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JSHarris last won the day on February 19

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About JSHarris

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    Wiltshire/Dorset Border

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  1. If Ventaxia don't offer a proper inlet filter, then I'm sure that one of the specialist filter companies could supply one. I bought five sets of custom made filters for our MVHR from Jasun Envirocare, who charged me around the same for five sets (ten filters) that the UK Genvex agent wanted to charge for one set of the branded filters. As far as I can see they are identical, folded paper filters in a card frame that fits tightly to the slots in the unit. They don't seem to be restrictive, unless they get very clogged up, but they do keep out pollen and dust, so ensuring that the heat exchanger core, fans etc all stay spotlessly clean.
  2. Graven Hill - Custom Build Site

    The fact remains that if the VAT legislation wasn't so obstructive, then this dodge wouldn't have been required. It would have been straightforward to put all the controls they wanted in place using a covenant, or similar mechanism, or they could even have amended the local plan to add a policy specifically for the site. The main issue is that it seems to have forced the use of less energy efficient foundation systems, unless the builders choose to try and get around that limitation at additional complexity and cost. The house footprint and design restrictions they wished to impose did not require them to go so far as to put in all the foundations. I was similarly constrained on our plot, by some very tight planning restrictions, and they included exactly where the house would be, what size of footprint would be allowed, even what the finishes were and the floor and ridge height were. However, I retained the freedom to use any build method I chose, as long as the external appearance, size and shape met the requirements. Had the VAT legislation been flexible enough to accommodate what was ultimately the government disposing of land for development, then none of this barking mad shenanigans would have been needed, and there could have been substantial cost savings for all involved.
  3. Graven Hill - Custom Build Site

    @Charles Ebden, I think it's worth looking at why Graven Hill had to put in place such a restrictive, and potentially expensive, solution for the self-build plots. The driver seems to have been inflexibility in the VAT legislation, which prevented the local authority from selling off plots VAT free. Normally building plots don't attract VAT, and neither does the house build itself, but in the case of Graven Hill there was a glitch that meant that all the self-build plots would have attracted VAT on the sale price. They got around this by using the "golden brick" dodge, but that both added restrictions and increased the price of the plots, but it was the only way they could come up with to avoid buyers having to pay VAT. If there had been a more sensible way around this, which would have needed a change in the VAT legislation, it would have been a very much better scheme, and would have cost far less both for the buyers and for the local authority. In many ways, what they've had to do is barking mad, but they seemingly had no other choice. I don't believe that the affordable housing there are self-builds, they are a traditional Housing Association development, just like any other.
  4. How do the insects get past the filters so they reach the core? Looking at ours, the filter frames are a pretty tight sliding fit in the case, with what look to be neoprene foam seals at either end to make sure they are sealed in place. The fresh air inlet filter is a pollen filter, so pretty fine. If insects are getting to the core, then it sounds as if there must be gaps somewhere around where the filters fit. Might be an idea to see if there's an easy way to get the filter to seal more effectively, and remove the problem. I suspect that mould spores are also getting in the same way, as they are around the same size. If the pollen filter is sealed and working properly, then it should also keep out mould spores and the like. As an example, a G4 filter will typically catch most particles over 10µ, and F7 filter will catch most particles over 1µ. The smallest spores are around 2µ, and some of the more potentially harmful ones, like aspergillus, are around 20µ, so if such a filter is well-sealed into the MVHR case it should be able to catch the majority of both spores and pollen particles.
  5. @PeterW, I really admire your ingenuity! I wish I'd thought of doing something similar, as using standard plumbing fittings allows a heck of a lot more freedom when trying to fit things in.
  6. Uni Lecturer's Strike

