Specialist Topic
Microbore Heating Problems
Microbore systems use narrow pipework that is especially vulnerable to sludge, restriction and circulation failure.
Microbore heating systems were popular for many UK homes because narrow pipework is faster to install and easier to route. However, that same narrow internal diameter — typically 8mm, 10mm or 12mm — makes microbore systems particularly vulnerable to contamination problems.
Why Microbore Systems Restrict So Easily
Even a relatively small amount of magnetite sludge or corrosion debris can occupy a meaningful percentage of the internal flow area in microbore pipework. As deposits accumulate, hydraulic resistance rises sharply, water flow drops and radiators stop heating evenly.
Common Microbore Symptoms
- radiators that warm slowly or only partially
- cold radiators on one side of the property
- noisy pumps under load
- poor heating recovery after the system has been off
- repeated need to bleed radiators
Why Conventional Power Flushing Has Limits in Microbore
In moderately contaminated microbore systems, a careful conventional power flush can help restore circulation. In heavily blocked microbore systems, the same narrow pipework that caused the problem also limits how effectively cleaning solution can be circulated through the restriction.
When PowDer Flush may be appropriate
Honest Microbore Diagnosis
Microbore systems need careful assessment. We look at the symptoms, the system layout, the boiler condition and the apparent contamination level before recommending a course of action. Sometimes a cleaning service is the right answer; sometimes the realistic answer involves more significant work.