Liebert Challenger Plus CP20A U Technical Data Manual page 7

In tro duc tion (con tin ued)
System types
Air cooled units
Air cooled mod els con sist of an evapo ra tor coil, a com pli ant
scroll com pres sor, high and low pres sure switches, an
ex ter nally equal ised, ad just able, ther mo static ex pan sion
valve, serv ice ports, re frig er ant line sight glass, liq uid
re ceiver with pressure- relief valve and fil ter drier. The units
are shipped with a hold ing charge of dry Ni tro gen.
Mod els CP20A, CP24A, CP28A, CP34A and CP40A are
sin gle cir cuit. Mod els CP26A, CP32A, CP42A and CP46A
are dual cir cuit.
Air cooled units re quire matched air cooled con dens ers. Fan
speed con trolled con dens ers are avail able from Lie bert for a
full range of out side am bi ent tem pera tures. Refer to the
Condensers Technical Data Manual (P/N SLE CD TDM) for
full details.
Fig ure 1 - Air Cooled Down flow Unit
SLE CP TDM E.1 (06/99)
Challenger Plus - Technical Data Manual
Wa ter/Gly col cooled units
Wa ter/Gly col cooled mod els con sist of an evapo ra tor coil, a
com pli ant scroll com pres sor, high and low pres sure
switches, an ex ter nally equal ised, ad just able, ther mo static
ex pan sion valve, serv ice ports, re frig er ant line sight glass,
fil ter drier, stainless- steel plate heat ex changer and a
head- pressure con trol valve (wa ter regu lat ing valve).
Pres sure re lief valves are fit ted down stream of the plate heat
ex changer. The re frig er ant cir cuits are pre charged with
re frig er ant in the factory.
Mod els CP20W, CP24W, CP28W, CP34W, CP40W are
sin gle cir cuit. Mod els CP26W, CP32W, CP42W and CP46W
are dual cir cuit.
The units op er ate with mains wa ter, cool ing tower wa ter or
wa ter in a closed cir cuit with an ex ter nal drycooler.
When op er at ing in a closed cir cuit, it may be nec es sary
(de pend ing on out side tem pera tures) to add mono eth yl ene
gly col to pre vent the wa ter freez ing in win ter, re fer to the unit
In stal la tion Man ual for ap pli ca ble per cent ages.
A pump is used to cir cu late wa ter (wa ter/gly col) through the
unit (not sup plied as standard).
If mains wa ter or tower wa ter is used, it is rec om mended to fit
a me chani cal fil ter on the wa ter line to pro tect the plate heat
ex changer against pos si ble im pu ri ties con tained in the wa ter
(for plate heat ex changer clean ing, re fer to the In stal la tion
Man ual).
Fig ure 2 - Wa ter/Gly col Cooled Up flow Unit
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