    The problem is that some, like me, started work with a defined career plan, that included having a lower than average salary for the job, being subject to a compulsory mobility clause that meant I could be moved anywhere in the world with 6 weeks notice, with the upside being retirement at 60 with an index linked pension that was 50% of my final salary. By the time that they started to introduce changes to the pension scheme, around 17 years ago, I was past the point where I could just change jobs and hope to have any sort of reasonable retirement income. If I were 45 years younger, starting out, then my priorities in seeking employment would be totally different, because of the changes in pension schemes and the more flexible employment patterns that prevail today. When I left uni I had four job interviews, one for a pharmaceutical company in High Wycombe, doing research on contraceptive drugs, one for British Aluminium at their research lab in Denham, one for Fulmer Research, doing research on novel applications of concrete and one for the Radiochemical Centre, Amersham, doing research into medical diagnostics using radioactive compounds. I was offered all four jobs. At that time, the Radiochemical Centre was a part of UKAEA, and was linked to the Scientific Civil Service in terms of pay and pension provision. I wanted to go and work for Fulmer Research, as I really liked the way their lab worked, and they offered the highest salary. My father (a banker) gave me a stiff talking to and explained to me that although the worst paid job I'd been offered (by a very long way) was working for UKAEA, the pension scheme was far better, the job security was pretty much guaranteed and there was an excellent career development path, so I should think long term, not short term, and accept the job with UKAEA. That's exactly what I did, and even when I found I hated working in chemistry and switched careers to work for the Scientific Civil Service (as it was then) working on defence-related research, I was still motivated by the long term job stability and the good pension. By the time I was 40, the job security had gone and the writing was on the wall for the pension scheme too, but thankfully the government chose to make the pension changes only to new employees, so although the past 10 or 12 years of my career were not as planned, I managed to take advantage of every opportunity going to just seek promotion, even into jobs I didn't much like, solely to push my salary up and so increase my pension.
  7. Uni Lecturer's Strike

    I'd be as upset. As it happens, around ten years before I retired my employer decided to change the pension scheme to a contributory one, and has since changed it again to a defined benefit scheme. However, the big difference is that they only made these changes for new employees, although they offered existing employees the "opportunity" to change if they wanted to. Finding out half way through your career that your pension is going be significantly reduced isn't on, IMHO, as many will have made long term financial plans based on the previous contracted terms. It's very true that for a lot of people their outgoings in retirement are much lower, but there is also the effect of no NI and reduced tax, which means that for a lot of people their actual retirement income is nothing like 50% of their working income. Right now, my actual after tax income is over 70% of the income I had when working, for example.
  8. Sunamp heat battery

    There are two different units,the Sunamp PV, which has a built in circulating pump and water heater to heat the batteries and the Sunamp Stack (and variations of it) that just have the heat batteries and some plumbing and control equipment, so they can be heated by hot water.
  9. My Nightmare Heating System

    I had much the same. I decided to fit a new kitchen, drove 60 miles up to Ayr to pick it up, then 60 miles back home again. The next day I discovered some hinges were missing for the doors, so had to drive back up to Ayr and back to pick them up, around 2 hours each way.
  10. My Nightmare Heating System

    When we lived in Dumfries and Galloway we either drove around 60 miles to Ayr to do a "big shop" or drove 60 miles to Dumfries. Most of the time it was quicker to get the Seacat over to Belfast and shop there...........
  11. My Nightmare Heating System

    Nice reliable internet data.......... I reckon a fair proportion of the information on the internet is just plain wrong, much of it repeated from other sources with zero fact checking. A bit like some news sites.
  12. Sunamp heat battery

    It's actually the phase change temperature, rather than the input temperature, in deg C. So PCM34 changes phase from liquid to solid, releasing heat at 34 deg C. Equally it changes phase from solid to liquid when heated to 34 deg C (actually a wee bit over). Same for PCM58, but at 58 deg C. The Sunamp PV uses PCM58, and the water temperature that comes out when it's running is pretty close to 58 deg C when it's got rid of it's residual stored heat. The heat batteries store heat in two ways in the Sunamp PV. One is by absorbing heat energy by changing the phase of the sodium acetate salt, the other is just heat stored conventionally by the heat capacity of the heat batteries. The total storage capacity initially, when the heat battery is still hot, is a bit higher than the phase change temperature. This means that when you draw hot water from one, initially the heat being drawn off is just that stored by the heat capacity of the heat batteries, then when it drops to 58 deg C, the salt starts to self-nucleate and change phase to a solid, releasing the heat from the phase change, plus a small amount of residual heat from the heat capacity of the material. This means there is a variation in heat storage capacity that is time dependent since the last charge for a few hours.
  13. My Nightmare Heating System

    I agree, definitely try to sell it, or if you cannot be bothered, then maybe someone here who lives nearby may offer to look at it, take some photos and list it for you. I'm certain it should fetch a decent price - might even pay for the work needed on the heating system.
  14. Concrete slump

    Sorry, haven't a clue, as it was all specced, signed off and installed by the same company, and there's nothing on any of the paperwork I have that gives that level of detail about the concrete spec. I'm not sure there are many who've done a DIY passive slab, which may well be why you're not getting answers.
  15. My Nightmare Heating System

    Shouldn't do, unless the system has been boiling for a long time and has vented off all the steam. Even then it should flush clean OK. AAVs are normal, as is a PRV to allow steam to blow off if they boil. Shouldn't happen normally, as they reach stagnation temperature and just sit there, assuming the controller is working.