pulhamdown Posted February 25, 2018 Share Posted February 25, 2018 54 minutes ago, JSHarris said: 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. Our inlet filter is only a piece of slatted plastic with a plastic mesh insert. Definitely not very effective. I'll need to have a look and see if I can find something which screens more effectively without restricting the air supply. Perhaps Vent Axia sell one? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 25, 2018 Share Posted February 25, 2018 5 minutes ago, pulhamdown said: Our inlet filter is only a piece of slatted plastic with a plastic mesh insert. Definitely not very effective. I'll need to have a look and see if I can find something which screens more effectively without restricting the air supply. Perhaps Vent Axia sell one? 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. Link to comment Share on other sites More sharing options...
Stones Posted February 25, 2018 Author Share Posted February 25, 2018 @JSHarris and @pulhamdown, attached picture of the original filters I replaced last year. I would describe the fit as having a bit of wiggle, and as you can see no neoprene seal. The replacement filters I used were actually meant for a bigger unit but do have a snugger fit. Same filter material on metal frame. The darker of the two filters you see was on the air intake so caught all the insects. I'm not convinced many got round the filter, but suspect in removing the filter to clean some will have got shaken off or into the core while the filter was out. Link to comment Share on other sites More sharing options...
Declan52 Posted February 25, 2018 Share Posted February 25, 2018 I never had any bugs in mine which was surprising as we get a lot of midges where I am. Maybe the mesh cover on my vent tile is fine enough to stop any getting in. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 25, 2018 Share Posted February 25, 2018 This is what the filters look like in ours: They are a tight fit into a pair of channels top and bottom, with a neoprene seal at either end to make sure nothing gets past the filter. 2 Link to comment Share on other sites More sharing options...
pulhamdown Posted February 25, 2018 Share Posted February 25, 2018 I think we may be talking at cross purposes. The filter I referred to is the filter on the outside wall of the house, where the fresh air enters the system. My internal filters are as in the picture @stones posted. I would prefer to be able to stop the insects before they even enter the system Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 25, 2018 Share Posted February 25, 2018 19 minutes ago, pulhamdown said: I think we may be talking at cross purposes. The filter I referred to is the filter on the outside wall of the house, where the fresh air enters the system. My internal filters are as in the picture @stones posted. I would prefer to be able to stop the insects before they even enter the system All we have behind the wall terminal grills is a fairly coarse plastic mesh. Because the area is pretty small, compared to the area of the main filters, I think anything finer would clog with insects and cobwebs pretty quickly. As it is I find that I have to get a stiff brush up to the intake terminal a couple of times a year to remove stuff, often the fluff from some sorts of floating seeds. I have thought about relocating our fresh air intake a bit lower down, by adding an external duct and bend. Luckily it's completely hidden from view, in the narrow back alley between the house and the retaining wall, so wouldn't look obtrusive. One thing I'd like to do is add a large filter box on this lowered intake, so that I can try and stop insects getting inside the MVHR chamber before the main filter. Cleaning that out with a vacuum cleaner every 6 months is a pain, plus I think that the main pollen filter would last a lot longer with some form of pre-filter. If I get around to it then I wanted to make a vertical filter, with a gap at the base on the intake side to allow dead insects to drop out. Not sure how to do it yet, but I think a filter made from some smooth stainless steel gauze might work, and still be relatively easy to clean. Link to comment Share on other sites More sharing options...
PeterW Posted February 25, 2018 Share Posted February 25, 2018 I’m adding a 300mm square filter unit to the side of the MVHR that is 100mm thick. It will contain a 45mm G7 filter and a 25mm carbon filter so that leaves 15mm either side to allow for better air flow. Filters are cheap - I plan to swap every 6 months which I don’t think is an unreasonable cost for filtered fresh air.... Link to comment Share on other sites More sharing options...
