Closed System Chemicals

Closed circuits and closed loops that employ water as a primary medium are used extensively in many commercial, manufacturing and industrial process activities.

Closed System Chemicals

To ensure that such closed circuit heating systems are well maintained and operate at optimum efficiency it is essential that the correct water conditions are maintained at all times. This can be achieved using carefully selected closed circuit water treatment chemicals.
Accepta’s comprehensive range of high performance cooling water treatment chemicals have been scientifically formulated to deliver significant operational benefits and performance improvements to cooling towers, and open and closed cooling systems that use water as a primary coolant.

If you are a water treatment specialist, FM or maintenance company who regularly resells water treatment products to your customers why not apply to become an Accepta Registered Reseller.

Accepta’s advanced closed loop and closed circuit treatment chemicals have been scientifically formulated to deliver significant operational benefits and performance improvements to heating systems and closed circuit systems including sea water cooling systems, closed chilled systems, low-pressure heating systems and other closed circuits that use water as a primary medium.
Our extensive range of high performance closed loop treatment chemicals include anti-foulants, specific corrosion inhibitors, multi-functional scale and corrosion inhibitors, and anti-freeze and de-icing products for frost protection applications.
Closed System Biocides

The accumulation of microbiological slimes, biofilm and general bio-fouling in closed circuit water systems can be problematic. The build-up of such unwanted foulants can reduce system efficiency, and increase operating and maintenance costs.

See Products

Pre-Commission Cleaning Chemicals

For use cleaning or renovating closed and open heating systems.


Pre-Commission Cleaner for Closed Heating & Cooling Systems

Non-acid blend of sequestering and dispersing agents

Protection of Copper & Alloys During Cleans

Supplementary Azole Inhibitor to provide greater protection of yellow metals

Pre-Commission Cleaner for Closed Heating & Cooling Systems

NTA / HEDP Based Cleaner


Pre-Commission Cleaner for Closed Heating & Cooling Systems

NTA / HEDP based Cleaner with Polymer

Closed System Chemical Dosage Form

Complete as much of this form as possible to get your bespoke closed-system chemical treatment recommendations.

Closed System Terms & Functions

LPHW – Low Pressure Hot Water Systems

LTHW – Low Temperature Hot Water Systems

The above terms are interchangeable and refer to system operating up to about 90oC and pressures of about 3-4 bar.

MPHW – Medium Pressure Hot Water System

MTHW – Medium Temperature Hot Water System

The above terms are interchangeable and refer to systems operating between 95oC and 115oC and pressures about 5-8 bar

HPHW – High Pressure Hot Water System

HTHW – High Temperature Hot Water System

The above terms are interchangeable and refer to systems operating above 120oC and pressures of 10 bar or greater.

Chilled Water – A system circulating water below about 8oC cooled by a refrigeration or chiller plant. Chilled water systems may operate below 0oC being prevented from freezing by the addition of glycol, alcohol or brine as an antifreeze.

Condenser Water – A circuit taking water away from a refrigeration plant to a separate heat rejection device eg. a cooling tower (temperature typically 20-40oC). Condenser water can either operate by an open circuit (where water goes directly over the cooling tower) or a closed circuit which loses heat to a heat exchanger or another open circuit.


Closed System Water Analysis

Our Head Office is fortunate to have an onsite chemistry laboratory which is involved in the quality control process of our closed system chemicals, this laboratory also performs water analysis on closed loop water samples from our customers in the UK and is available to order online with packages including:

BSRIA analysis is an all-encompassing analysis including a set of microanalysis and a full suite of chemistry tests and is an ideal analysis to have performed 3- 6 months after first commissioning your system. For the Standard closed system analysis, the list of parameters includes:

  • pH
  • M. Alkalinity
  • TDS
  • Nitrite
  • Tannin
  • Molybdate
  • Phosphate
  • Glycol % (if type known)
  • Iron
  • Aluminium
  • Copper
  • (Ammonia by request)

Performing analysis regularly is important to keep on top of your closed system water treatment levels as poor management can lead to scale & corrosion issues, reduced efficiency and even damage to critical systems. Ordering online is simple as Card and BACS payments are accepted, the lab will send out a Freepost returnable sample kit and provide a report of results soon after.


Chemical Dosing Pots

Dosing pots are required in order to feed liquid chemicals such as corrosion inhibitors & biocides into closed systems.

The dosing pot consists of a stainless steel vessel with inlet (return) and outlet (flow) valves, a drain valve and a filling valve.

A stainless steel tundish, air release and non-return valve.


  • 3.5L Dosing Pot operates at 14 bar
  • 6L Dosing Pot operates at 14 bar
  • 13.5L Dosing Pot operates at 10 bar

Additional sizes up to 25L are available on request. Contact us for a quote.

Ready to talk about water treatment?

Contact us

Please complete this form and we will be in touch