SimonD

yes, Opentherm does work in reality, but like all things heating, it depends on the boiler and or controller implementation as well as the heating system overall. The Opentherm protocol specifies a certain amount of information to be available but quite a bit of it is optional. Boiler cycling again depends on the setup. I'just installed Opentherm on an Ideal Vogue Max 18kW system boiler. House has a calculated heat loss of 7.35kW and the size of boiler was selected for DHW reheat times. The controller has a default minimum flow temperature of 45 C on opentherm. At this temp, even on a fairly cold day like today, the boiler will short cycle, and even worse with minimum flow temp set to 40C, which is what I set it to first. As soon as I increased this to 50, with a 55C max flow temp, the boiler ran constantly for well over an hour, with an almost constant return temp of 39.5C, increasing and then maintaining room temp nicely. On another recent install with a Viessmann 100-W into a very large, very old place with a very old heating system, I had to set the max flow temp to 80C and minimum at 45C. With Opentherm the boiler would run at 80 to get towards target but then ramp down as it got closer, so when I checked, it had dialled back to 53C to maintain temp at setpoint. It certainly can be used with UFH and rads. I work mainly with gas systems so always use mixers with ufh. In terms of controls, I like EPH because I have access to set max/min flow temps together with dhw temperature and its also possible to run pdhw on an s-plan system with these controls. I've even done this succesfully with Worcester boilers using the Nefit opentherm ems converter. Savings wise, research suggests between 10-15% although Tado in Germany has at some point suggested 25% iirc. Whilst it is two way, when I've had discussions with Viessmann technical when fault finding control problems, they confirm that the boiler becomes slave to opentherm and just passes info to the controller. However, the boiler doesn't necessarily pass all info across and will continue to manage some aspects like pump modulation relative to fan speeds etc. These will be managed by the boiler when it is simply responding to Opentherm's instruction for flow temp. HTH.

Yes, I saw that. Good modification you made. Something I warn all my customers about when they buy them but most don't listen.

You would have thought since we moved over to metric over 40 years ago but go onto sites like screwfix and they're all listed in BTU. One of my suppliers and radiator manufacturer recently republished their catalogue in BTU changing it from kW - I phoned the manufacturer up to ask what was going on and they replied as if I had gone mad! So I asked them what unit is used to complete heat loss calcs and they still were blank. It's just bonkers....

Yes, that's pretty much what seems to happen and thus no heat distribution either. The 38CDi classic should theoretically be able to run 40/30 flow and return, so I think there is a control issue. Would be interesting to test the system on relay control only and then set flow temp at boiler with system all open.

In my conversions, the nefit opentherm ems converter works well, but when boilers are more closely matched to heat loss. The Evohome system may be a problem here too. In this regard, I have to apologise to both @PeterW and @Nickfromwales because I now agree with them that it isn't great - well actually it's shite, especially for the price. I've seen problems, and have one installation I'm dealing with where it also has the tendency to short cycle the boiler under certain circumstances and its temperature management of the house is rubbish. I'm about to throw it in the bin and use EPH controls that will support proper pdhw and opentherm too. At least with EPH you've got access to the Opentherm configuration settings, unlike Evohome which likes to hide everything away. Do keep in mind that some boilers may not like running at low flow temperatures, which means that settling for 65 degrees if that is the minimum you've found the boiler to happily run at. I've found a few where this is the case because of the boiler and system design. As long as you're getting a low enough return temps, try it out for a while to see what happens. As a note currently I have exactly this problem with an Ideal Vogue max that will not run below 55 flow Temp without short cycling. With your tall rads, it's worth also double checking that they do indeed have a 20degree drop - I've come across many that due to their design can't be properly balanced because flow & returns short circuit. And this in turn plays havoc with the boiler. So a few things to ponder

So just the throw in a curve ball, in our last place we lived in, which was an old cottage the roof slates, which were beautiful old welsh slates btw, and had last been intalled as far back as the 1970s were laid way below the recommended minimum slope for slate. Not only that, when I took them up I found they had nowhere near the minimum lap either. The only leaks we encountered came from a flat roof area and poor detailing of this. Like others have recommended, I'd suggest having someone properly investigate the damp being experienced as it may well be a detailing issue that can be remediated without reroofing. Even if you don't think its down to the portion of the roof below the downpipe it's amazing how far water can track and the length of time it takes to do this and then build up to a problem. The other thing to keep in mind is the manufacturers given minimum slope will always have a generous margin in their favour. Just some thoughts.

