Start-Up; Leak Test; Evacuate And Dehydrate; Charge System - Bryant 619B Installation, Start-Up And Service Instructions Manual

H. Reconfigure for One Fan Coil Unit per Compressor
Circuit if Necessary
The control also provides the option of using either 1 or 2 fan
coil units per compressor (depending on the position of the
jumpers on J3 and J4 on the control board). See Fig. 12. The
control is preset to 2 fan coil units per compressor at the fac-
tory. If only one fan coil per compressor is to be used, position
a jumper between pins 1 and 2 on J3 and J4 (one jumper for
each set of pins). Jumper J3 is associated with the compres-
sor on the 538S _ 024 units and compressor number 1 on
538S _ 048 units (bottom compressor). Jumper J4 is associ-
ated with compressor number 2 on the 538S _ 048 units.

START-UP

I. LEAK TEST
Field piping and all tubing connections must be leak tested
by the pressure method. Use R-22 at approximately 25 psig
backed up with an inert gas to reach a total system pressure
not to exceed 245 psig.
II. EVACUATE AND DEHYDRATE
Field piping and fan coil must be evacuated and dehydrated
to 1,000 microns using accepted practices.
WARNING: Service valves must be fully backseated
to close service port. There is no Schrader valve at the
service port, and failure to backseat the valve could re-
sult in loss of system charge or personal injury.
III. CHARGE SYSTEM
Release charge into system by opening (backseating) vapor
supply and vapor return line service valves. Open ONLY those
service valve sets which have fan coil unit sections connected
to them. DO NOT open valves where no field tubing has been
connected.
IV. PRELIMINARY CHECKS
Complete Start-Up Checklist on page CL-1 and the following
checks prior to starting up unit.
1. Check condensate drainage system. To do this, add a small
amount of water into each fan coil unit condensate pan,
and ensure that each pan drains freely. Inspect drain
pans and lines, and clean as required.
2. Make sure that all wiring connections are correct and
tight.
3. Check all barriers, covers, and panels to ensure they are
in place.
4. Identify which fan coil unit valve sets have been
connected.
IMPORTANT: DO NOT open valves which do not have
fan coil units connected to them.
5. Unit is shipped with the valve stems frontseated and
caps factory installed. Remove caps from all valves to
which fan coil units have been connected. Replace caps
and tighten until finger tight.
6. Fully backseat (open) the vapor supply and vapor re-
turn tube service valves.
7. Turn on main disconnect switch(es) to indoor fan coil units
and outdoor condensing unit.
8. Using the remote controller for each indoor fan coil unit,
turn on each fan coil unit and operate each unit in each
mode (i.e., electric heat [if provided], and fan cooling)
for 15 minutes to test for proper operation.
9. Test for proper refrigerant charge in each circuit using
the subcooling method.
V. OPERATING SEQUENCE
NOTE: AUTO. fan mode is used as the unit operation ex-
ample for ALL fan coil units in this section. Contact your lo-
cal Carrier dealer for operation information in other fan modes.
A. Fan Coil Units
Each fan coil unit has a self-contained control system that
determines the set point for fan coil operation, fan mode op-
eration, and heating mode operation (if provided). The 619B
and 619C fan coil units are equipped with either a wired or
wireless remote controller set (remote controller is not avail-
able for 619F fan coil units). Set points and fan modes may
be determined separately for each fan coil unit.
Each fan coil unit may call for cooling operation indepen-
dently. On a call for cooling operation by a single fan coil unit,
a 24-v signal is sent to the 538S outdoor unit and energizes a
control relay. The indoor blower starts according to the nor-
mal fan coil unit sequence of operation. The control relay (in
the outdoor unit) initiates operation of a cooling cycle for the
respective indoor unit refrigerant circuit; including opening
a liquid line solenoid valve in the outdoor unit.
As the set point at each fan coil is satisfied, its individual
24-v signal to the 538S unit stops, and the respective sole-
noid valve for each fan coil unit closes. The indoor fan cycles
off. The 619B and 619C fan coil units then begin room sam-
pling operation after a 3-minute off period (during sampling,
the fan motor runs at low speed for 1 minute to sample the
demand in the space; then cycles off until the next sampling
period if no demand is found).
B. 538S Outdoor Condensing Unit
The outdoor unit is equipped with a control that will monitor
the indoor fan coil unit cooling request. The control will turn
on solenoid valves for the appropriate indoor fan coil unit sys-
tem. The control will also combine the cooling requests to con-
trol up to 2 compressors.
The control provides a 2-minute compressor time-delay de-
vice which disables the compressor for 2 minutes. The time
delay device timers will be initialized when the unit is pow-
ered up (for the first 2 minutes).
The 538S unit control includes an integral head pressure con-
trol function. This function will maintain a minimum head
pressure by cycling the outdoor fan motor in response to in-
puts from the thermistor (for outdoor ambient temperature)
and the transducers (for system discharge pressures in each
compressor circuit).
The head pressure for the compressor(s) will be monitored to
control the outdoor fan output. The control reads an outdoor
temperature thermistor to determine if the head pressure should
be used to control the outdoor fan output.
Operation
The 538S unit receives a 24-v control signal from each fan
coil unit as each fan coil unit initiates a demand for cooling.
The 24-v signal energizes a control relay in the 538S unit (one
relay per fan coil unit). The refrigerant flow to each fan coil
unit is controlled through a solenoid valve (one valve per fan
coil unit). The solenoid valve(s) will not open until compres-
sor operation is initiated by the controller.
The microprocessor control in the 538S unit includes a 2-minute,
anti-short cycle, time-delay function. This function provides
a minimum time-off delay between compressor run stages
(2 minutes each from the end of the last on period to the be-
ginning of the next on period). If more than 2 minutes have
passed since the end of the last on period, the compressor
will be ready to restart with initiation of demand from any
fan coil unit on its circuit.
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