SimonD

Details are all in this thread, but as per my earlier comments about the Vogue Max, you won't find this arrangement detailed within the Logic manual either, but the Logic has an SL2.

@Radian, I'm looking at this with interest. You're not the only one to find a glitch with Vaillant modulation and anti-cycling - a discussion you may have already come across http://vaillantcyclingproblem.blogspot.com/2012/01/anti-cycling-mode-and-d2-parameter.html. There is clearly a link between the flow & return delta, but I'm interested to understand the size of your buffer and volume of ufh system. It would also be interesting to know actual room temp, plus the time points of motorised valve on/off switching for ch. How have you set up the valves? E.g. when calling for heat does your system provide heat to both ufh/hw and ch, or do you swtich between the two?

This isn't really a research paper and in my view it's unfortunately flawed both in its assumptions and conclusions. I've critiqued this paper on one of the other forums and suggested how dissapointing it is to see such a poor quality publication from an organisation that really should know better. It clearly needs to do its research properly, particularly around natural ventilation strategies. It reads more like an industry sponsored paper trying to sell additional tech.... What it actually needs to do is differentiate between building fabric design as well as geographic local and local climate in order to come to more a more reliable conclusion. I do think MVHR has its place, but I think it's important to position ventilation in terms of whole house design and function, which it rarely is. If you've got a house/building that has been built for high levels of airtightness but uses non-moisture buffering materials as part of its fabric, then MVHR is most likely the only option due to the ventilation requirements such a design requires. This is because the greatest burden of mechanical ventilation is down to the removal of moisture as opposed to air quality. On the other hand, if the fabric of the building is designed to be fully moisture buffering, hygroscopic, and vapour permeable, this can reduce peak internal relative humidity by as much as 25% which massively reduces ventilation requirements and therefore properly designed natural ventilation strategies are both effective and energy efficient. As you said earlier though, the op has multiple issues fundamentally caused by the fabric and lack of ventilation all which lends itself to some kind of MVHR , although with the single room options, I'd be concerned that they don't provide sufficient flow and movement through the whole house. I'll await the incoming now....😁

Yes, Opentherm does work and I'm sure that the Drayton wiser system will work providing it's installed correctly

I think that, as @SteamyTea has pointed out, the radiators effectiveness at heating a room is more down to convective currents that radiation. A wooden shelf above a radiator may not hamper that at all. In Sweden, it's a very common design element in houses where the window sill is extended (or cantilevered) out over the top of the radiators installed under windows. Provides some useful space, usually for house plants. Some of these are slotted which can be a nice effect.

This is the kind of argument that comes from the nuclear gaslighting sector, with very little understanding of the reality of nuclear, especially both the current and future waste problem. Here's an amusing video looking at the US situation alone- Otherwise perhaps this, which interestingly deals with the similar false argument that solar is somehow worse from a recycling perspective than nuclear: https://www.scientistswarning.org/2020/06/04/nuclear-power-a-risk-analysis/

Still isn't. Nuclear costing only includes 60 years of dealing with the waste, so yet another energy technology that will leave a horrible and expensive mess for many, many future generations, all for the sake of us not facing up to the real problem of how much energy we consume compared to what is actually sustainable.

I'd argue that this doesn't demonstrate that it's what people want, merely that it's the only choice they've got. Price is a another question but looking at the profits of the large developers, the margins are good and people are only paying that price due to restricted supply. I don't think it's in developers' interests to look at future needs, rather to bank the money they can now and look forward to another sale tomorrow.

The Vogue MIs don't cover the ins and outs of using SL1 & SL2. All you need for SL2 is a switched live from your wiring centre & programmer to the boiler SL2 IN when the cylinder calls for heat so it can be as dumb as it needs to be. The bit that does the modulation is the room stat which is what gets connected to the opentherm on the boiler. SL1 is then just bridged between L & IN at the boiler so there's no switched live to SL IN on the boiler from the programmer/room stat as this is managed through opentherm. If you were to upgrade to the T6R you wouldn't get any particular benefit from this perspective because as soon as you wire it up to opentherm the heating switched live connections are automatically disabled on the receiver (this permits the installation of the receiver for dumb on/off ch control using switched live, or load compensation through opentherm - the disabling of the switched live when opentherm is connected ensures you can't double connect to the boiler and confuse things).

