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

Ideal Mini C24: Fix or replace?

It had to be a fix, really. Even if I had the money, I'm not paying a guy a grand for one day's work swapping a boiler over. Unfortunately I don't have the money so this was only ever going to be a fix.

Righty, my boiler is an Ideal Mini C24. It's a gas "combi" so delivers hot water on demand. There is no hot water tank. From various labels stuck on it, it seems to have been built in 2004 which means that it is getting on a bit. I don't know who fitted it but they could do with some lessons in pipework. There is literally a nest of pipes weaving in and out of each other under the boiler. But that is mainly aesthetics. My boiler had several issues which required attention:

• The central heating circuit would lose about one bar of pressure during the course of a week (but no visible leaks on the circuit)
  
• Running a hot tap would cause all the radiators to get warm
  
• Whether it was central heating or hot water, the boiler was noisy (not unlike the sound of a boiling kettle but perhaps a bit more rattly)

So, I did a bit of research. The first thing I looked at was whether I was allowed to work on my boiler at all. The Gas Safe Cartel... sorry... Gas Safe Register would evidently prefer it if I was legally barred from even thinking about working on my boiler. Alas, that is not what the law says and the GSR appears to accept that (without enthusiasm, evidently), in one of its downloadable leaflets. The true position seems to be this: where the law applies, a person working on the boiler needs to be competent. Moreover, it seems doubtful that even that legal requirement applies where the job does not involve interfering with or touching the gas side of things (the gas pipes and valves, any module which controls gas, and within the combustion chamber and flue). Lucky for me, then, my research suggested that all my boiler's issues were on the "wet side" of things. This is where I ended up:

• the pressure drop in the central heating circuit was likely to be a faulty or dirty pressure-release valve
  
• the issue with the hot tap and radiators was due to a faulty or jammed diverter valve
  
• the noise was due to a partially blocked secondary heat exchanger (which is where the mains-fed cold water is heated for the purposes of the hot tap)

Since I was still reeling at the prospect of laying out for a new boiler, I didn't mind spending a bit on some new parts (Ideal part number in brackets):

(172494) Pressure release valve

(172507) Diverter valve repair kit

(075460) HW Heat exchanger

(172525) Auto air pressure release valve

(172504) By-pass pipe

(075412) By-pass pipe o-ring (x2)

The last two items on the list were necessary because the original by-pass pipe (being push-fit and held in place by spring clips) had had a liberal dosing of "plumber's mate" or some such white stuff, during original fitment. I ended up wrecking the pipe when trying to remove it because it was stuck fast. Total bill for parts  was £110. Apart from the by-pass pipe, everything else came from ebay. I also bought a second-hand replacement temperature/pressure gauge as the one on my boiler had stopped working in both respects...

As far as the job goes, all in all it took a couple of hours. I'd never drained-down a boiler before so had to read up on that, and make preparations in my new kitchen for potential water spillage. Luckily, there was not too much mess. It also only occurred to me after starting that I would need to replace the fibre washers in various bits that I was disconnecting, so I had to nip out for those. I'm not doing a step-by-step because removing and replacing the parts is actually quite straightforward. In terms of tools, I used a couple of different sized wrenches, an allen key and a screw driver. Nothing special was required. 

Everything I removed was caked-up internally with gunge. The PRV was obviously leaking (draining down a pipe which led through my kitchen wall and into a garden). The air pressure release valve had failed in the "open" position so was presumably letting air into the system whenever the central heating was cooling down. The internals of the diverter valve had seized rendering the valve un-operational (hence the warm radiators whenever the hot tap was run). As far as the noise was concerned, the HW heat exchanger was likely partially blocked - certainly, with the new part fitted I now have pretty much mains pressure hot water which is actually very hot indeed! And the boiler runs so quietly! I'll let everything settle in and confirm no leaks. I'll then look to doing some sort of system flush and add some rust inhibitor.

Here are some pics of the old parts:

More soon, no doubt....

D