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Repairs for Inefficient and Faulty Central Heating Systems

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Every winter GASLEC engineers are called to repair lots of central heating systems and radiators that won’t get hot. Cool radiators are often associated with a boiler that’s overheating, cutting out or breaking down.

However, the cause of the problem is often dirty system water, meaning the heating system is becoming blocked-up with sludge – a black, mud-like deposit referred to as ‘magnetite’. Magenite is caused by iron oxide (the result of combining water, air and iron) that builds up on the inside of a poorly maintained boiler and heating system.

For many Landlords and Home Owners, having cool radiators and a boiler that keeps breaking down signals a call to GASLEC. In extreme cases, a boiler manufacturer will refuse to continue offering a warranty until the sludge / magenite has been removed – to prevent further damaging the boiler.

Years ago, this would have been a time-consuming problem for us to fix: and expensive. Until recently, the technical fix would have included fitting a dirt separator and filter which, as it suggests, collects dirt in a basket filter.

The Latest Technology

But today, we use the very latest technology and a product called MagnaClean.

MagnaClean is a magnetic filter that we fit to a heating system to remove the excessive build-up of magnetite and prolong the life of the boiler and heating system.

This clever filter works by using strong magnets to collect and remove small pieces of iron and metallic sludge (magnetite) from the heating system.

Tests over a twelve-month period comparing using a MagnaClean magnetic filter with a traditional dirt separator and basket filter showed the MagnaClean unit was up to 80% more effective at capturing the damaging magnetite system sludge.

Here’s The Technical Bit

Here’s the technical bit

Test results as reported in Installer magazine showed that a 50mm MagnaClean filter collected 1.52kg of magnetite during a two-hour cycle at a flow rate of 27m3/hr.

By comparison, a 50mm basket filter with an 80-mesh basket collected just 0.02kg and a comparable dirt separator collected 0.31kg of magnetite under the same flow conditions. The results speak for themselves.

Once collected, the magnetite did not wash off the MagnaClean filter even at greater flow rates than the test rates, further reinforcing the case for magnetic filtration over these alternative and we think outdated system protection methods.


Here is how we go about fixing a heating system that’s blocked-up with sludge.

We follow a four-stage process:

  1. Clean out the sludge from the system, that’s causing the problem.
  2. Fit a Magnacleanse magnetic filter to remove metallic particles from the system that if left in the system could cause excessive wear to the boiler and pump.
    1. We need to alter the pipework to accommodate the Magnacleanse magnetic filter unit that will be fitted temporarily, to remove metallic sludge from the heating system
    2. We connect the Magnacleanse filter to the new pipework, add a heating system cleanser, refill the heating system and run the boiler to its operating temperature.
    3. We then isolate all radiators except one and flush the system – one radiator at a time. This process is repeated until all radiators have been cleaned.
    4. Remove the Magnacleanse magnetic filter, re-connect the heating system pipework and remove the metallic sludge from the customer’s premises. (To be disposed of professionally).
  3. Install a new system filter, corrosion inhibitor and refill the system.
  4. Carry out a full heating system-check to be sure it’s working efficiently.

The result? A quieter boiler, radiators that heat up properly and a boiler manufacturer’s warranty that’s valid.

Case Study

We’ve produced a case study below, that includes images of a recent call to a heating system in Exeter, Devon in December 2016 in need of repair.

We were called to repair a central heating system that wouldn’t get hot. Previously, the boiler had broken down several times within its warranty period and the manufacturer’s service engineers had visited the home owner to fix the problem.

The boiler frequently overheated and cut-out. Not all radiators were heating up as they should.

The manufacturers engineers noticed the boiler plate heat exchanger was blocked up with sludge and replaced the unit on two separate occasions.

On the most recent visit, the manufacturers engineers explained that because the problem was dirty heating system water the manufacturer would not cover the warranty until the system had been cleaned and a magnetic system filter fitted.

Finally, GASLEC were called to fix the problem.

Our heating engineers quickly drained the system and altered the heating system pipework so that a to accommodate a magnetic system filter.

We connected a MagnaClean magnetic filter to the new pipework, added cleanser to the system water, refilled the system and ran the boiler.

All radiators except one were isolated and we then flushed the system one radiator at a time. This image shows the substantial amount of sludge that came out of just one small radiator, there were thirteen on this system and all had similar amounts of sludge / magenite that the magnetic filter removed.

When our engineers were satisfied that all the radiators were clean, they opened all radiator valves and flushed the system until no further deposits were collected by the MagnaClean magnetic filter.

We then drained the system again, disconnected and removed the MagnaClean, installed a brand new new system filter, added a corrosion inhibitor, refilled the system and thoroughly tested the heating system to GASLEC standards.

The Home Owner now enjoys hot radiators, a warm home and has a quieter, more efficient boiler. We were pleased to learn that the boiler manufacturer has reinstated the boiler warranty.

The post Repairs for Inefficient and Faulty Central Heating Systems appeared first on Gaslec Exeter – Plumber, Electrican & Gas Engineers.

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