Interesting publication about the effects of retrofit insulation, which, as ever, points towards a mix of interventions as well as behaviour. https://www.cam.ac.uk/research/news/insulation-only-provides-short-term-reduction-in-household-gas-consumption-study-of-uk-housing

Yes I'm aware of tado and aware of the reversal in decision to bring it back, even if messily. Every other controller I install has a clear ERP label that tells me what I'm installing. The Honeywell T6 is ERP class V which is a modulating control using opentherm. Ideal Halo products are class VI, again modulating using opentherm. I'm interested to hear who else you're claiming has degraded opentherm to on/off?

This is simply not correct. In my experience, it's often not the controllers that are at fault, it's how they are installed. When choosing a controller it's important to check the ERP rating of the controller as the combined controller and boiler ratings give the overall ERP of the boiler installation according to Part L. Below is a good explanation of the ERP classes taken from https://phpionline.co.uk/feature-articles/erp-control-classes/. Class I On/off Room Thermostat: A room thermostat that controls the on/off operation of a heater. Performance parameters, including switching differential and room temperature control accuracy are determined by the thermostat’s mechanical construction. Package/system space heating uplift = 1% Class II Weather compensator control, for use with modulating heaters: A heater flow temperature control that varies the set point of the flow temperature of water leaving the heater dependent upon prevailing outside temperature and selected weather compensation curve. Control is achieved by modulating the output of the heater. Package/system space heating uplift = 2% Class III Weather compensator control, for use with on/off output heaters: A heater flow temperature control that varies the set point of the flow temperature of water leaving the heater dependent upon prevailing outside temperature and selected weather compensation curve. Heater flow temperature is varied by controlling the on/off operation of the heater. Package/system space heating uplift = 1.5% Class IV TPI room thermostat, for use with on/off output heaters: An electronic room thermostat that controls both thermostat cycle rate and in-cycle on/off ratio of the heater proportional to room temperature. TPI control strategy reduces mean water temperature, improves room temperature control accuracy and enhances system efficiency. Package/system space heating uplift = 2% Class V Modulating room thermostat, for use with modulating heaters: An electronic room thermostat that varies the flow temperature of the water leaving the heater dependent upon measured room temperature deviation from room thermostat set point. Control is achieved by modulating the output of the heater. Package/system space heating uplift = 3% Class VI Weather compensator and room sensor, for use with modulating heaters: A heater flow temperature control that varies the flow temperature of water leaving the heater dependent upon prevailing outside temperature and selected weather compensation curve. A room temperature sensor monitors room temperature and adjusts the compensation curve parallel displacement to improve room comfort. Control is achieved by modulating the output of the heater. Package/system space heating uplift = 4% Class VII Weather compensator and room sensor, for use with on/off output heaters: A heater flow temperature control that varies the flow temperature of water leaving the heater dependent upon prevailing outside temperature and adjusts the compensation curve parallel displacement to improve room comfort. Heater flow temperature is varied by controlling the on/off operation of the heater. Package/system space heating uplift = 3.5% Class VIII Multi-sensor room temperature control, for use with modulating heaters: An electronic control, equipped with three or more room sensors that varies the flow temperature of the water leaving the heater dependent upon the aggregated measured room temperature deviation from room sensor set points. Control is achieved by modulating the output of the heater. Package/system space heating uplift = 5%

I lean towards the Vogue Max as my preference but have done a few Logic Max installs now too. I've installed some T6Rs with heat & hot water so if these have the same wiring as the earlier T6, then is fairly straight forwards. In the receiver box, wire up your heating to opentherm on the boiler (bridging the SL1 connection) and then wire the hot water switched live to SL2 on the boiler via the junction box, cylinder stat and motorized valves. I prefer using 2-port diverter valves, so have a normally closed on the dhw side and normally open on the ch side that is wired to the normally closed valves switched live so that it closes when the dhw diverter opens. Intergas are good boilers but if you look at the minimum output on modulation the Ideal is slightly better, except for the 40kW intergas system boiler. By this I'm assuming you're intending to have everything on constantly and rely entirely on the flow temperature set point to manage room temperatures? The T6 controller will provide you with some additional control, especially if you don't want your heating on all the time. I also wonder whether this setup provides less overall control of the system than load compensation using programmers/room stat/ and opentherm. Ideal's own installation manual gives an ERP of 2% with weather comp on its own and 4% used in combination with a programmer.

