on the wet b ulb vacuum indic ator. At thi s temperature/p ressure, isolat ed pockets of mois-
ture can turn into ice. The slow rate of evaporatio n (sublimation) of ic e at these low temper-
atures/pressure s greatly incr eases dehydration time.
5. Valve off the vacuum pum p , stop the pump, and reco r d th e instrument reading.
6. After a 2-hour wait, take another instrumen t rea ding. If the reading ha s not changed,
dehydration is comp let e. If the reading indi c at es vacuum loss, repea t St eps 4 and 5.
7. If the reading contin ues t o change after severa l at tempts, perform a leak t est up to the
maximum 180 psig (1241 k P a) pr e ssure. Locate and rep air the leak, and repeat
dehydration.
Inspect Water Piping
Refer to piping diagrams prov i ded in the certified drawi ngs, and the piping instru c ti ons in the
17/19EX Installatio n Instructions manual . Inspect the pipin g to the cooler and condenser. Be
sure that flow direct ion s are correct and that al l piping specificati ons ha ve been met.
Piping systems must be properly vented, with no stress on waterbox nozzles and covers.
Water flows through th e c ool er and condenser must m eet job requirements. M eas u re the
pressure drop across c ool er and across condense r.

Click here f or Figure 29 — Dehydration Cold Trap