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  1. #1
    Join Date
    Jun 2011
    Location
    Moscow, Russia
    Posts
    9

    RTHC Chiller Evaporater End plate pitting

    I just pulled the Heads off of the evap side and found some really bad pitting approx 1/4" deep. How thick is the steel on the tube bundle end plate and will Pro-Poxy 20 solve my problem?

  2. #2
    Join Date
    Sep 2011
    Location
    BAJA AND CALIFORNIA
    Posts
    90
    the steel end sheet is aproximate 1.5 inch and the bundle depend on the unit but almost 1/2 inch or less , apply epoxy coating is the best under the following procedure also recommend make eddy current test if the unit have more then five years on both bundles evaporator and condenser .
    please read epoxy application below:
    THE EPOXY PROCEDURE

    * set up air compressor and thoroughly blow all tubes completely dry.

    *Visqueen is spread out to protect the immediate area and surrounding equipment from dirt and debris.

    *Using a process, the Vacu-blaster is put to work removing all rust, scale and buildup from the metal surfaces to a clean white metal SSPC-SP10.

    *All cleaned surfaces are heated to draw out any additional moisture before the epoxy is applied.

    *Each mixture application is applied by hand to all treated surfaces to a minimum dry thickness of 50 mils in several coats.

    *All eroded areas and division plates are built up and refitted to accommodate new gaskets.

    *Upon completion and setup of the epoxy (normally 24 hours) lightly sand the gasket areas and chase all threaded bolt holes or studs to remove any residue epoxy.

    *All tube ends are cleaned out and blown free of any debris.

    *All spent material is picked up and the equipment room area returned to a clean condition.

    *Electronic spark testing is used on request to find any pinholes in the finished product and repairs made if necessary.

    hope help regards

    oscar

  3. #3
    Join Date
    Jan 2012
    Location
    Perth Down Under
    Posts
    26
    So what is the cause of the corrosion? Is there any water treatment in the chilled water circuit. If little or none you will need more than expoy to protect the tube sheet. Try adding anodes to the waterbox at each end. Mount the anodes on stainless threaded rod tapped into the edge of the waterbox. We do this in our country on all condenser waterboxes after they have been coated in ceramic epoxy.
    The corrosion is cause by mostly electrolysis and a small amount of bad water. The coating protects the tube sheet and waterboxes, the anodes are there to be attacked. It is easier to replace anodes than it is to replace the chiller. Same principle as you have on the hull of a large boat

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