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condensation in loft & cold rads

Postby neilfoley » Thu Dec 31, 2009 4:31 pm

Can anyone shed any light please..........we noticed condensation in our loft, with hot water running out of the expansion pipe, our rads downstairs were cold.

My heating engineer neighbour drained the system and ran a flush (inhibinter???) through, we had a few hours the next day where all the rads were hot with no hot overflowing water in the attic, with the pump on number 2 setting, but since then we can only get heating upstairs OR downstairs with the pump on number 3 setting and the hot water is pumping into the expansion tank again, the number 2 setting on the pump doesnt maintain the heat in the rads after being heated up by number 3......sorry im not the greatest at explaining

I cant work it out, its driving me crazy & Im really cold...... can anyone help??????

Regards Neil

PS happy new year
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Simply Build It

Postby rosebery » Fri Jan 01, 2010 12:00 pm

Pu,ping over is caused by a number of possibilities:

1. The system is piped incorrectly. Don't think it will be that or your heating engineer would have spotted it. It should be boiler - vent - feed - pump.

2. The vent pipe isn't high enough over the F&E tank.

2. Pump speed too high. Your post deals with that so rule that one out.

3. You've got a partiual but significant blockage that the flush hasn't shifted. Check where the feed pipe joins the primary in the first instance - thats the usual suspect. If you have a magnet run it over the pipework in that area (yes I know copper isn't magnetic but the magnetite that blocks your pipes is) and where it sticks theres the blockage. Flushing won't shift it - the affected pipework has to be cutout and replaced.

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