Header tank steaming

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Hi. Does anyone know if it's normal for a header tank to be steaming? I turned the pump up recently to setting 3 to see if it would help heat our house better (a very long story), but the tank is now steaming and I am wondering if this is OK or not. The house is lovely and warm now so I'm not keen on lowering the pump setting if this is only a minor concern, although the condensation on the liner and rafters above the header tank is worrying me a little, but I guess I could just try and seal in the moisture with a cover? The pipe going into the tank is dripping slightly too.
 
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No you have a problem.
Turn the pump speed down to 1 to see if this is any better.
Otherwise needs the plumbing looking at.
if possible convert it to a sealed system.
Vented systems have no place in a modern heating system it's technology from the dark ages.
 
The problem you have is called pumping over and is usually caused by sludge in the system blocking the flow from the boiler to the rads and the only escape for the hot water is via the overflow into the header tank.

It can be an easy fix but depends on your level of confidence and competence with heating systems.
 
No you have a problem.
Turn the pump speed down to 1 to see if this is any better.
Otherwise needs the plumbing looking at.
if possible convert it to a sealed system.
Vented systems have no place in a modern heating system it's technology from the dark ages.

Thanks. I was hoping that wasn't the solution :( as our house was freezing on setting 2 let alone setting 1. Do you know if it is damaging to the system to leave it as it is? In response to kbdiy, what is the easy fix you are referring to?
 
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You need to locate where the cold feed from the header tank joins the flow pipe from the boiler. Test with a magnet to see if it sticks. Likely as not it will which indicates a build-up of magnetite. This is the sludge causing your problem.

You might be able to flush it out but you will need assistance and a wet vac. Turn everything off and close the pump valves so nothing can pass through. Then push a hosepipe as far as possible up the expansion pipe over the header tank. Isolate the supply to the header tank so it doesn't fill. Vacuum out all the water in the header tank. Here's where you need an assistant - hold the hose firmly in the expansion pipe and give it a blast with mains pressure water. This MIGHT force the blockage back up the fill pipe into the header tank with all the muck. Vac it out and repeat until it is just clear water. If successful then open up the pump valves, dose the tank with a bottle of corrosion inhibitor and let it fill again. Then test for circulation through the heating system.

If that doesn't work you may have to partially drain down and cut out the blocked section of pipework. The above process worked a treat for me and I went on to do a complete chemical clean on the whole system when the weather was warmer.
 
If there is magnetite present, it usually forms a hard crust around the pipework (as well as the loose stuff that can be flushed as described above). Cut out and clean or replace the pipework then reassemble. Set pump to speed 2 and check that it isn't pumping over again.

The pumping over is circulating oxygenated water around the system allowing corrosion to take place more readily.

James.
 
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Typically this is where I would start looking. That is a representation of pipe layout, yours may differ somewhat. Check also for blockages around pump and pump valves and all CH pipework in airing cupboard.
 
Yes it will harm the system it's letting air enter the system meaning more sludge will build up and make the system worse.
 

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