best, defensiveness.

@batalto True, but it's risky and I just cannot do it. I'm left having to challenge this state of affairs the hard way.

@saz I would go into the settings you want to change and make a note of them. Then start tweaking. Worst case, you can always reset everything back to how it was. However its coming to a bad time of year for all this due to the warmer weather.

@batalto I think colder weather is on it's way but generally yes I see what you mean but I really would like to trial weather comp. My only option is to pour through the manuals and continue to request details of certain settings (as no one ever writes them down for tenants) and then that certain settings be changed by the contracted person. Vaillant renewables technical department are very helpful in enabling me to understand certain things but they have no power in this situation to get the changes made and neither do I. It's just all so wrong.

Manufacturer's response to my query today was that they now say that the most efficient method of running the heating is with the heat curve enabled but they would need the specific design temp for the underfloor in mind at a given outside temp. I have this info so why I wasn't just asked this last week I'll never know. They said the next best option was setting a 'fixed value' to allow the system to function and provide with property with heat regardless of system design. Just hope the person visiting next to finish flushing out the system will set this up now without a fuss. It's so ruddy frustrating as it's not as if it's complicated to do. I'm sure all this is within the basic screen of other manufacturer's heatpumps, like the Ecodan? Can anyone here advise?

@saz just give them any old temperature, as long as you can manually adjust to tweak who cares what they give you

I suspect it is very common for installers to avoid using weather compensation, and instead set a constant high flow temperature.  It makes for a quicker install where the customer will initially be happy as radiators are warm, it's how gas boilers are usually configured, it's unfortunately not the most efficient way to run an ashp.  I'm guessing it might need a few visits by a "competent person"  (Vaillant terminology for the person who uses installer mode) to perfectly setup weather compensation, and you would want a correctly functioning system before you even try. 

Nb: For UFH alone you might not bother with weather comp, as it's such an efficient emitter that the flow temp can be set low (<35C), and the efficiency improvement from WC would be minimal.

@Saz

I understand that there are underfloor heating downstairs, and radiators upstairs.  I'm not too sure how these are then plumbed, generally UFH doesn't want a high temperature, while rads do.  Can you tell what temp the heatpump is set to, and can you tell if it's heating rads and UFH together, or at different times and temperatures, as they are different "zones" which the sensocomfort seems to handle?

Don't let it get to you too much, nicer weather is on the way.

@robl Hi, thanks for replying, re the heat curve I was in contact with Vaillant today about this. The actual curve may have to be a compromise I think between what is best for rads and the UFH? although I do have quite large Stelrad K2s so they should be able to manage a lowish flow temp. I agree about UFH working most efficiently at lower temps. The heating is plumbed in as per the attached photos, via a buffer and there is no mixer on the UFH. It kinda bugs me a bit that installers make these assumptions about people's expectations for rads being hot as most people if it were explained in advance that the rads will not get as hot and why, then most people would accept it imho. I would like to be able to adjust the curve myself whilst trialling it to find the sweet spot of a comfortable indoor temp which might dispace the curve up a bit but I doubt I'll be afforded that 'luxury'.

 I think originally the pump used some kind of higher target temp for the heating not visible on the basic menu. The fixed value temp might be problematic going forward unless I could change it if I hit issues. Sounds like it's a compromise between original set up and weather comp but might compromise effciency also at certain times. The only thing that may be a concern for me re weather comp is that the Sensocomfort is in the hallway near the front door. There isn't generally that much in the way of solar gain, the pump itself is in a shady bit of the garden which is NE facing though.

I do have third party controls at the moment, I can set different times and temps if I wanted to for UFH or just leave it on a manual setback etc. and adjust. I know the most important thing is not to let the facbric of the building get too cold. The UFH isn't zoned though so it is difficult to get comfortable in one room without being uncomfortable in another. I'm thinking about asking for a some kind of valve to be put on the lounge loop and be wired into it's own receiver etc. as that isn't such a big job according to Wavin. The rads have two third party controls (just left over throw backs from adjustments over the years) and I can set times if I wanted to but not different temps which is a pain if I wanted to increase it first thing from the setback to heat the upstairs as I would have to manually adjust the old honeywell. I think I was supposed to have a Heatmiser fitted. There are TMVs on most of the rads except the one on the landing.

I forgot to mention that of course hot water takes priority.

@saz Wavin not drowning ? I do hope you get this sorted soon !

Well I have asked my LL to ask the people coming out to move the strainer to set up weather compensation so I am just waiting for a date now. The other issues I'll have to take through the complaints process which I am still working on.

Hi Saz, I recently had a problem with my heat pump failing but the installer had ceased trading. I was able to use my home insurance legal cover to get legal advice which enabled me to get the manufacturer to undertake the repair work. Have you asked your home insurance company if legal help is available?

If the installers were formally approved by the manufacturer then the manufacturer could have a vicarious liability for the installation work being undertaken correctly. They could then either undertake the works themselves or arrange for a 'competent' company to undertake the remedial works at their expense. The manufacturer may not want any bad publicity so mentioning that you intend to go to say Rip Off Britain with your problem may prompt a 'goodwill gesture' to get the remedial work done.