I think Part L has been done really badly. There is a separate section with the AD that details what needs to be done for boiler only replacements. I've seen there's also confusion about what impact Part L has on boiler servicing requirements. I'm completing my Part L energy efficiency and low temperature system design soon for MCS registration so I wonder whether this training will help to decipher more of the code!

My experience is so far is mixed. With the new Part L we're technically only required to design to 55C flow temps where there is a new heating system installation. When it comes to replacing a boiler, it's about ensuring that the new one doesn't perform any worse than the one you're replacing and then that controls are installed that provide either weather/load compensation, or automisation/optomisation, or flue gas heat recovery. There is also a requirement that if you install a new boiler you should also install trvs if there aren't any. The part that does get a bit messy is where you rightly point out that in order to make the system efficient, you ideally need different dhw and ch flow temps. In my experience in many instances it's the boiler rather than the controller that causes the problem, simply because it cannot deal with this difference - it beggars belief the number of installers around me chucking in a certain model Worcester Bosch boiler despite this problem, for example. However, you can find the ones that do, even if the manufacturers might not explicitly tell you about this. I've personally gravitated towards Ideal boilers because they have a separate switched live for dhw that gives a flow temp of up to 80C and a normal switched live that can be set to 55C or lower for CH. Even better, I can install an opentherm controller to the boiler to modulate the ch but still use the 80C sl2 for hot water (it's also possible on some models to set a max boiler water temp to bring down the dhw to whatever you like, if you want). What I've been doing with system and heat only installations is reconfiguring to PDHW using a combination of normally open and normally closed diverter valves that make this system work properly, even in multi-zone installations - basically the normally open valve is used on the ch side and normally closed on dhw and when the cylinder stat calls for dhw heat, it opens the normally closed at the same to as closing the normally open. For controllers I've been using either the Ideal own systems (Ideal Heat & System Halo does support priority hot water, which is good) or Honeywell, but have done and will be doing installs using Nest/Hive/Tado, usually specifically down to customer specifically asking for them. With Tado, I'm still very unhappy with how they've dealt with Opentherm here in the Uk and when I explained what was needed now - a wired unit + wireless extension, a recent customer wasn't too happy either, asking me if I couldn't just get an EU version for them.... Problem is that most customers have no idea how each individual controller works and it's difficult even as an installer to know these things properly. More widely it's a total mess, a lot of installers are ignoring these new controller requirements so they're quite happy to bung in a new boiler and wire it up to existing controls and don't seem to know about modulation. I suspect it's the same for new whole system installations where it'll be rule of thumb. From a customer perspective, feedback has been quite interesting. Only very recently are they asking about flow temperatures and how to best set them up, so the message is starting to get out there. I've just read this. I understand the rationale behind the idea but I think they've missed a number of critical elements and is a bit misleading. For example, you won't get a replacement boiler in just 2-3 days as there's a serious shortage of installers across the whole country, and according to recent industry research only about 1/3 of existing gas engineers are planning to train to do heatpumps, leaving us in a very dire situation for resources. Yes, the boilers are most often distress decisions, but I don't think the library idea necessarily works. If a customer is going to be asked to pay £1500 for the installation of a new boiler that is expected to last for 10 years, it's a bit steep to ask them to front this cost for a leased boiler, for potentially a year or so, something that will impact poorer purchasers much more. I also think they've got to reconsider the reality of making the home heatpump ready. In many instances I think it'll take a good 10 years for this to happen and by then they're better off just purchasing a replacement boiler (from a convenience, cost and function perspective). The one thing that doesn't get much air time, but has been making the rounds much more in the industry press is the hybrid heatpump/boiler, contained within a casing about the same size as your typical boiler. As a transitional idea, this is making more and more sense to me, simply because of the problems we've got with our housing stock and existing boiler install base of combis. It would also help in respect of making the boiler much better at modulating output through the year.

