HVAC Chemical Flushing

<...execute chemical flushing for chilled water pipes and coils , what chemicals can be used , chemicals concentration,and procedures step by step....>

It depends upon what the problem is, and the materials-of-construction of the pipework, fittings, joints, etc.

<...chemical treatment for makeup water to protect pipes and coils against rusting and precipitates formation...>

Contact a reputable water treatment chemicals specialist. Nalco (usual disclaimer) springs to mind; there are others.

majority of pipes materials and fittings are copper and all coils and evaporators also.

our problem is partial blockage for water pipes and chilled water coils with a mineral deposits, it's hard to remove , it reduces heat transfer between chilled water coils and air stream in FCU .

Usually Chilled water, used for A.C applications, is a closed water system. If treated water is used dosing of chemicals as per the recommendations of water treatment experts should be a part of the system. Chemicals like Corroban (Number I do not remember) are used for dosing.

Any of you have an idea about Chemical cleaning / flushing of HVAC ducts with oil, grease and dust..?

Sincerely

NADCA (USA) is registered society to qualfiy the companies to carry out HVAC duct cleanings as per the standards, you can get more details form the NADCA wwb site. Regards

Dear Friend,

You need to know the raw material of condenser tubes, capacity, water quality, type of scales, whether condenser has facility to pump in chemical for cleaning the tubes.....

Different chemical manufacturer (even local manufacturer) prepares variety of chemicals to clean the tube, pipes. Reputed suppliers are GE and Nalco. You need to call chemical solution supplier, hand over the scales and ask to supply the chemical with guarantee to remove scales with out damaging the condenser material.

Select non chemical based equipment for maintaining the cleanliness. There are few manufacturer manufacture the units, Check www.ecospec.com or www.dolphinwatercare.com or you can visit www.eco-web.com and find out the company in your country.

Chemicla flushing is carried out for three reasons.First to remove internal corrosion and debris of pipe during installation(ie pressure testing and draining will cause corrosion).second to control corrosion in future.third to control the fugus and bacterial development inside the pipes.Chemical names are always recommended by third party chemical agent.He has to be appointed and he will supervise the MEP contractor for the same.First step of flushing is gravity flushing.All valves of higher diameters(mainly riser) to kept open remaining should be closed.Water should fed at top point of circuit through domestic waterpump or gravity.At same time same quantum of water should drained at lowest part of circuit.This should be carried out until sample water at drain point is free from any debris and dust.Then the system valves except all coils should be open.Chilled water pump should be switched on and water should circulated throught out the system except coils.Mean time all strainers should be cleaned.While circulating water fresh water should be added to system from highest point and same quantum should be removed at bottom.Once water comes clean anticorrosive chemical should be added according to system volume content and it is allowed to circulate to all pipings except coils without any additioning or draining of waters.This should be carried up to 48hrs.Once this completed then New water should added to system until iron content of system reaches 1 ppm.After this corrsion inhibtor and antifungal chemical should added and circulated for 8 hrs.