F&E tank lids

[chrisw99]

Back in August I flushed out my system after 4 weeks of using Sentinel X400, drained and refilled several times until the drain water was totally clear, refilled with the correct amount of Sentinel X100 inhibitor and left it.

I was in the attic at weekend and noticed the F&E tank which was totally cleaned out 2 months ago now has a thick brown sludge about half an inch thick all over it like a custard skin. The water in the tank is dark brown. I did open the drain cock at the boiler for a second to have a look and that water is still clear.

There's never been a proper lid on it, just a makeshift one out of polystyrene, with a 2 inch diameter hole cut in it so any water coming out of the expansion pipe can go back in.

When googling about gunk building up on the surface, I've read I should have the tank sealed with a lid, but how does that work when there is an expansion pipe looped over and ending about 3 inches above the surface of where a lid would be??

And this gunk never built up in the 15 years prior to me refilling the system with the same setup of polystyrene lid, so what has occurred in just 2 months??

 

[JohnD]

you make a hole in the lid for the vent pipe. If the pipe is too short, add a plastic funnel, or lengthen the pipe.

you most likely have fungus in your tank. Another common problem is clear bacterial slime. Don't drain the system until you have cleaned the F&E, or the contaminants will run down into the system.

Tie up the ball float, bale it out into a bucket, sponge it clean, wipe round the entire inside of the tank (and the new tightly fitting lid you are going to buy) including the float, arm, valve and overflow pipe, with bleach.

Then go and order a bottle of Fernox Biocide AF10 and apply it according to instructions.

While you are buying your new lid, buy an insulating jacket for the F&E, and some pipe lagging. It is not, as many people think, to prevent the tank freezing in winter. It is to protect it from excessive heat in summer when the sun beats down on the roof and turns the water into a warm biological broth.