As @ProDave says the standard off the shelf boards from BMs and most TMs is usually 2.44 x 1.22m unless you order in specifically 2.4 x 1.2. Although often assumed this is just a remnant of imperial measures, it's a function of being able to square off and remove the factory edge from things like sheets of plywood as they're rarely square or in good condition. I had a carpenter in recently to do some work for me and he had never heard of trimming and squaring up plywood sheets when I told him to make sure it was done. Only when doing so did he realise how out of square they were - which would have ruined the finish. Additionally, are you using 4 x 2 carcassing which is regularised or are you using 4 x 2 cls? The finished sizes of these are different! Personally, I just trim the sheets and studs where needed - the losses are marginal on 2.4 cls. Joined up thinking all this stuff does not represent 🤔

The leak is on the return connection of your central heating. This fitting is the isolator and boiler drain down point. To isolate this you turn the valve which sticks out the bottom of the connection. You also need to isolate the flow side. You then need to depressurise the boiler, drain it down and then probably just replace the fibre washer. However, even though this connection is outside the boiler, it is part of it and there's no telling if there's more of a problem inside. Get a gas safe registered person in to have a look and repair it as they may have to order more parts too. It's not unknown for those valves to need replacing entirely every so often.

Is that a drywall specific shadow gap bead or a plastet skim one? Ive come across the Trim-tex stuff when considering finishes earlier in out build. Apparently made specifically for drywall. https://www.profilestore.co.uk/c/drywall-bead/trim-tex/shadow-gap-beads

Yes, indeed. I've only ever managed bits of all those, maybe that's my problem...

Quite difficult to tell not standing infront of the boiler, but has anyone checked the condensate trap and drain? You can get a very similar sound on ignition if it's blocked and there's condensate backed up into the hex. You probably also mean mBar rather than mV. If gas pressure is too high you will see larger flames on a hob - how much larger at 27-28mBar is the question. Water gauges are about as accurate as you can get as long as there isn't a kink of obstruction on the gauge/hoses. A digital gauge is very accurate too as long as it has been calibrated as it should be annually. I use a digital gauge all the time and it's spot on, and the Network provider has never questioned my measurement when I call for a replacement regulator because of either low or high supply pressure. What were the measurements after replacing the regulator? As that should have been tested given the questions.

So yesterday I had a busy day dot and dabbing and thanks to the guy on On the Trowel Youtube channe, I skimmed my first ever walls as I need to get this room finished in the next week or so to give my younger son a bedroom - it was supposed to be in September. The wall was straight, plumb and the plastering was not a halloween horror show - just a few minor imperfections. I'm most pleased about the clean top corner to the primed ceiling:

I'm the east side, but Salisbury is still about 1.5 hours away. Thanks for the offer though, I'll check out my local suggestions and then ping you a message if needed!

Ah yes, thanks. I've investigated only to find that this appears to be the case. Where two cracks they're along the lines of a cut down board that only spans 600mm so it's only on two half studs. No wonder it's cracked around the joints. Now I have to figure out what to do about it. Just fixing the cracks is going to do the job really. Do I take the drastic action to cut this out, make a bigger whole and reboard to span several studs? It's a big wall 3.1m high by 7.4m long so not really practical to do the whole thing. Studding is pretty spot on as I did all that myself and its been in a long time so perfectly acclimatised to the house now. Yes, the third crack is at a joint that has missed the stud - thankfully one side of the wall is open so I can fix this easily!

