Bulletin 30-21 – Page 5
SERVICE
Typical Malfunctions
There are only three possible malfunctions: 1. Coil
burnout. 2. Failure to shift to Reclaim Mode. 3. Failure
to shift to Normal Mode. Each is discussed below:
COIL BURNOUT
Coil burnouts are extremely rare unless caused by one of the
following:
1. Improper electrical characteristics.
2. Continuous over-voltage, more than 10%.
3. Under-voltage of more than 15%. This applies only if the
op er at ing conditions are such that the reduced MOPD
causes stalling of the plunger, which results in excessive
current draw.
4. Incomplete magnetic circuit due to the omis sion of the
plunger assembly during reassembly.
5. Mechanical interference with movement of plunger which
may be caused by a deformed enclosing tube.
6. Coil energized while not installed on a valve.
FAILURE TO SHIFT TO RECLAIM MODE
1. Coil burnout (see coil burnout at left).
2. MOPD greater than specifications.
3. Restricted high pressure pilot connection.
4. May not have allowed sufficient time to pump out the
reclaim coil while in the normal mode.
FAILURE TO SHIFT TO NORMAL MODE
1. Stray voltage holding plunger up.
2. Restricted, closed service valve, or capped suction connec-
tion on pilot.
For a list of replacement part kits, see table on page 13.
“B” Type - PUMP DOWN or
ELECTRIC DEFROST with PUMP DOWN (unit off)
When the pump down con trol is en er gized, relay coil is en er gized.
This al lows the heat ing to control the 3-Way Heat Re claim Valve
op er a tion.
When the pump down control is de-energized, the normally closed con-
tact is closed. This by pass es the heat ing to en er gize the coil and shut
off the valve’s bleed to suction.
B
ts
ts
Reclaim
Condenser
Suction
Normal
Condenser
Discharge
Relay
Closed
Open
Line
Heating
Thermostat
(Transformer
Optional)
To Pump Down Control
ts
B
“C” Type - PUMP DOWN SYSTEM (unit off)
When the pump down control is en er gized, relay coil is en er gized.
This al lows the heat ing to control the 3-Way Heat Reclaim Valve
op er a tion.
When the pump down control is de-energized, the normally closed con-
tact is closed. This bypasses the heat ing to energize the reclaim con-
denser pump out so le noid and shut off the valve’s pump out to suc tion.
ts
ts
B
Reclaim
Condenser
Suction
Normal
Condenser
Discharge
Relay
Closed
Open
Heating
Thermostat
(Transformer
Optional)
To Pump Down Control
Line
Reclaim Condenser Pump Out
Normally
Open
ts
B
Reclaim
Condenser
Suction
Normal
Condenser
Discharge
Relay
Closed
Open
Line
Line
Defrost
Timer
Defrost
Heater
Heating
Thermostat
(Transformer
Optional)
B
ts
A
D
efrost timer en er giz es relay coil to close nor mal ly open con tact.
This bypasses the when defrosting to energize the heat re claim coil
and shut off the valve’s bleed to suction.
A B
ts
“B” Type - OFF CYCLE ELECTRIC DEFROST SYSTEM
Reclaim
Condenser
Suction
Normal
Condenser
Discharge
Relay
Closed
Open
Line
Line
Defrost
Timer
Defrost
Heater
Heating
Thermostat
(Transformer
Optional)
Reclaim Condenser
Pump Out
Normally
Open
ts
B
A
“C” Type - OFF CYCLE ELECTRIC DEFROST SYSTEM
Wiring of single compressor units may require the use of
relays to prevent high to low side bleed during periods
when the compressor is not circulating refrigerant. This is
necessary to prevent refrigerant migration to the low side of
the system where it may condense into liquid and damage
system components when the compressor restarts.
It is always a good idea to check with the equipment man-
ufacturer for recommendations on the application of heat
reclaim on the specific type of equipment. It is necessary
to adhere to local piping and electrical codes that apply to
each application. For complete product information, refer
to Bulletin 30-20.
TYPICAL WIRING SCHEMATICS & ELECTRICAL CONSIDERATIONS
Single Compressor Systems
Defrost timer en er giz es relay coil to close the nor mal ly open con-
tacts. This bypasses the when de frost ing to close the pump out solenoid
and shut off the valve’s pump out to suction.
A B
ts
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