Emerson Fluid Chiller Guía para resolver problemas descargar pdf (Pagina 70)

Problem Causes Corrective Action

Compressor tripping on Internal Thermal

Protector - Fails to Start-Up and Run Long

Enough to Pull Down Temperature

CPR setting too high

Re-adjust the CPR to a lower setting - see

adjustment procedure

Valve Fails to Open

CPR setting is too low

Valve defective - bellows leak, pressurizing the

upper adjustment assembly

Replace valve

Table 3 - Refrigerant lbs. per ft.*

Refrigerant

Condenser Tube Size - O.D. (in inches)** and Ambient Temperature ° F

3/8" 1/2" 5/8"

40°0°-20° -40° 40°0°-20° -40° 40°0°-20° -40°

R134a.051 .054 .055 .057 .095 .099 .102 .105 .150 .157 .164 .167

R22.051 .054 .055 .056 .094 .099 .102 .104 .150 .159 .163 .167

R404A/R507A

.053 .056 .0 58 .059 .098 .104 .107 .109 .157 .166 .171 .175

Problem Causes Corrective Action

Low Head Pressure During Operation

Val

abl

e t

throttle "C" port

ial wedged between "C" port

seat and seat disc

2. Power element lost its charge

3. Insufficient winter-time system charge

all

y r

e head pressure and tap valve

body to dislodge foreign material

2. Change valve

3. Add refrigerant per Table 3

Wrong charge pressure in valve for refrigerant Change valve

Receiver exposed to low ambient conditions is

acting as condenser

Insulate the receiver

ot gas bypass line restricted or shut off Clear obstruction or open valve

System Runs High Head Pressure

-or-

Cycles on High Pressure Cut-Out

Compressor not pumping, restriction in liquid

line, low side causing very low suction pressure

Change or repair compressor; clear obst

ruction

or other reason for low suction pressure

onden

ser

fan

not

runnin

g or

tur

nin

g in w

ron

direction

Rep

lace

or r

epair

fan

moto

r, be

lts

, wir

ing

controls as required

Fan cycling

Run condenser fan continuously while system is

running

Pressure drop through condens

er exceeds

allowable 20 psi f

orcing "B" port partially open

Repipe, recircuit, or change condenser as

req

uired to r

educe co

nden

ser pre

ssure

drop to

less than 20 psi

Condenser undersized or air flow restricted or

short circuiting

Increase size of condenser or remove air flow

restriction o

r short circuit as required

"B" port wedged open due to foreign material

between seat and seat disc

Artificially reduce head pressure below valve

setpoint and tap valve body with system running

to dislodge foreign material

"B" port seat damaged due to foreign material

Change valve

Wrong charge pre

ssure in valve for refrigerant

Excessive system charge or air in system

Purge or bleed off refrigerant or non-

conden

sables as syste

m requ

ires

Obstruction or valve closed in discharge or

nden

ser

drai

n li

Clear obstruction or ope

n valve

Liquid line solenoid fails to open

Check solenoid

Troubleshooting Head Pressure Controls

CHARGING THE SYSTEM - THEORETICAL METHOD

Weighing the Charge (Method has practical limitations)

Add refrigerant until the sight glass is clear and free of bubbles.

Determine refrigerant required to ll the condenser, see Table 3 below. Add this additional amount.

* Return bends: 3/8” O.D. - 20 ft; 1/2 O.D. - 25 ft.; 5/8 O.D. - 30 ft. (equivalent length of tubing/return bend)

** Wall thickness: 3/8” O.D. - .016”; 1/2 O.D. - .017”; 5/8 O.D. - .018”

1 2 ... 65 66 67 68 69 70 71 72

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Emerson Fluid Chiller Guía para resolver problemas Pagina 70

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