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An easy to apply solution for curing inaccessible leaks in both vented and sealed central heating systems, in less than 24 hours.

When heating and cooling systems are known to have a small leak, the obvious solution is to tighten the joint or replace pipe work.

However, when the location of the leak cannot be found, or is suspected to be in an inaccessible area, such as under floorboards or in wall spaces, the work required to make good is likely to be lengthy and expensive.

Long term leaks can cause severe damage to floors, floor coverings and ceiling, and it is important to prevent the leakage as quickly as possible.

Sealed heating systems will often fail as a result of system pressure loss, as many modern boilers require a minimum 0.5 bar pressure to fire at all. Loss of pressure in sealed systems, and the consequent need to frequently re-pressurise, is often the first indication of a leak.

SYSTEMSEAL is a simple and economical answer to the problem.

SYSTEMSEAL is a white emulsion polymer that is added to the system and allowed to disperse throughout by the normal pump circulation.

Once SYSTEMSEAL has found and penetrated the leak the presence of air causes the polymer to set into a flexible seal, preventing the loss of any more water.

 SystemSeal leak sealer


Application & usage:

Add SYSTEMSEAL to the feed and expansion tank of the system after isolating water supply and draining off 15 litres of water.

Allow system to refill to ensure leak sealer enters main body of system. Alternatively a SYSTEMSURE injector may be used to inject SYSTEMSEAL into a radiator through the air bleed valve, or via a filling loop.

Switch on system and allow SYSTEMSEAL to circulate for at least one hour for even distribution, preferably with the boiler firing.

Most leakages should be cured within 24 hours, dependent on the location of the leak and the rate of leakage. If a substantial amount of water has drained from the system, check, and if necessary, add more SYSTEMSAFE-DM corrosion inhibitor to bring treatment to required level.

Correct dosage: 1 litre of SYSTEMSEAL is sufficient to treat a system with up to 12 radiators. Add more SYSTEMSEAL in proportion for larger systems.

N.B. If system has a thermal store, add extra SYSTEMSEAL to allow for the extra volume of primary water in the cylinder.

Click below to download the full data sheet/instructions (PDF)

Click here to download the full data sheet/instructions

Available in:

  • Cartons of 12x1 litres (BSS002)
  • Cartons of 4x5 litres (BSS003)
  • 25 litre drum (BSS004)
  • Technical data:

  • Appearance: white liquid emulsion
  • Odour: Slight
  • S.G. at 20°C: ca. 1.0
  • pH: 7
  • Solubility: completely miscible in water
  • Boiling point: 100°C