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Sunday 31 May 2020

Ideal Mini C24 - fan replacement

So, we're in the Chinese Virus lock-down and I was thinking that it was about time I replaced the fan in my boiler. The current fan is on its last legs - the bearings are shot and the fan is noisy and keeps seizing. When this happens the boiler won't fire at all (so no heating or hot water). I've been able to effect a temporary repair each time by opening up the boiler and squirting some WD40 on the bearings. The repair lasts a few weeks or a month or so, and then the fan seizes again. Last week I found a "nearly new" fan for sale on Ebay so I bought it - £40 delivered. Today I fitted the new fan and this is how.



This is the boiler. I sprayed the panels black a couple of years ago. Note the wooden panel underneath. I made this to cover up the abominable pipework underneath...



What on earth were they thinking?




Anyway, here are the required tools. The thing at the top is the longest cross-head screwdriver I could find. I also used a flat-head screwdriver, as will become apparent in a moment.



Right, the outer panels are now off. The power supply to the boiler is also off! Next step is to open - slightly - the tabs holding the inner panel in place. There are three tabs on each side.




Next, undo the four screws on the front of the inner panel...



... and the screw on each side of the inner panel. The inner panel should pull forward and away.




This is what's behind the inner panel. The five screws in this picture will need removing in a moment. Before that, some fettling in the fan area is required. The fan is in the top right-hand corner of the picture.



First, undo the two screws holding the fan/flue together. With the screws removed, completely remove the front bracket. Note that the screws go into captive nuts on the back of the bracket. Still, it is worth putting a bit of tape over the nuts just in case they are no longer captive...



Thus...




Disconnect the electrical connections to the fan (including the earth wire on the side.



Pull the wire and grommet away from the fan shroud. Also, there are also two soft hoses attached to the fan body which should be disconnected. Make a note of which hose goes where.



Now undo the five screws on the front of the inner panel and remove the panel. Be very careful with the panel - it is lined with fireproof material which I imagine would shatter if the panel was dropped or flexed.



This is what the boiler looks like with the front inner panel removed. It might be possible to remove the fan from its shroud at this point. It is held in place by three small screws accessed from underneath. To be honest, I couldn't be bothered even trying and instead removed the fan and its shroud in one go.





The three pictures above show the location of the fan shroud screws. The screw in the picture immediately above requires use of the long screwdriver. Once removed, very carefully slide the fan and shroud forward, checking that no pipes or cables are tangled up in it. Expect the plastic join between the fan and the flue to come away at this point.



Fan and shroud removed.



This is underneath the shroud. The three screws holding the fan in place can be seen. Remove the screws and the fan comes away.










The pictures above compare the old and new fans. Note the date code on the old fan. And the new fan was made a couple of years ago, it seems. The part number says it is for the C28 or S28. However, it is identical to my old fan and is minty mint. I believe the ebay seller who advertised the fan as having only three-day's use. It also came with a new seal for the flue bracket so I used that rather than buying a new one.



New fan attached to the shroud.


Re-assembly is reverse of removable but with the following notes:



When sliding the fan shroud back into place, take care not to pinch any hoses or electrical cables. Also, it is unlikely that the fan will properly line up with the flue bracket at this stage. This is because the fan shroud is propped up by the front inner panel which isn't fitted yet. So, once the shroud is in roughly place, refit the front inner panel and only then final-fit the fan. 




This is the flue bracket back in place. 



Power and pipes reconnected. But also note the close-up of the spongy seal that goes between the inner panel and the rest of the case. "Ideal" recommend replacing the seal when the front panel has been removed. However, I replaced this seal recently so it is still nice and spongy. The original seal was hard and crispy and I had no confidence in it (not that I think a problem with this seal will cause any issues other than the boiler not igniting due to lack of vacuum in the combustion area).



Once the inner panel is reattached and screwed on, gently tap the side tabs back into place to ensure a snug fit (three tabs on each side). Then, with power back on, I tried the hot tap. Boiler fired up first time and is so quiet - no rumble from dodgy fan bearings!



