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About woodman

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  • About Me
    Mechanical engineer now retired to a small village in North Yorkshire. Interested in all things renovation, energy saving, DIY, Hi Fi.
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    North Yorkshire

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  1. Hi Savage 87, good to share this stuff I didn't take any photos as I built the unit, howver I'll tke a shot of the finished item next time I'm in the loft. Not much to see though, as the whole thing is covred in rockwool insulation! The intake fan was originally set at aroud 25% trickle, it's nowup to about 35% trickle. Boost has always been 100% Unfortunately, I cannot easily adjust the fan settings for nightime, as the controls are mounted on the MVHR unit, in the loft. My electronics expertise does not extend to making an additional control unit, although i suppose I could re-mount the existing controls remotely.... The filter size link is a great resource, I had not consideed using a car filter. I've just looked up a couple, are they all US spec applications? I'm in the UK, but I guess most are global spec anyway. Did you use the tool to find a filter of the size you want, then do a seperate search to find a carbon filter, rather than particulate? I would have thought that car filters have a pretty high resistance- What filter size did you use, and what effect did it have on fan speed in your application?
  2. Hi all, I've fitted an F7 filter to my mvhr system, which uses a nuaire xbox95wh1 (very basic unit, but bought very cheaply, £350 as new, as an incorrectly specified installation) The whole thing has cost less than £100. Here are the key points of construction, results and next actions. I hope this is helpful. I'd also appreciate any further info you may have to assist with the next steps, as below. SYSTEM DESCRIPTION https://info.nuaire.co.uk/IandM/671686.pdf The system has 5 extract and 5 intake ducts, semi-rigid ducting, external vents being on the gable end of the house. THE PROBLEM To try to eliminate wood and coal smoke pulled in from my neighbour's woodburners and open chimneys. I firstly researched the commercially available units such as this: https://www.blauberg.co.uk/en/blauberg-cleanbox-nox-carbon-polution-pollen-indoor-air-quality-filter-box-for-heat-recovery-ventilation-systems and this https://www.airclean.co.uk/indoor-air-quality-filtration/indoor-air-quality-filter-system/ but they appeared to be vastly overpriced for what they actually are, so I decided to make my own, initially using a g3 and f7 filter, as here: ASSEMBLY G3 prefilter and F7 particulate bag filters used: https://www.addfiltration.co.uk/12x12x2-290x290x45mm-g3-grade-2-deep-dry-glass-panel-filter?search=g3 https://www.addfiltration.co.uk/12x12x12-287x287x300mm-4-pocket-12-deep-f7-grade-synthetic-bag-filter?search=f7 bag Total cost inc postage, around £20 I used an F7 bag filter rather than a panel filter to increase the interval between servicing. The enclosure itself was fabricated using tilebacker board, as it's robust, light. cheap, easily cut, and impervious to moisture. Much better than mild steel, plywood, MDF etc. https://www.jtatkinson.co.uk/catalog/product/view/id/11068/s/multi-pro-moistsure-tilebacker-s-e-1220x800x12mm/ cost, about £15 I used angle brackets to assemble the enclosure, which was then sealed with silicone sealant. Total cost about £10. Removable filter access panel was fixed using these, as I had some lying around https://www.powertoolsdirect.com/forgefix-cavity-wall-zinc-speed-plug-4-5-x-35mm-bag-10 150mm duct flanges from here, about £10 delivered https://easyhvac.co.uk/index.php?id_product=155&controller=product Total cost around £60. Significantly cheaper than the above, although it does not have an activated carbon stage yet I designed the enclosure to fit in the loft under the roof, so it's an interesting rhomboid shape. Ive also provided for inclusion of an activated carbon filter stage within the enclosure, should it be needed. I used f7 rather than F8 to keep the pressure loss within reasonable limits, my thinking being that I can replace the F7 bag with an F8 at minimal cost after seeing how the NuAire unit handles the pressure drop. I have removed the existing filter media from the MVHR intake filter, ensuring that the edges of the filter frame still have the original G3 media present to prevent internal leakage within the MVHR unit. RESULTS 1) The filter still allows some smell of smoke to penetrate, although to a significantly reduced