Further to my earlier post I'm trying to understand why I've experienced cracking in the skim on new plasterboard on stud walls. I've had a look and it appears that skrim tape has been used at these joints. Can someone shed some light on other reasons this might happen? And is it fairly common for cracks to appear in new plasterwork as snagging?

Should have done a smaller project first! This too. That would have been ideal for where we are. I would also have appreciated finding BH a bit earlier, as that could have saved me a whole load of headaches. It didn't find this place until I was ordering my windows!

Thanks both. I might tap you for those details to see if they'll travel to me. I'm just the other side of Bath so some won't travel to me from Bristol as it can be a right PITA. A customer of mine has suggested I contact a friend of theirs who knows a few of the right people in the area so I'll try that first.

Yes 🙁

I'm not sure, it looks like there is skrim as I can just see a bit of it where it's been finished poorly at the bottom. If it is skrimmed, what else would cause the cracking?

Yeah, you're right. He did a couple of walls when I was there which seemed fine and I've clearly made the mistake of thinking I could then leave him to it. Clearly not, but it's a lesson in staying there to supervise all the time. Thanks, but I'm about double that time if not more! I'll go on another search.

The plasterer did it with one other person helping him, but mainly him. They work together and the other person was also boarding up the stud walls which the plasterer then skimmed. I've now found a number of cracks on the skimmed stud walls too. This is a picture of one wall. I can run my hand across the surface and feel the texture shown by the photo. Below are photos showing the undulation of the walls. I already spray painted one of the boy's rooms where quite a bit of the uneven surface and roughness showed up when painted and the undulation of the dot and dab walls showed up when fitting the coving. Generally finish is pretty poor in corners and around door frame etc. with loads of snots I'll have to remove to fit the skirting plumb: Dot and dab waves: High spot: Timeline 1.mp4 And now cracks in stud walls:

TLDR; what should a good skim finish look and feel like? Story below: So, sadly the plasterer recommended to me has turned out to be a liability. Had him in to do some work in the house and while my wife was there, I stupidly allowed the work to go ahead while I was away as my wife was in a hurry to get it done. I returned home to find the wonkiest poorly finished reveals ever, which they came to remove and then re-finish. However, in another room, as I was priming the plaster for painting I found a vertical crack on one of the dot & dab walls. Plasterer suggested drilling and filling behind the crack with foam and he would come a re-scim the wall to make good. I then inspected the work in more detail only to find loads of flex at the bottom of the board. Alarm bells started ringing so I remove the dot & dab from the wall to find that there were no beads along the long of short edges of the boards and the crack was down to movement along the long edge - in some places the dabs were as far as 400mm apart with the join in the middle of this gap. I've also found that another dot & dab wall is out of plumb and wavy along the length of the wall, so no straight edge used there. I've painted one room to find the plaster finish in there to be below par and plaster mess left everywhere so this guy isn't coming back to do anything else. I'm looking at the other areas he's skimmed and wondering what I should be seeing to determine the quality of finish. Rubbing my hands on the wall there are quite a lot of areas where the plaster feels like rough sandpaper. I can unfortunately also feel quite a lot of undulation of the plaster and there are some obvious full height lines of high spots at a few of the joins. So in short, what is considered a good enough skim finish in the trade please?

I'm not quite sure how I did it either. I'm sure there's a repayment lined up somewhere! My oldest son loves the mountains, so we're off to the wilderness of northern Sweden for a while, then mainly to Austria to explore there for the climbing, but as we're meandering, we'll be visiting France, Switzerland and Germany, possible nip over the Norway from Sweden too. Desparately need to finish packing, meanwhile I've got some backboxes and 1st fix cabling to do to that the bloody electricians 'forgot' so the plasterer can come in to finish boarding up and plaster a few rooms while I'm away - hard work this malarky

I think you're working too hard. I'm now off to take my son around Europe for 2 months. My wife's not too pleased as she's got to stay home and work coz she's an employee.....

It's possible. I was insured through Towergate for 2 years and now through Howden Insurance.