Closed Loop Doctor

Chilled Water Loop


The chilled/closed water loop transfers heat between AHU/FCU and the chiller. The term “closed loop” seldom means that the chilled water is free from contamination or bacteria. Depending on the incoming water, minerals will deposit in the system over time. Bacteria are present everywhere and can also enter the closed loop. Thus it is important for chilled water systems to be commissioned and treated well, aiming to prevent loss of heat transfer due to fouling, scale or corrosion, and aiming to prevent damage to major equipment such as AHU/FCU, sensors, thermometers, motorized valves and pumps.  Although the low temperature is not conducive for Legionella bacteria, other bacteria including iron bacteria still prevail. Therefore, sufficient care has to be taken to ensure occupants’ health and reduce the corrosion risk.

Chilled Water Loop Recovery Program

Our Services

Photo: Chilled water samples, from left to right: before, during and after our Clean CT-01™ Rehabilitation program

The Steps

The chilled water loop rehabilitation consists of the following main steps:

  1. Flush system to remove dissolved and suspended impurities
  2. Connect mobile sidestream filtration skid and start filtering out any suspended impurities still present inside the loop water
  3. Dose Clean CT-01™ non-toxic low-pH descaling agent. For certain period, maintain level of active reagents; confirm by monitoring relevant chemical concentrations. During this time, the majority of rust and scale gets removed. Monitor filters and replace when clogged
  1. Flush system to remove dissolved impurities
  2. Dose Clean CT-01™ Pipe Cleaner which raises the pH above 7. For certain period, maintain level of active reagents; confirm again by monitoring as before. Still remaining rust and scale gets removed, while cleaned metal surfaces are being protected with ultra-thin corrosion-inhibiting passivation layer. Monitor filters and replace when clogged.

Photo: Generic filter cartridges such as the ones shown remove huge amounts of impurities throughout the process, reducing the requirement for aggressive chemical concentrations that could be damaging to the system. Photo on left shows also one clean cartridge for comparison

Ongoing Treatment

Maintenance Service

The Clean CT01™ Chilled Water treatment System for ongoing treatment comprises of side stream filtration, wetting agent and non-toxic food grade chemical. Where necessary, also a pre-treatment of incoming water is incorporated. The treatment system is designed to firstly commission the chilled water system by removing major impurities, protecting the wetted surfaces and stabilizing the water quality. Upon stabilization of the water quality, only routine monitoring (once every 1 to 3 months) is required. As water loss from AHU/FCU maintenance and evaporation will be replaced by fresh incoming water, annual re-commissioning is recommended to keep the water system at stable conditions for maximum protection of the system’s health. This green technology uses only safe ingredients that are either approved food additives or cleaners of food-preparation surfaces.

This service is provided by our own GLWC water treatment experts.

Note: If you are a service provider and are interested to render this service to your clients, please enquire about becoming a regional representative.

Please contact us to obtain pricing or request further details.

Photo: generic cartridge filters are used to filter impurities from the water

Photo: Sidestream filtration including chemical feeder set-up for a chilled water system

Photo: Schematic set-up for chilled water filtration skid plus chemical (pot) feeder

One-off water system clean-up service

Our experience in cleaning pipes is relevant also for other circulating water systems, such as cooling tower (condenser) systems, boiler loops, drinking water supply pipelines and more. As with all Clean CT-01™ products and services, dirt such as rust, scale and biofilm will be removed leaving behind corrosion-protected inner loop surfaces. This green technology uses only safe ingredients that are either approved food additives or cleaners of food-preparation surfaces.

Please contact us for more information and to request a quote.