Plumbing #3 – blocked feed pipe

As I mentioned in my previous post, when I went to refill the central heating system with water, the water in the header tank just stayed there. Here’s a picture of the tanks in the loft.

The cold water tank is the big one at the bottom of the picture. The metal cuboid one in the middle is an old tank that has been left there as it is too big to go through the loft access hatch.

I have highlighted the central heating header tank.

I had to take a step ladder up into the loft in order to reach the tank. Here’s what I saw when I got there.

There was no cover on the tank, just a bit of plastic partially covering the top. As you can see there was a lot of iron oxide deposits. A bad sign since this means that the system was full of sludge and oxide and this was what was causing the blockage.

I had some powerful neodymium magnets and these were useful in tracing the blockage as they don’t attract the copper pipe, but do attract the iron oxide and black sludge full of iron bits. I found that the blockage was at the “T” where the 15mm feed pipe joins the 28mm immersion return to the boiler.

I tied up the ball cock and started bailing out the water with a plastic bottle. I then used some newspaper to mop up the worst of the sediment.

Next I went the “T” and used a 2mm drill bit to make a hole to drain the water in the pipe. There was a big orange spray as I pierced the pipe. Luckily, I cut the top off the bottle to make a handy container to catch the water. Once it was drained, I worked out what I was going to cut, and then got my junior hacksaw and started sawing.

This is what I saw ( after sawing ). As you can see the pipe is completely blocked with crud.

Here’s a closer view.

Once I cleaned out the pipe, I reconnected the pipes. Job done. Now the filling of the system can take place. I flushed the system through with several changes of water, and then poured in some central heating system cleaner and left it overnight. The next day I flushed through and then added the inhibitor. I think I’m going to invest in a MagnaClean when we get a new boiler to protect our investment. Also later next year ( in the summer ), it might be worth taking radiators off and giving them a flush with a hose. Or we might invest in some new radiators. The standard ones you get now have fins to increase the amount of heat given off.