degree than previously 2 ) OK Intake flow rate been achieved despite the increased F7 filter resistance, although as expected the intake fan speed had be increased to maintain airflow as before. The MVHR clogged filter warning has not been activated, therefor the system must be working within its design parameters, ie the fan is not seeing excessive load. 3) Increased intake fan speed has resulted in increased noise level. This noise level is still very low, but any further increase, say to accomodate f8 and/or carbon filter may become unnacceptable for sleeping NEXT ACTIONS 1) SMOKE/SMOKE ODOUR I may add an activated carbon filter, using media such as this: https://www.calgoncarbon.com/products/ap-4-60/ I'll make a tray with seive material in a an open frame. i've already included supports for such a frame in the MVHR enclosure I may also experiment with an F8 filter to see which solution gives the better result at the lowest pressure drop. AND/OR I may substitute the F7 for an F8 bag filter. Does anybody have any experience of the effectiveness or otherwise of F7/F8 for smoke particles? 2) NOISE The filter is fitted before the MVHR, so I may seperate the G3 and F7, and move the F7 filter stage to post MVHR, this will probably eliminate this noise issue, and allow for further fanspeed increase if necessary. I also wonder whether the MVHR fans are better at 'pushing' or 'pulling' the air. I'd appreciate any further info on this point if there are any experts out there 3) Further down the road, if the carbon and/or F8 filters prove to have to much resistance for the stndard Nuaire fan, I'm thinking that maybe an additional intake fan, seperately housed, immediately before the MVHR, would overcome this problem. I've not researched this as yet, so I have no idea how to specify such a thing to produce the appropriate pressure and flow at minimal energy consumptiion. I hope this is of use. Any info or comments you may have, especially on the fan'pushing vs pulling' aspect, or the implementation of an additional fan would be greatly appreciated
  3. Hi, I thought I'd share a significant insulation improvement I've made in my bungalow... It's a 1970's split level bungalow, with the living accomodation upstairs. Having thoroughly draughtpoofed, installed modern double glazing, new energy efficient doors, underfloor insulation, cavity wall insulation, removed all window reveal cold brdges and insulated them, 400mm of loft insulation and MVHR, I expected the place to be really warm. But I always detected a sort of cold downdraught from the ceiling. Very strange. I recently had the roof tiles and membrane replaced. Whilst the old roof was off, the likely culprit became visible. As its a pitched roof, the inner wall is of course taller than the outer, this taking the weight of the roof trusses. So the top 400mm of inner wall leaf comprises effectively a single skin, uninsulated block wall, in what must be the worst position possible, all around the top of every external wall, where the internal temperature will be highest, therefore leading to max heat loss. So, while the roof was off, I insulaed this vertical section with rockwool, leaving room for ventilation between the new membrane and insulation. The result? An incredible difference. The cool downdraught has completely gone, no more feeling of cold feet. All for the cost of two rolls of 200mm rockwool....
  4. This is a problem I've never heard of, just wondering if anybody else has come across it? Newly installed MVHR is a NUAIR XBOX 95, distribution is by 75mm semi rigid ducting. All ducting and manifolds are mounted in the loft, beneath about 300mm of rockwool insulation. Whilst adding additional lagging to the MVHR external air intake and exhaust ducts, I've noticed a lot of condensate inside the extract manifold. Perhaps sufficient to continue to accumulate and run along the 75mm ducts and potentially drip from the extract vents if left long enough. (The manifolds are home made, wooden, so will probably need to purchase a steel exhaust manifold) I think this is probably caused by hot, humid air from the family bathroom (following a shower being taken) meeting amd mixing with cooler air in the manifold being extracted from other (unused) bathrooms in the house. The manifold is below the loft insulation, so is adequately insulated but will clearly be below the temperature of air extracted during a shower, so I would think that condensation is inevitable? I'm proposing to add a condensate drain to the manifold, and link this to the existing MVHR drain, using an additional trap. Has anybody else experienced this?
