Thermo NESLAB HX 150, Service Manual

Page: 43 / 51

43
Tank Coil Assembly (TCA) repair
A hole occurring in the evaporator may be repaired, provided
the hole is accessible and the capacity exists to weld stainless
steel. A bead of weldment can be placed over the hole. The
most practical method may be to remove the TCA as outlined in
the “Tank Coil Assembly (TCA) replacement” procedure, and
take the TCA to a local welding shop. Advise the welder the coil
is type 304 stainless steel.
If the hole is inaccessible, or no welding capability exists, the
entire TCA should be replaced.
Tank coil assembly failure
A hole developing in the evaporator of the Tank Coil Assembly
can cause serious problems if not detected quickly. Once a hole
occurs, refrigerant will escape into the circulating fluid. Once the
refrigerant is exhausted, circulating fluid will be drawn in and
contaminate the refrigeration system.
A hole in the evaporator may be recognized by a stream of
(refrigerant) bubbles coming to the surface of the circulating
fluid in the tank. If this is observed, it is vital to immediately shut
the system down and drain the circulating fluid until it is below
the level of the leak. This will prevent fluid from being drawn into
the refrigeration system.