In this instance I believe that the flowchart is referring to the room thermostat set point rather than the flow temperature set point. Ideally you want to see the programmer/boiler modulating before this set point is reached. (Interestingly on my Honeywell Evohome setup it tells me the percentage modulation compared to the boiler flow set point, which as you say will vary according to how close the room is to its set point and weather conditions) It seems, however, that the flow chart is a troubleshooting one that looks at diagnosing problems with modulating or cycling of the boiler due to flow rate issues within the heating system? I've seen this recently where low flow rate causes a too high flow/return temp differential (e.g. more than 38C and thus eventually throws a fault at the boiler), or that flow temp rises too fast so the boiler has to switch off (flow temp rises above the flow temp set point and too quickly), again due to low flow rates. With the new building regs I reckon there's going to be far more head scratching going on with Delta T/Flow Rates/Modulation/Cycling - in the real world it's turning out to be a time consuming process to get right! I'm finding quite a few issues setting all this up with new boiler installations on existing heating systems. Does your boiler have a flow rate sensor and a way you can access this information? Then put in a phone call to Glow worm customer technical support and see if they can give you specific flow rate figures to work by (Sometimes they don't like giving out too much info mind you). Alternatively, there's a straightforward calc given by Grundfos: https://www.grundfos.com/sg/learn/research-and-insights/calculation-of-flow. Or there's the CIBSE Domestic Heating Design Guide that has a more detailed section on flow rates: https://www.cibse.org/knowledge-research/knowledge-portal/domestic-heating-design-guide-2021

I think you might be better off measuring up the gear and then ordering a replacement spur gear with pin holes from a bearing supplier or other industrial supplier. That way you'll most likely get the right diameter and maybe a better quality gear. You'll need to know the module: http://www.metrication.com/engineering/gears.html

Yup, I bought a load of gun grade airtightness foam, well only a pack of 6 thankfully, from a 'full priced' reputable online merchant only to find out the foam was to be out of date the week I purchased and received the stuff - I didn't check the cannisters until a few weeks later when I used them. I don't know how much we need to care about the use by date on these products but the foam wasn't ever quite right. With these products I now use suppliers who specialise in this stuff as I suspect they have the trade volume. Who knows?

The proper way is to have adhesive mortar and mechanical fixings. The mortar obviously has a role as an adhesive but it also evens out the substrate. The mortar also prevents convective air movement behind the ewi which can have a significant impact on performance. Depending on the brand the adhesive can be applied in a continuous cover, or as thicker beads around the back perimeter of the boards with some dollops in the centre. Question is whether if the builder didn't know this, is he up to the job? EWI detailing is important, round all the penetrations and at eaves and dpc level. Has this been designed, discussed and agreed? Do you have drawings or anything confirming the detailing?

I would tell them that you're going to put in a call to Gas Safe and ask an inspector to come out and have a look.

My first question is why not get a replacement casing? Has the person condeming the boiler checked availability and pricing as an option? On most boilers nowadays (at least 15-20 years) the casing is classed as part of the flue system and if there's a hole it means the boiler ain't room sealed any more, thus dangerous. I think there's generally some confusion about boilers types and systems here. Perhaps it's easier to think of the boiler as just the heat source and then separate the systems that use the heat. One system is the central heating, the other is domestic hot water and with domestic hot water there are two sides to the system - the heat input and the heat output. Both system and heat only boilers heat a defined body of water contained within a set of pipes that provide the heat input to the radiators and hot water cylinder. This heat input circuit can either be open vented or sealed. A heat only boiler is usually found on an open-vented system, but, using an external expansion vessel, can be sealed under some circumstances if deemed okay by the manufacturer. A system boiler is sealed as the system boiler has a built in expansion chamber. This circuit of water is, through diverter valves pump through either the hot water cylinder or the heat circuit, or both. The difference between the boiler types is due to what is included in the boiler and as correctly pointed out above a system boiler has pump and expansion valve, some have the automatic bypass fitted and so forth, so there's less additional stuff needed. With heat only you need to install a pump and bypass etc. separately. You then have the heat output of the hot water cylinder. On either of these boilers, there can be an unvented cylinder, which simply refers to the fact that the hot water is stored within the cylinder under mains pressure and is not vented to a F & E tank in the loft. This has no effect on the heating circuit of the boiler as it's kept entirely separate by using an 'indirect' cylinder. So overall, either/both the systems can be open-vented or unvented so it's important to differentiate between which particular side of the system is being referred to. Not necessarily. The external mains upgrade is required for the unvented cylinder to work as designed. You could actually install a system boiler and just remove the heating F & E and at the same time retain the gravity fed open vented hot water cylinder until you have the work done. Your minor risk with this is that the pressure within the heating system of the new system boiler might cause leaks in the old system - but I think that risk is probably fairly minor.