  5. For some time, I've been considering the best way to integrate my cooker hood during MVHR installation. Having read the good words on here, it seems that direct integration from hood to MVHR is a BAD IDEA, so I've come up with this- Comments appreciated. My situation is this: 1) Large kitchen diner with induction hob plus 600mm externally vented extractor hood. There is no room to replace the extractor with a wider hood due to cabinets being in place. The hood does not cope with cooking smells/steam particularly well. 2) Cooker hood is too noisy. It currently vents externally. MVHR install requires changing to internal vent, which is likely to further increase noise levels and cooking smells 3) I don't want to link the MVHR and cooker hood ducts. However, the family bathroom is behind the kitchen/diner cooker wall. (loft is above) The family bathroom will have a high level of MVHR extraction, (higher extraction than the MVHR extract vent adjacent to the kitchen area) as extract noise is not greatly important in the bathroom. As part of the MVHR install, I'm removing 4 fairly new ducted fans from existing bathrooms. If I remember correctly, each of these have a capacity of around 240m3/hr. And they can be re-used... I'm considering : A) removing existing ducting and fan from the extractor hood. b) Install a 150mm duct between the cooker hood and bathroom, exiting fairly close to the MVHR vent. This vent to be fitted with a filter c) Mount 2 of my 'redundant' ducted fans in parallel into this duct. Fans to be operated by the existing cooker hood switch assembly. (I need to check out current draw first) d) Renew charcoal filters on the cooker hood, possibly adding further filters within the unused hood motor space. e) Connect the cooker hood to the MVHR such that hood usage boosts the MVHR . Whilst not perfect, I think this 'indirect connection' will: 1) improve efficiency of extraction of cooking smells. Better extract capability resulting from significantly lower (shorter) duct losses. Possibility to add further filtering within the empty cooker hood to reduce odour transfer to bathroom. (There will also be an MVHR kitchen extractor vent in the area) 2) Significant reduction of fan motor noise in the kitchen/diner as the ducted fans will be in the loft, outputting to the bathroom which is less noise sensitive. 3) Prevent grease contamination of the MVHR system as grease will be trapped within the cooker hood/duct filter assembly. 4) I'm hoping that additional activated charcoal filters within the cooker hood will prevent cooking smells reaching the bathroom. I realise that the amount of air I'll be transferring from the kitchen to the bathroom will exceed the extraction capabilities of the bathroom MVHR, however gaps below the door should take care of this. Comments welcome!!
  6. Hmm, if parcelforce decide it's a £57 delivery cost after pickup, I guess it's then too late to back out of the shipping, as they would probably charge to return it to your address, which would not suit either of us. I'd really prefer to take your offer, but unless you can see a way around it, the risk seems to great compared to the Blauberg deal, so I' think I'll reluctantly have to decline. thanks for the time and effort you have put into this. Incidentally, a 50m roll has just been sold on ebay for £45, buyer to pick up. (I'm not the buyer!)
  7. Hi thanks for your reply, firstly I must say the turtle in the background brings back memories - my child had one exactly the same- but quite a few years ago! Yes.I'd be interested at £80 plus 12:99 delivery, if you can manage to get it shipped at that price. Blauberg are selling their equivalent antibacterial at £79.49 so it's worth a little extra (the shipping cost that is, not the 61p!) to get the increased flexibility of the red airflow. If the shipping cost turns out to be significantly greater, then it may be better, as you say, to put it on ebay, buyer collection. Is it possible to confirm the shipping costs, then assuming you are able to work your magic on ParcelForce, how would you prefer me to pay for it? cheers Bryan
  8. Hi MJ, did you have any success with the ducting over the weekend😊
  9. £12? That's good! I've just been googling about, I assumed a pallet 1000 X 1200 x about 45. Weight about 25Kg. £57 is the best I could find. Maybe I'm overestimating the size/weight I wouldn't worry about photos, as long as there is nothing nesting/living/decomposing in it, I'd be interested.