Stones Posted February 25, 2018 Author Share Posted February 25, 2018 10 minutes ago, PeterW said: I’m adding a 300mm square filter unit to the side of the MVHR that is 100mm thick. It will contain a 45mm G7 filter and a 25mm carbon filter so that leaves 15mm either side to allow for better air flow. Filters are cheap - I plan to swap every 6 months which I don’t think is an unreasonable cost for filtered fresh air.... Do you have a link to what you are planning to install or are you making it yourself? Link to comment Share on other sites More sharing options...
PeterW Posted February 25, 2018 Share Posted February 25, 2018 10 minutes ago, Stones said: Do you have a link to what you are planning to install or are you making it yourself? Errr ... it’s a mix of both ..!! This is the filter box This is the G4 This is the carbon filter I will use some 10mm angle to create the slot for the filter pair which will be hopefully an airtight fit and ensure that both the dust and smaller stuff is kept out. Link to comment Share on other sites More sharing options...
Stones Posted February 25, 2018 Author Share Posted February 25, 2018 Have you calculated how much you will have to increase the flow rates by to compensate for the additional filter? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 25, 2018 Share Posted February 25, 2018 4 minutes ago, Stones said: Have you calculated how much you will have to increase the flow rates by to compensate for the additional filter? That's a good point, as that 292 x 292 x 45 filter has roughly about 60% to 65% of the effective area of the 415 x 220 x 50 pleated filter in our unit. I've found that the F7 filter has significantly more flow resistance than the G4 filter, though. Our unit was originally supplied with a G4 filter, and I later swapped it for an F7 filter and had to turn up the inlet side fan speed by a few percent to compensate. Link to comment Share on other sites More sharing options...
PeterW Posted February 25, 2018 Share Posted February 25, 2018 Given the fact the Mitsubishi units are vastly over powered for a house, I’m hoping (!!) it will give some welcome resistance to the inlet ..! The downside is that there is no ability to tune the inlet and outlet fans independently so I will probably end up with an adjustable iris on the extract to throttle the flow. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 25, 2018 Share Posted February 25, 2018 1 minute ago, PeterW said: Given the fact the Mitsubishi units are vastly over powered for a house, I’m hoping (!!) it will give some welcome resistance to the inlet ..! The downside is that there is no ability to tune the inlet and outlet fans independently so I will probably end up with an adjustable iris on the extract to throttle the flow. Or just add a filter in the main duct from the extract ducts to the MVHR? That would both help the balance and also keep house dust out of the unit. I found that the latter can be a problem, as I left our MVHR on by accident when we were doing the joinery, and ended up with loads of fine dust clogging the relatively low capacity filter on the extract side of the MVHR. Link to comment Share on other sites More sharing options...
PeterW Posted February 25, 2018 Share Posted February 25, 2018 8 minutes ago, JSHarris said: Or just add a filter in the main duct from the extract ducts to the MVHR? That would both help the balance and also keep house dust out of the unit. I found that the latter can be a problem, as I left our MVHR on by accident when we were doing the joinery, and ended up with loads of fine dust clogging the relatively low capacity filter on the extract side of the MVHR. That was my other plan - just concerns that the filter will absorb the moisture in the air from the extract side. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 25, 2018 Share Posted February 25, 2018 (edited) 3 minutes ago, PeterW said: That was my other plan - just concerns that the filter will absorb the moisture in the air from the extract side. Doesn't seem to on ours. IIRC there is something in the blurb about the pleated filters that says they are made from a hydrophobic material, so the thing tends to repel moisture. Edited to add: I've just checked and this is the case, plus the filter on that side is a G4, presumably because all it needs to trap is house dust Edited February 25, 2018 by JSHarris Added info 1 Link to comment Share on other sites More sharing options...
Stones Posted February 25, 2018 Author Share Posted February 25, 2018 I've never seen any sign of moisture on the extract filter, or in the extract distribution box. It genuinely appears that moisture only condenses in the core (hence the mould growth at the discharge point) @PeterW do you only have fixed speed settings on your unit? Do you know what volume of air those speeds are set at? Link to comment Share on other sites More sharing options...
