Two days before Christmas my wife turned on the shower to find that only a dribble of cold water came out. Now, we're in the middle of a major house renovation and the old combi boiler has been dying for some time. A brand new Eco-hometec boiler is sitting in a box in what will be the kitchen so we didn't want to spend any money keeping the old boiler going.
So we decided to strip down the boiler and have a go at repairing it, after all IF we could find someone to repair it, it would probably cost a fortune, so we got out the instructions and set about removing the heat exchanger as we were pretty sure it had become furred up as we live in a hard water area.
First we removed the expansion vessel and then the exchanger itself and as we suspected it was COMPLETELY blocked. A trip to the supermarket later and we had three packets of kettle descaler which we manageed to dribble into one end of the exchanger. Some fizzing ensued and we got a bit more in. Eventually we managed to get some descaler to go right through and come out the other end and at that point we jammed a funnel on end and filled it up with descaler. Three pints later and water was gushing through so we put it all back together and turned on a hot tap.
For a few brief seconds a familiar trickle of water came out and just as we cursed a huge flow came out of the tap followed by a puff of smoke or dust and then nothing.
We decided that we must have dislodged a lump of scale which had moved and was blocking somewhere so decided to strip the boiler again and try to find the blockage.
This time we didn't remove the expansion chamber as we were able to get at the heat exchanger because we'de removed the side of the boiler earlier - BIG MISTAKE. When we pulled out the heat exchanger masses of warm water pissed out of the back of the boiler going EVERYWHERE.
Undeterred we checked the heat exchanger and found it was fine. We knew water was getting to the boiler and we knew that water could flow through the heat exchanger so we deduced that the pipe between the boiler output and the tap must be blocked.
So we cut the pipework and replaced it with new and re-assembled the boiler and turned on the hot tap. Loads of water came rushing out - how we cheered - until we realised that the boiler wasn't firing and the water was stone cold.
Using the fault finding guide in the instructions we narrowed the fault down to on of the boards in the electronic part of the boiler so we opener the flap to discover that is was very wet in there. No wonder it didn't work. 20 mins of hairdryer later and we turned on the power and opened the hot tap again and HOT WATER came out. loads of lovely hot water better than it's been for at least four years.
So the moral of this story is - if you have nothing to lose you might as well have a go and D_I_Y.
Nick
PS without the helpful advice from this group I'd never have had the courageto open up the boiler but I'm very glad I did as I saved a fortune AND had water for Christmas