DOIGAN Posted February 6, 2021 Share Posted February 6, 2021 (edited) Hi All, Hopefully this will help someone as I could not find anything online. I was about to pull the trigger on a new fan which is really limited as to where you can get them and expensive. A new fan from Vent Axia is £280 I sourced bearings from Amazon for £7. Below is a series of pictures showing the fan in various states of disassembly. To remove the fans from the unit requires a full strip down of the unit unfortunately, this is not difficult just a pain, especially if your unit is in the loft like mine. Picture 1 This shows the fan body from the top, first remove the 3 screws in red, gently pry off this black housing, this houses the contacts so go easy, it does lift off without any resistance. Now remove the other two screws in blue. Picture 2 The contacts mentioned above that you will not want to damage. Picture 3 This show the fan in two main parts, the upper with the circuit board and the body that houses the bearings. You can remove the circuit board but I would advise against it, no reason to unless you think it is faulty. Lift off the white rubber cap (red dot) to reveal the upper bearing. Picture 4 This shows the upper bearing already removed with the retaining clip (blue dot). The clip is really small and a bit fiddly, if you push down on the hub assembly if will give a little space between the clip and bearing, this will allow you to get a plain bladed screwdriver into the clip and spread it slightly to remove it. Once the clip is off just lift the whole hub assembly out, it is not stuck or tight but held in magnetically so just pull up. ;Picture 5 This shows the underside of the hub with the bearing already removed, the bearings are easily remove as they are not tight inside the hub, just gently tap them using a long screwdriver from inside the spindle shaft hole, you will see them move out. Picture 6 This just shows a spring with a flat washer on top of it, just in case it drops out when you are lifting the hub etc, just leave it in place. The blue dot shows the magnet Re-assembly is just the reverse when you put the new bearings in. The bearings are marked 626-2Z, these are the one I got from Amazon. https://www.amazon.co.uk/gp/product/B07FMV2ZHR/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 Hope this is useful to someone. Edited February 6, 2021 by DOIGAN more info 4 3 Link to comment Share on other sites More sharing options...
JamesP Posted February 6, 2021 Share Posted February 6, 2021 Have the same unit fitted so much appreciated. Have bookmarked. Link to comment Share on other sites More sharing options...
DOIGAN Posted February 6, 2021 Author Share Posted February 6, 2021 Just now, JamesP said: Have the same unit fitted so much appreciated. Have bookmarked. You are very welcome. Link to comment Share on other sites More sharing options...
ProDave Posted February 6, 2021 Share Posted February 6, 2021 Thank you a very good write up which I am sure will help many. Link to comment Share on other sites More sharing options...
PeterW Posted February 6, 2021 Share Posted February 6, 2021 Have pinned this as a really useful reference. Link to comment Share on other sites More sharing options...
DOIGAN Posted February 6, 2021 Author Share Posted February 6, 2021 16 minutes ago, ProDave said: Thank you a very good write up which I am sure will help many. Thanks, it's nice to give something back. People on here are extremely helpful when asked, which I have done a few times already. Link to comment Share on other sites More sharing options...
MJNewton Posted February 6, 2021 Share Posted February 6, 2021 Yes, thanks for this. We've got a Titon MVHR which uses ebm-papst fans and so chances are there are a number of other units that also do. Link to comment Share on other sites More sharing options...
Savage87 Posted February 8, 2021 Share Posted February 8, 2021 On my unit, a Nuaire MRXBOX-ECO2, one of the fans vibrates consideraly more at about 25%, If I set it to 10% or if the unit is on boost at about 50% there's no vibration. Could it be the bearing that's at fault? Link to comment Share on other sites More sharing options...
dpmiller Posted February 8, 2021 Share Posted February 8, 2021 possibly, but check for an imbalance issue- loose or missing balance weight, debris in the fan. Most rotating objects go through an imbalance period but smooth out past that speed, any looseness in the bearings may exacerbate it . Link to comment Share on other sites More sharing options...
Savage87 Posted February 8, 2021 Share Posted February 8, 2021 I opened up the box, took the heat exhanger out to get access to the fans and the fans seem solid and no sign on any debris. Link to comment Share on other sites More sharing options...
Bonner Posted February 8, 2021 Share Posted February 8, 2021 2 hours ago, Savage87 said: On my unit, a Nuaire MRXBOX-ECO2, one of the fans vibrates consideraly more at about 25%, If I set it to 10% or if the unit is on boost at about 50% there's no vibration. Could it be the bearing that's at fault? This is resonance where the amplitude of vibration increases at the natural frequency. Any part of the structure can resonate, the fan, bearing, housing, case or some other part which is in contact. To rule out resonance of any part of the structure you need to try to damp the vibration while it is running at 25%. You can do this by simply putting your hand on the part (if safe to do so), bracing it or adding mass. If you can’t damp out the vibration, either the fan is out of balance or the bearing worn. Link to comment Share on other sites More sharing options...
Savage87 Posted February 8, 2021 Share Posted February 8, 2021 The MVHR is wall mounted on a solid brick wall(party wall in the loft). When I'm in the ground floor hallway downstairs and I put my ear on the wall you can hear the resonance. i have put thick carpet underlay on the party wall and between the mvhr and the wall + at least 50mm of rockwool all around the unit and a a osb box all around. you can bearly hear the unit when next to it but it does resonate when the extract fan is at 25% (where it should be balanced). Link to comment Share on other sites More sharing options...
joe90 Posted February 8, 2021 Share Posted February 8, 2021 Is the unit on rubber mounts to stop noise/vibration going into the wall?. I hung mine from the roof trusses to stop noise into the house. Link to comment Share on other sites More sharing options...
Savage87 Posted February 9, 2021 Share Posted February 9, 2021 It has rubber mount on the lower back and 2 metal brackets on the upper back. I was expecting the carper underlay to dampen some of it but it didn't do much. Link to comment Share on other sites More sharing options...
dpmiller Posted February 9, 2021 Share Posted February 9, 2021 so the plastic case is directly on the wall then, the top hangers aren't isolated IIRC. Need to rubber-isolate the hanging points or maybe build a shelf and set it on it, over a rubber layer. Link to comment Share on other sites More sharing options...
Declan52 Posted February 9, 2021 Share Posted February 9, 2021 Mine is on a shelf sitting on rubber underlay. Had no issues with vibrations in 5 years. Link to comment Share on other sites More sharing options...
Savage87 Posted February 9, 2021 Share Posted February 9, 2021 I had no issue for the first couple of months, it's something that I had to deal with recently. Link to comment Share on other sites More sharing options...
Gone West Posted February 10, 2021 Share Posted February 10, 2021 14 hours ago, Savage87 said: I had no issue for the first couple of months, it's something that I had to deal with recently. Just a thought but have you checked that the outside inlet vent is clear. I have noticed that the fans have to work a lot harder when the vents become blocked. Link to comment Share on other sites More sharing options...
Savage87 Posted February 10, 2021 Share Posted February 10, 2021 a bi tricky to check it at the moment, it's on the roof.. near the ridge. I will check it soon just to rule it out. Link to comment Share on other sites More sharing options...
Cooeyswell Posted February 19, 2023 Share Posted February 19, 2023 Many thanks for this post. A fan in my unit is getting noisy after 7+ years, this looks like the solution Link to comment Share on other sites More sharing options...
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