No I can't. The wired version is not the one I'm after, nor is it the one my customers are after. Why? Because so many existing wired thermostats are installed in really stupid places in the UK. I'm just doing an install in a Georgian townhouse. The thermostat is installed in the basement next to the hot water cylinder and existing boiler, a floor mounted old behemoth of a boiler. I just completed another installation in another Georgian town house where the wired thermostat was in the 1st floor landing. I did 2 services in newbuilds where the wired thermostats had been installed in the hallway only an couple of meters from the front door with no relation to the living spaces. The customers don't want to pay for rewiring of a thermostat to somewhere else. So Tado still doesn't do a wireless smart thermostat that does modulation unless you have a combi. Still a problem in my view. At the end of the day, this is the biggest problem - to educate the installer base to do a proper job. But then it doesn't just apply to Tado. I just fixed a Vaillant system where the previous installer had fitted two Vaillant controllers to try and get it working and the problem was merely the heat curve.... but I have to say that in both instances as also with the Honeywell Evohome the manuals are total and under crap - if the manufacturers took the time to produce proper information, the story might just be a tiny bit different. IMHO

I really liked my Festool HK85. It was a beast until I experienced the so called 3 year service included service from Festool. My experience from this was that they do the absolute minimum they can. My HK85 went back twice and the second time I was getting some pretty bad noises and vibration from the saw within a few weeks of receiving it back from them the first time. The second time it came back supposedly fixed but with smaller noises and vibration and very much not right - the cutting blade vibrates slight against the saw body when you start it up but apparently this is fine by them. Funnly enough, if you send the same product back after the 3 year service has expired they'll charge you for making the saw like new. After this experience, I won't be buying Festool again. I've found my Mafell to be very robust and if I was going to buy a cheaper saw I'd probably opt for the Bosch GKT 55 as it is essentially a Mafell with some differences.

Only on the combi model it appears. As for that video, it smacks of the type of company that makes my blood boil - removing functionality from a product without telling anybody in the market you're doing that? I personally only found out just before it was too late that they'd done this and no thanks to the company! It also suggests they have little clue about the market they're dealing with here in the UK. If there's not much uptake of a product, would you not sensibly investigate why and try to resolve the problem rather than dumb down the product to make it cheaper and at the same time claim the reduction in heating costs probably only realised by modulation? Also, there doesn't seem to be any understanding that they might need to communicate better to both customers and professionals doing the installation to understand the benefits of modulation. To me that video does very little to build any trust in the company even if the technology is fundamentally well designed - it still doesn't appear properly support modulation on all heating systems and boilers in the UK, and they haven't moved beyond Y and S plan.... IME lukewarm radiators are not the problem, it's being cold in the house.

I have those tracks too, mostly used with the Festool HK85 rather than the TS plunge version. I have the Mafell plunge saw which uses both the Festool tracks and the Mafell tracks. After 4 years of use I found the Festool tracks to be really robust apart from the splinter guard which always peels off. The biggest issue is aligning them even with the self-aligning connectors I bought. Always have to check with a straight edge, especially for 2nd fix and making cupboards/cabinets and then if you knock them while moving about...... Overall I'd have to say I prefer the Mafell track system, which I think Bosch also uses.