Reznor JT4BD Unit Installation Manual - Manual (Page 10)

10
system operation. Refer to Figures 6-12 (pages 14-
17) and Tables 3-9 (pages 12 - 14) for correct system
charging.
• The refrigerant charge can be checked and adjusted
through the service ports provided external to the
outdoor unit. Use only gage line sets which have a
“Schrader” depression device present to actuate the
valve. A common suction port for heating mode charging
is included and located on the compressor access panel
above the outdoor unit service valves.
• Heat Mode Verification Tables (Tables 10 - 16, pages
19 - 21) are provided for quick reference when the unit
is in heating mode and for the inspection of the liquid
line pressures and temperatures.
Charging the Unit in AC Mode with Outdoor
Temperatures Above 55° F
(for optimized sub-cooling of 10° F to 12° F)
1. With the system operating at steady-state, measure the
liquid refrigerant pressure (in psig) at the outdoor unit
service valve.
2. Measure the liquid refrigerant temperature (in
Fahrenheit) at the service valve.
3. Determine the required liquid refrigerant pressure. Refer
to Figures 6-12 (pages 14-17) & Tables 3-9 (pages 12-
14).
• If the pressure measured in Step 1 is greater than
the required liquid refrigerant pressure determined in
Step 3, then there is too much charge in the system.
Remove refrigerant and repeat Steps 1 through 3
until the system is correctly charged.
• If the pressure measured in Step 1 is less than the
required liquid refrigerant pressure determined in
Step 3, there is too little charge in the system. Add
refrigerant and repeat Steps 1 through 3 until the
system is correctly charged.
The 5 minute time delay feature can be shortened 1 time
to 1 second by jumping the test to c terminal. Remove
the jumper and repeat as desired.
notE: If jumper is left on the test to common pins
permanently, the defrost cycle will become inoperable.
Defrost Test Procedure
1. Jumper
t2 to DFt at the test terminals.
2. With unit running in heat mode, short the tESt terminal
to the common terminal near it. This will speed up the
board and cause it to enter defrost mode in 5/10/15
seconds depending on the defrost time selection.
Compressor delay will not function during speed-up.
3. This test will end in 5 seconds if the tESt-common
short is not removed.
4. Remove both the short and the t2 to DFt jumper to
terminate the defrost cycle. The 30 second compressor
delay should operate normally.
5. Test is complete, reset thermostat to home owner
preference.
anti Short cycle timer test
The 5 minute time delay feature can be bypassed or
shortened to 1 second by jumping the test to c terminal.
notE: If jumper is left on the test to common pins
permanently, the defrost cycle will become inoperable.
refrigerant charging
WarnIng:
t4BD Split System Heat Pumps are shipped
charged with r410a refrigerant and ready
for installation. If repairs make it necessary
for evacuation and charging, it should only
be attempted by qualified trained personnel
thoroughly familiar with this equipment. under
no circumstances should the owner attempt to
install and/or service this equipment. Failure to
comply with this warning could result in property
damage, personal injury, or death.
After refrigerant line connections are completed, it is
required that you leak check and evacuate the indoor
section and all line connections (using proper methods)
before finalizing the full system refrigerant charge.
• To achieve rated capacity and efficiency, the compressor
must be exposed to refrigerant for at least 24 hours
prior to running and then the compressor must be run
for a minimum of 12 hours.
• Cooling mode charging charts are applicable only to
matched assemblies of NORDYNE equipment and listed
airflows for the indoor coil. T4BD outdoor units with
non-AHRI lsited indoor coils are not recommended and
deviations from rated airflows or non-listed combinations
may require modification to the expansion device and
refrigerant charging procedures for proper and efficient
HEat PuMP MaIntEnancE
WarnIng:
to prevent electrical shock, personal injury, or
death, disconnect all electrical power to the unit
before performing any maintenance or service.
the unit may have more than one electrical
supply.
Proper maintenance is important to achieve optimum
performance from the heat pump. The ability to properly
perform maintenance on this equipment requires certain
mechanical skills and tools. If you do not possess these
skills, contact your dealer for maintenance. Consult your
local dealer about the availability of maintenance contracts.
Routine maintenance should include the following:
• Inspect and clean or replace air filters at the beginning
of each heating and cooling season, or more frequently
if required.