Touch Test Chart : To Service Reversing Valves - Friedrich ZoneAire Premier R-32 Series Service Manual

Touch Test Chart : To Service Reversing Valves

VALVE
OPERATING
CONDITION
Normal Cooling
Normal Heating
Valve will not
shift from cool
to heat.
Valve will not
shift from cool
to heat.
Starts to shift
but does not
complete
reversal.
Apparent
leap in heat-
ing.
Will not shift
from heat to
cool.
14
36
COMPONENT TESTING
NORMAL FUNCTION OF VALVE
1 2 3 4
Cool Hot
Hot Cool *TVB
as (2) as (1)
Hot Cool
Hot Cool *TVB
as (1) as (2)
MALFUNCTION OF VALVE
Check Electrical circuit and coil
Check refrigeration charge
Cool, Hot,
Hot Cool *TVB
as (2) as (1)
Cool, Hot,
Hot Cool *TVB
as (2) as (1)
Cool, Hot,
Hot Cool
as (2) as (1)
Cool, Hot,
Warm Cool *TVB
as (2) as (1)
Hot Warm Warm Hot
Hot Warm Warm Hot
Hot Hot Hot Hot
Hot Hot Hot Hot
Hot, Cool,
Hot Cool *TVB
as (1) as (2)
Hot, Cool,
Hot Cool **WVB
as (1) as (2)
Hot, Cool,
Hot Cool *TVB
as (1) as (2)
Hot, Cool,
Hot Cool
as (1) as (2)
Hot, Cool,
Hot Cool
as (1) as (2)
Hot, Cool,
Hot Cool
as (1) as (2)
Warm, Cool,
Warm Cool
Warm
as (1) as (2)
Figure 704 (Touch Test Chart)
* TEMPERATURE OF VALVE BODY
** WARMER THAN VALVE BODY
5 6 POSSIBLE CAUSES
TVB
TVB
No voltage to coil.
Defective coil.
Low charge.
Pressure differential too high.
Hot Pilot valve okay. Dirt in one bleeder hole.
Piston cup leak
*TVB Clogged pilot tubes.
Both ports of pilot open. (Back seat port
Hot Hot
did not close).
Warm Defective Compressor.
Not enough pressure differential at start
*TVB Hot of stroke or not enough fl ow to maintain
pressure differential.
Body damage.
Hot Hot Both ports of pilot open.
*TVB Hot Body damage.
Valve hung up at mid-stroke. Pumping
volume of compressor not suffi cient to
maintain reversal.
Hot Hot Both ports of pilot open.
*TVB Piston needle on end of slide leaking.
**WVB Pilot needle and piston needle leaking.
*TVB Pressure differential too high.
Clogged pilot tube.
Hot *TVB Dirt in bleeder hole.
Hot *TVB Piston cup leak.
Hot Hot Defective pilot.
*TVB
Defective compressor.
NOTES:
CORRECTIONS
Repair electrical circuit.
Replace coil.
Repair leak, recharge system.
Recheck system.
Deenergize solenoid, raise head pressure,
reenergize solenoid to break dirt loose.
If unsuccessful, remove valve, wash
out. Check on air before installing. If no
movement, replace valve, add strainer to
discharge tube, mount valve horizontally.
Stop unit. After pressures equalize, restart
with solenoid energized. If valve shifts,
reattempt with compressor running. If still
no shift, replace valve.
Raise head pressure, operate solenoid to
free. If still no shift, replace valve.
Raise head pressure, operate solenoid
to free
partially clogged port. If still no shift,
replace
valve.
Replace compressor
Check unit for correct operating pressures
and charge. Raise head pressure. If no
shift, use valve with smaller port.
Replace valve
Raise head pressure, operate solenoid. If
no shift, use valve with smaller ports.
Replace valve
Raise head pressure, operate solenoid. If
no shift, use valve with smaller ports.
Raise head pressure, operate solenoid.
If no
shift, replace valve.
Operate valve several times, then recheck.
If excessive leak, replace valve.
Operate valve several times, then recheck.
If excessive leak, replace valve.
Stop unit. Will reverse during equalization
period. Recheck system
Raise head pressure, operate solenoid to
free dirt. If still no shift, replace valve.
Raise head pressure, operate solenoid.
Remove valve and wash out. Check on air
before reinstalling, if no movement, replace
valve. Add strainer to discharge tube.
Mount valve horizontally.
Stop unit. After pressures equalize, restart
with solenoid deenergized. If valve shifts,
reattempt with compressor running. If it
still will not reverse while running, replace
the valve.
Replace valve.
Replace compressor