Steve W Posted February 14 Share Posted February 14 I have a Domus HRX2 MVHR that I installed in 2018. It would appear that one of the fans has started to fail and although it is not noticeable during the day, during the night it is audible and makes getting back to sleep difficult. I have been in touch with Domus and they have told me that the fans for this unit are no longer available however the fans from the HXR2D are mechanically the same - different connector (I'm a retired electrician so this isn't a problem). The parts are SPR425 and SPR426with a price of £409.75 each + VAT and £10.00 delivery. The original unit only cost j£1073.00 inc VAT and delivery so nearly a £1000 pounds for fans seems exorbitant. Has anybody had any dealings with these fans? Is it possible to replace the bearings as I've seen another post where standard bearings from Amazon have been used to remediate a problem? Are there any firms that specialize in reconditioning these units? How long should a fan last that runs continuously? Would a Nuaire MRXBOXAB-ECO2 be a suitable replacement albeit I would need to rework the pipework slightly. Given the cost of two fans I am seriously considering replacing the unit with one from another manufacturer that has more cost effective spares. Any advice would be greatly appreciated. Steve W I have access to bearings pullers and a vast array of tools as well as a mate who has machining facilities if needed Link to comment Share on other sites More sharing options...
Iceverge Posted February 14 Share Posted February 14 Have a look at the bearings. £5 could gona long way. Our extractor fan will need them replaced at some stage. Maybe another year. Link to comment Share on other sites More sharing options...
Steve W Posted February 14 Author Share Posted February 14 Domus supplied with a document on how to change the motor which is reasonably straight forward. I have extracted a photo of the fan unit just in case anybody can identify it. Link to comment Share on other sites More sharing options...
Iceverge Posted February 15 Share Posted February 15 I'd you can get to the bearing then have a look at the number stamped on it. It's normally an off the shelf item. Most motor factors would have one in stock. Link to comment Share on other sites More sharing options...
Steve W Posted February 15 Author Share Posted February 15 I've just had another price for the two fan units, £1300.00 inc VAT plus delivery. Hopefully they should be standard bearings which are freely available. I use simply bearings that offer a next day service and have top notch makes. It will be mid to end March before I can strip the unit too many other jobs now im retired. Will document the process to help others. 2 Link to comment Share on other sites More sharing options...
iainf Posted March 5 Share Posted March 5 Hi, I find myself in same position, 2017 diy install, balance flow and return per room so can run minimal speed and not defeat acoustic and smoke seals on doors. Surprisingly had a sensor fail - will be conformal coating the replacement so it lasts longer, went to put new sensor up near unit (will run with faulty temp sensor with bypass disconnected) and heard bearing on it's way out. Huge price for replacement fan. I believe likely to be papst fan. Previous house I had an airminder and replaced the bearings in the papst fans in that - brushless motor so no armature / brushes to wear, just the bearings. hopefully Papst motors are still possible to replace bearings. There will be more of these needing done and huge waste to replace a perfectly good motor just for the sake of some bearings. I can't find record of what I bought the last time, but I do remember I went for the uber version as cost was nothing compared to new fan. I'm planning on replacing the bearings in this unit now, however getting the time is another thing. Can you get the model number of the fan in the photograph and verify it is a papst? Link to comment Share on other sites More sharing options...
Steve W Posted March 7 Author Share Posted March 7 Hi Iain, It may be some time before I will be stripping down the MVHR unit - bogged down in flooring at the moment. The picture is from the instructions I got from Domus on how to the replace the fans. I have attached the guide as it may make it slightly easier. Steve W Domus Ventilation - Changing HRX2D Replacement Motors - SPR425-SPR426 (1).pdf Link to comment Share on other sites More sharing options...
JohnMo Posted March 7 Share Posted March 7 On 14/02/2024 at 18:24, Steve W said: price of £409.75 each + VAT Sounds rip off, my Triton fan/motor was £276, incl vat and delivery. I thought that was expensive. Link to comment Share on other sites More sharing options...
Steve W Posted March 7 Author Share Posted March 7 Not as bad as £1300.00 (2x£650) that I was quoted elsewhere! (plus postage). I will not be buying a Domus replacement should the need arise. Link to comment Share on other sites More sharing options...
iainf Posted March 7 Share Posted March 7 I'm very hopeful that it will be a bearing swap. No way should we be scrapping whole units just for the sake of some fans that should be serviceable. Does anyone know the markup on them? RS prices are in that region for similar fans, here's hoping they haven't deliberately made them unserviceable or really awkward to keep alive. The hex will be due a clean anyways as have never done it since installed, just the filters at season change, I take air from the loft in winter rather than from outside. Sounds like I may be having to prioritise this as bearings much louder so have had to turn off. I'll update with what I find. Link to comment Share on other sites More sharing options...
iainf Posted March 9 Share Posted March 9 I'm very hopeful that it will be a bearing swap. No way should we be scrapping whole units just for the sake of some fans that should be serviceable. Does anyone know the markup on them? RS prices are in that region for similar fans, here's hoping they haven't deliberately made them unserviceable or really awkward to keep alive. The hex will be due a clean anyways as have never done it since installed, just the filters at season change, I take air from the loft in winter rather than from outside. Sounds like I may be having to prioritise this as bearings much louder so have had to turn off. I'll update with what I find. Link to comment Share on other sites More sharing options...
iainf Posted March 9 Share Posted March 9 I have extracted failing fan, very very dirty rotor covered in dust n fungus so that will need a good clean, hopefully not disturbing any balance weights. Wonder if growth built up in balance? Fan motor number there, I'm timed out for tonight so will have to pick up next opportunity. There are YouTube vids for similar fans if you use search on bearing replace ebm papst fans, not sure which one will be closest to the hrx2 one yet. No connectors, wire ends straight to screw terminals in control panel. Motor I have to replace bearings in was already a replacement as I had a dud fan bearing in new unit, pretty annoyed as had to strip unit down to get into loft, rebuild and then find duff bearing, refused to send whole unit back as they wanted, so got away with getting just the replacement fan. 1 Link to comment Share on other sites More sharing options...