I then conducted some safety tests with my carbon monoxide detector. With the doors and windows closed, no detectable CO after 30 minutes of running. This can be compared with when I'm using the wok burner on my gas hob - with doors and windows closed and the hob extractor off, the detector reports trace amounts of CO in minutes (but never high enough to set the alarm off).  I will conduct further tests just to be sure but I am happy that the boiler is safely operational. Incidentally, my CO detector lives on the wall next to the boiler.


More soon, no doubt...


D
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11 comments:

  1. Alan24 August 2020 at 18:05

    Best. Blog name. Ever. I reference that quote at least once a year, and have been since 1993. :)

    ReplyDelete
  2. Dave24 August 2020 at 18:29

    If you know, you know :)

    ReplyDelete
  3. Charlie20 December 2022 at 20:34

    Hi there, I have the same boiler and recently decided to replace some worn out parts after reading your blog. Was wondering if you have a manual or tips for working the timer? Also do you have the boiler rigged up to a room thermostat or does it just work off the internal boiler thermostat and radiator trvs? Cheers

    ReplyDelete
  4. Dave20 December 2022 at 20:48

    Hey Charlie - thanks for the comment. To be honest, I couldn't understand the timer at all. Instead I use a Honeywell wireless digital thermostat which lives in my front room. I've programmed that with times and temperatures (with a different routine at weekend as we're all at home at weekend). This controls a unit which sits on the wall next to the boiler and is wired in in place of the Ideal timer. Very easy to fit and much more straightforward and flexible to use. But if you must use the Ideal Timer, this might help: https://www.freeboilermanuals.com/assets/User_Manuals/Ideal/ideal-minic24-7-timer.pdf

    ReplyDelete
  5. Charlie21 December 2022 at 15:42

    Hi Dave thanks for getting back to me and for sharing the link. I'd much prefer a wireless option, I didn't appreciate that would be an option on an older boiler such as ours. Could you let me know the model numbers for the wireless thermostat and unit next to the boiler that you use please? Thanks again

    ReplyDelete
  6. Dave21 December 2022 at 16:28

    Hello again. My stat is a Honeywell CM67NG which is quite old now and discontinued a few years ago. Really, all these things work on the same sort of principle - the wireless unit checks the temperature wherever you site it, and the other end basically switches the boiler on or off as required. The wiring into the boiler is straightforward. If I was replacing my stat today, I'd go for the Honeywell T3 from Screwfix for £87.

    ReplyDelete
  7. Charlie21 December 2022 at 19:44

    Thank you Dave, I appreciate your input, and thanks for the tip about the T3 too, will look into that. Hope you manage to keep your boiler going, they seem reasonably well put together and as you say fairly easy to work on. All the best, Charlie

    ReplyDelete
  8. Charlie4 January 2023 at 17:02

    Hello again Dave, I recently picked up the T3R as you suggested. But I'm having a struggle finding the T1 and T2 terminals on the boiler? Do you recall where they are located. was wondering if they are part of the 4-pin cable that joins the original programmer to the main board? If so did you leave the original programmer wired up and bridge into that wiring? The original instruction manual re. installing the original programmer only describes the wire colouring and not the terminals. Any advice greatly appreciated!

    ReplyDelete
  9. Dave4 January 2023 at 17:40

    Hi Charlie. It was a long time ago and I cannot remember what I did except that it was very straightforward. Probably easiest if I just open my boiler up and take a look and maybe some photos for you. I'll get on that later this evening and then add the pictures somewhere on this blog.

    ReplyDelete
  10. Dave4 January 2023 at 18:51

    Might not be able to do pics tonight but have a look at the boiler installation manual, details at sections 21, 22 and 26. That is what I worked to. There's a choc block under the plastic lid of the control panel, left hand-side, that has a loop of wire across two of the three terminals. You remove the loop and connect T1/T2 of your stat switch in its place. If you need mains power to your stat, you can take that from the other choc block in there. Section 22 has a schematic with the wire colours. And whilst I know you will, I feel like I have to say it anyway - make sure your boiler is switched off at the mains before starting work! https://www.freeboilermanuals.com/assets/pdf/ideal/mini_is32.pdf

    ReplyDelete
  11. Charlie5 January 2023 at 08:54

    Thanks for this, the manual you linked there is actually far clearer than the versions I have. And what you describes confirms what I was thinking. Will have a good go at wiring it up later today, with the electricity off! Thanks again

    ReplyDelete

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