Expansion tank has hot water in it

[Pablo]

Hi

At the moment I only have my hot water on in the house (twice a day via the timer). I have noticed that the small expansion tank in the loft (as opposed to the big tank) has hot, brown water in it. Is it normal for there to be hot water in this tank? Any comments would be appreciated. Thanks

[John Stumbles]

On Tue, 06 Jun 2006 02:39:43 -0700, Pablo wrote:

No. Likely explanation is that water is being pumped over from the vent pipe - sort of inverted U shape with open end over the tank. This may only happen intermittently, when the pump first runs, or constantly (but I'd expect you'd notice the latter). First check that the water level in the tank is only about halfway up rather than full (bend the float valve arm down so that it only fills up to this level, and bail out water tolower it). Then check that the open end of the vent pipe no lower than about 1" below the rim of the tank: if it is then check whether it's come away from any supports meant to keep it higher and raise it if possible, otherwise trim back the open end. However there should be a rise of a foot or so from the top of the inverted U to the open end. The exact dimensions will depend on the topology of your system but that's a guide. If with all these factors correct you still get pumping over you may stop itby lowering the speed of the pump, but that's only a workaround: you should replumb it to avoid this situation. It may be worth going to a sealed system

your water will be well oxygenated by now I'd put in some system cleanser (e.g. Sentinel X400) and run that for a few days or weeks then flush out the system and refill adding inhibitor (e.g. X100). Make sure to bail out any crud in the header tank rather than allowing it to get drawn into the pipework.

[Chris Bacon]

Oh dear. It sounds as if it's pumping over. The brown is rust from the insides of iron on your CH system (radiators, boiler, etc.). It's possible, if everything else is OK, that the pump is set too fast. Get your central heating going, and see what comes out of the pipe leading into the top of the tank, the one that just ends in mid-air. Turn the pump down, if possible, and see whether that stops any water coming into the tank from the vent pipe referred to, and check that the rads. still get hot. The system may need draining/flushing, and an inhibitor would be a good idea.