Central heating problems - from bad to worse

I've been working on a bathroom re-fit for the last few weekends. Last weekend, I removed a radiator and replaced it with a heated towel rail. This involved draining the system down. Sad to report that it's never been the same since.

The boiler started making a right old racket, thumping, banging and occasionally venting into the expansion tank. A phone call to a trusty plumber friend, and I'm pretty convinced that there is now some air in the system. Looking back I think this might have been caused by trying not too lose all the water in the system by turning off as many radiators as I could at both ends before draining down.

So this Saturday, I started to investigate.

The boiler is situated in a sort of utility room that links the house with the garage, and in the garage loft above there is a sort of pressure relief valve that I had trouble with last year when it started leaking. I wondered if this was adjusted down too tightly and was not allowing any air to escape, so up I went for a fiddle. DISASTER. The rubber o-ring is perished and, before I know it, the system is pissing out and dripping down into the wall mounted boiler below. A quick panic has me draining down the system again, and rushing off to B&Q to get a new o-ring. Once refitted, all seemed OK, until a couple of hours later I notice that the boiler is not firing at all, the whole system is off and the fuse has blown. To cut a further chapter short, the water from the leak has dripped down into the top of the pump that is sited under the boiler and cause the pump electronics to blow...... pump now f**ked. Another trip to Wickes this time for a new pump. Manged to fit that, but now one of the pump valves has a tiny leak from the screw that turns to isolate the pump. A common problem apparently.

Next weekend I'll be draining the system again to fit new pump valves.

The only good point about this is that the system does seems a lot quieter now.

I'm sure it's on borrowed time as the boiler is over 20 years old. Although I've replaced a boiler in the past, I wont be doing it again, so maybe this summer we ought to get it looked at?