  10. Thanks MJ, good info. I would be interested in your 50m roll of Airflow, however Wiltshire is a fair way from North Yorkshire. If you can let me know what you want for it, I'll investigate courier costs.
  11. Hey thanks for your kind offer-I may take you up on it, I'm just considering a few other items first. A further question- as part of the picking and choosing activity, I will probably end up using manifolds, plenums and ducting from different manufacturers. I'm assuming I use sealing rings from the manufacturer of the duct, irrespective of the source of the end fitting I'm using?
  12. Hi, yes I'm cherry picking from different suppliers, I've been checking out minimum bend radii for various semi rigids, it seems the blaufast and the quiet vent red versions both specify a min rad of 150mm, the quietvent blue is 250. the re is no spec shown on the BPC site for the green basic duct. Restrictors- thanks for the info, I'd assumed incorrectly that the restrictors would not fit the quietvent manifold. I will comission the system then see if significant throttling is required at specific vents where I require low noise, and use restrictors if necessary. If anybody is currently purchasing items, I've found that external bull nose vents are available at better prices on ebay, as is flexible insulated ducting, also on ebay.
  13. That's interesting. I've just looked on the website, there are various option for business type. Did you set up a business account such as 'plumber', 'MVHR installer', or a 'DIYer' account. I have a (now defunct) business name I could use if necesssary
  14. Hi and thanks for the good info. What a great resource this site is. I've spent many educational hours reading through the posts. I've now reconfigured my vents, and have 7 intake, 5 extract. However, in doing this, I have realised that the only way I can get a supply vent into bed 3 is to use a radial system- which raises more questions if I may: 1) I'm looking at BCP (quietvent) semi rigid 75mm. . The basic (green) seems to be significantly cheaper than the std (blue) at £95 vs £144. Both appear to have the same CSA, I don't need the smaller radius capability of the blue, so that leaves the only difference as I see it, as the blue having an antibacterial coating whereas the green does not. Is bacterial growth an issue? If so, does it make sense to use green on the extract side only? 2) System noise is an important item for us, esp in bedrooms. I have read somewhere here that system balancing by flow adjustment at the ceiling valve is more likely to create noise vs adjustment at the manifold. It appears that the quiet vent manifold does not have the option to use restrictors, leaving ceiling vent adjustment as the only option. However, what is the opinion on using a clamp on the semi- rigid pipe just downstream of the manifold to balance the system? I'm thinking of something like a woodworkers clamp during balancing adjustments, replacing these with a slotted piece of wood for a permanent fix. They could be removed for cleaning, A permanent set may result, but I guess this can be corrected for cleaning by lightly clamping at 90degs to the original clamp. 2) Silencers. Looks like a potential minefield, as I cannot see any specs for attenuation performance. Recommendations welcomed. However, as I see The Ventilation Hub on ebay , who I think are actually Blauberg, (not sure if I'm allowed links on here) are selling a 150mm x 600mm silencer at a good price. As my Nuaire XBOX 095 WH1 manual recommends having a min straight 300mm between the unit and any bends, I'm planning to mount the silencers vertically on the unit, then use flexi to connect to the duct work. Does anybody know of any downside to this? I was wondering if vibrations may be transmitted to the silencer from the unit. 3) Using radial ducting, is it usual to put a silencer on the extract duct? All my extract ducts are in rooms where some extract noise may be acceptable. 4) Woodburner- thanks for the guidance- my 5kW woodburner is not room sealed, however my logic is this: The wood burner air vents can be closed 100%, so when not in use, there should be virtually zero leakage through the stove.The woodburner is likely to be in use for maybe 6 hours/evening, for 50 days/year. That's 300/8760 hours/year when the MVRH won't work, which is acceptable for me. At these times, the MVRH can however supply combustion air to the woodburner, an additional benefit. Can anybody see any other downside? Thanks again for all the support this forum provides
  15. Hi, thanks for this info. I'll be getting some of this- perhaps also good in the external intake to prevent flies etc also? I'm just a little concerned about the cost- 1m2 used in two all my intakes would last only approx 300 years!! 😉