I have an old warmair central heating system that I just love to bits but do have an issue with the Johnson and Starley fan unit. This is part number 1000-0500370. There is a really stupid design fault with this unit as the fan bearing is a sealed one with no way of lubricating it. The fact that the hot air blows over it has an obvious effect of the bearing drying up and causing a unit failure.
The cost of replacement is really quite steep at around £350 for a new fan unit. It isn't a DIY job to replace the bearing so you're pretty much stuck to replacing the whole unit. I have searched everywhere for someone who does a refurbishment of the unit but aren't any showing up. I guess if there were it would still be costly anyway.
TAKE NOTE: I have sorted this out and applied it over around 8 years or so. First of all, the reason that this has become a topic now is that the bearing started squealing again yesterday and shut the fan down.
So what's the fix? Easy. The bearing end cap is a dome shape on the outside of the unit. I drilled a very small hole in the cap to allow access. I then obtained a syringe with a very small diameter needle and filled it with a mix of ordinary 3 in 1 oil and ZX1 additive. Initially just a small squirt of the ZX1 before using the mix. The info on it is here: https://www.team-zx1.com
Place the needle into the hole in the end cap and tape the syringe to the unit's side wall or elsewhere so that it provides a slow drip feed into the bearing case.
Within 3 minutes of awful squealing and crackling, the bearings picked up the oil and now work perfectly well.
Of course the use of oil, even small amounts in a heating system might seem questionable but I think that a very slow release of the mix over the long term will be fine. As I said I've been using this method for donkey's years with no problems.
