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Microbore system problems

Postby testab » Wed Jun 25, 2008 2:32 pm


I have a microbore system with 6 upstairs and 5 downstairs radiators. 2 upstairs radiators did not warm up at all and 1 was warm at the top and cold at the bottom (maybe needs flusing). 1 of the downstairs radiators had the bleed screw broken and could not be I was advised that it may be due to sludge, so drained the system. I put some sludge remover in the loft feed tank and run the heating for 8 hours. 2 weeks later, I drained the system again (from all 5 downstairs radiators as each one had its own drain cock).

Now all downstairs radiators are not working and only 2 upstairs ones work. Is that a result of the downstairs radiator that could not be bled? Do I need to replace this radiator first and then drain the system again?

Thanks in advance for any help.
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Simply Build It

Postby thedoctor » Wed Jun 25, 2008 3:29 pm

Go to our DIY Projects section and look at the central heating projects. All radiator problems are explained in there.
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Postby plumbbob » Wed Jun 25, 2008 11:08 pm

Maybe the system just needs balancing. See the projects section.
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Postby htg engineer » Thu Jun 26, 2008 2:04 pm

With you draining the system - it points to an airlock.

Make sure all radiator valves are open and all radiators are full, no air or water ? remove vent nipple and insert a pin - they do sometimes become blocked.

Turn off the radiators that are heating, and turn the pump speed up if possible. This normally clears air, from a radiator or two.

If not, or if one doesn't heat - turn off all radiator except the problem radiator and see if it pushes thorough.

Once all radiators are heating - vent again - with heating turned off.

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