Steve W Posted March 10 Author Share Posted March 10 Thanks for the update - that fan looks totally disgusting! I have had a look at the YouTube video (https://youtu.be/QmdSoj7Gr90) and its looks to be a straight forward job using 8 x 22 x 7 bearings (608 series). I have had a look through the various bearing suppliers and I will be buying 4 x SKF E2.608-2Z/C3 given that they have an excellent specification. SKF Energy Efficient Bearings - Optimized to increase service life SKF Energy Efficient (E2) deep groove ball bearings can provide more than twice the service life while reducing energy use and total cost of ownership. Design improvements reduce frictional losses in the bearing by at least 30% when compared to the same size SKF Explorer bearing. This results in energy savings over the life of the application. Benefits Longer Bearing Service Life Longer Grease Life Reduced Operating Temperature Higher Speed Capability Sustained Performance Reduced Energy Use Lower Cost of Ownership Boundary dimensions in accordance with ISO15 - which makes them dimensionally interchangeable with standard deep groove ball bearings Reduce Friction Means Increased grease life and service life Optimized to reduce frictional losses and operating temperature in the bearing, capped SKF Energy Efficient deep groove ball bearings can last at least twice as long as comparable SKF Explorer bearings in many applications. This means that in applications where conventional bearings fail and are replaced, the longer service life of SKF E2 bearings could potentially halve the number of bearings consumed over the machine lifetime or even eliminate the need for replacement altogether. In instances where an application is run-to-failure, SKF E2 bearings could conceivably double the life of the application, consequently reducing the total cost of ownership. It would appear from the YouTube comments that life expectancy of bearings is of the order of 4.5 years. Link to comment Share on other sites More sharing options...
Steve W Posted March 10 Author Share Posted March 10 Not Cheap but it is in stock and a lot less than buying one from Domus. Link to comment Share on other sites More sharing options...
iainf Posted March 11 Share Posted March 11 The C3 spec has extra clearance for high temp running so may not be the best if it rattles around as not running hot in this application. I've gone for the low friction rubber seal ones as the bearing that's gone is the more exposed one. I've bought a removal tool, same size bearing on skateboards so tool sensible price, don't think in tight anyway so probably ok to get out carefully without special tool. I'll post more once got the tool and bearings. Link to comment Share on other sites More sharing options...
iainf Posted March 11 Share Posted March 11 SKF 6082RSL Deep Groove Ball Bearing with Two Low Friction Rubber Seals 8x22x7mm, £26.22 inc VAT and 1st class postage (paid for quicker delivery than free option £2.25) simplybearings. Skateboard Accessories Bones Bearings Bearing-Tool £12.25 from Amazon Link to comment Share on other sites More sharing options...
iainf Posted March 11 Share Posted March 11 that's for 4 bearings, may as well do both fans even though outside air induction one seems fine at the moment, pain to strip it all down. Heat exchanger amazingly clean - guess all that filter didn't catch was on the rotor so not complaining 🙂 1 Link to comment Share on other sites More sharing options...
Steve W Posted March 11 Author Share Posted March 11 Matters have taken a turn for the worse! Previously the noise from the MVHR was merely annoying - yesterday it became louder and I have to switch it off at night. I ordered the bearings from Bolton Bearings so should be here in the next couple of days. I had noticed that the bearing has extra clearance and will report back if the clearance is an issue. It's a surprisingly common bearing and used in lots of application which presumably is why it is so plentiful and cheap. The next generation of fans will probably have bearings that are not removable and are a custom size - after all you want people to buy the expensive fans. 1 Link to comment Share on other sites More sharing options...
iainf Posted March 18 Share Posted March 18 all done and dusted as far as the bearings are concerned - I did leave the original intake bearings in out of interest to see how long they last as they are still sweet. Have made it a bit easier to service the next time - keyholed the wall hanging brackets so can hook it on then tighten - originally designed by someone who has never actually had to install one (or anything much at all tbh). I used the better sealed version, not the original metal shield as the failed bearing was the one most exposed to the humid extract air, hopefully a very long time until that one needs doing again. Videos on you tube we linked above helpful, care points are to make sure you lift off and place the fan driver PCB vertically on and off in the correct orientation - there's a sensor has to fit into it's slot and 3 power pins to get into their connectors on the PCB, mash those and big bills. When cleaning the fan be careful not to disturb any of the metal balance weights - they are really good quality fans and one thing that is being paid for is each one individually balanced - they are in the slots front and back so easy to clean dirty bits of fan without disturbing - nice design. issue I have now is loss of temperature and now humidity readings not fixed by new sensor - have asked how much a new controller is. Calling for bypass all the time so disconnected that which is ok for now. Anyone else had any issues with the bluebrain controller - mine is early one I think so maybe teething troubled version of pcb that doesn't like getting turned off and on. Link to comment Share on other sites More sharing options...
Steve W Posted March 18 Author Share Posted March 18 Bearing swap complete. No problems changing the bearings, getting the case square again was tedious. I have outlined the steps in the attached document. DOMUS HRX2 Bearing Change.docx Link to comment Share on other sites More sharing options...
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