PeterW Posted February 25, 2018 Share Posted February 25, 2018 2 minutes ago, Stones said: I've never seen any sign of moisture on the extract filter, or in the extract distribution box. It genuinely appears that moisture only condenses in the core (hence the mould growth at the discharge point) @PeterW do you only have fixed speed settings on your unit? Do you know what volume of air those speeds are set at? It is fixed speed - need to dig the volumes out. I may put a pleated filter into the front of the extract box just to balance the flows. Link to comment Share on other sites More sharing options...
JOE187 Posted February 25, 2018 Share Posted February 25, 2018 https://uk.rs-online.com/web/p/filter-media/1221772/ I use this filter material on my outside inlet in front of the mesh screening catches all insects and grime, makes the internal filters last twice as long before cleaning or replacing! Both my MHVR units have this on the external inlets and need changing every 3 to 4 months 1 Link to comment Share on other sites More sharing options...
readiescards Posted December 6, 2018 Share Posted December 6, 2018 What is the best way to clean the dust of the fans (of a Vent Axia Sentinel Kinetic Plus B in my case) - it is tedious and not very effective with a tooth brush Link to comment Share on other sites More sharing options...
Dreadnaught Posted December 6, 2018 Share Posted December 6, 2018 19 minutes ago, readiescards said: What is the best way to clean the dust of the fans (of a Vent Axia Sentinel Kinetic Plus B in my case) - it is tedious and not very effective with a tooth brush Can of compressed air? Forgive my ignorance, but wouldn't the dust usually be caught by the filters (which it clearly isn't otherwise you wouldn't have posted)? Or is it fine dust that passes through the filter? Link to comment Share on other sites More sharing options...
Declan52 Posted December 6, 2018 Share Posted December 6, 2018 I just let Henry at it and give it a quick hoover out. Never really that much though. Link to comment Share on other sites More sharing options...
Stones Posted February 9, 2020 Author Share Posted February 9, 2020 Bit of an update, 3 years in. I've been changing filters every 6 months and servicing the unit (core, fan blades, drain) every 12 months. Last night, some odd noises coming form the exhaust vents, which made me think a bearing had gone. So today's job was checking. And this is what I found... Thankfully all on the exhaust side after post the heat exchange core. The cause of all this was the condensate drain being blocked with mould and 'biojelly' (see last pic, the large black area). It would seem that in not draining away, water has overflowed or been pulled into the exhaust fan chamber where it has obviously coated the fan blades and walls of the chamber. No warning indicators or lights to suggest a problem of course. So, having found the problem, I had to take the whole unit apart, remove the top and sides (which slide and interlock with each other)to get to the back of the fan. Unbolt and remove fan to get into the chamber. Interestingly, this seems to be the only way you can properly clean the fan blades as you certainly can't do it from inside the main body of the unit. A lot of wipes used to remove the mould, then a generous application of bleach to kill the nasties and clean it up. Fan blades cleaned and all reassembled. Should be easy but took best part of the day, in large part due to the poor design of the unit. Screws and fixings (referenced earlier) used to secure body panels were a real pain, and I think I'm going to ditch them in favour of cam lock belts. Condensate drain not easy to clean through (must get a bottle brush). Best part of £1250 for one of these units and this is what happens. Never had this problem before, having had MVHR (different makes) in 5 previous houses. I am not a happy bunny right now. Link to comment Share on other sites More sharing options...
Declan52 Posted February 9, 2020 Share Posted February 9, 2020 They have to have updated the panel fixings by now for their latest versions. It's like they spent thousands and thousands of £££ to design the inner workings of the unit and then 2p on how you attach it all together. I have never went as far as checking the fan in mind but maybe for a bit of peace of mind I might do it when it's next due the filter change in April. Link to comment Share on other sites More sharing options...
Stones Posted February 9, 2020 Author Share Posted February 9, 2020 @Declan52 just shine a torch into the fan when you have the heat exchanger removed. You WILL know if you have a problem. 1 Link to comment Share on other sites More sharing options...
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