Williamson-Thermoflo PLB-098 LOW-BOY, Instructions Manual, Page: 18 / 26

PLB-098
Oil Furnaces
– Furnace Manual
18 11/13
5. DIMENSIONS AND RATINGS (continued)
Table 12: Airflow Data, Models with 1/3 HP PSC motors
0.2" (W.C.) 0.3" (W.C.) 0.4" (W.C.) 0.5" (W.C.) 0.6" (W.C.) 0.7" (W.C.)
HIGH 1420 1335 1240 1180 1085 1025
MED-HIGH
1275 1230 1170 1095 1045 960
MED-LOW
1015 1000 955 915 860 785
LOW 815 785 775 730 690 635
BLOWER
SPEED
EXTERNAL STATIC PRESSURE WITH AIR FILTER
Table 13: Airflow Data, Models with ½ HP ECM Motors
SW1- HEAT
DIP switch position
HEAT INPUT
(USGPH)
CFM with SW3-ADJ
DIP switch position A
CFM with SW3-ADJ
DIP switch position B
CFM with SW3-ADJ
DIP switch position C
A (1=OFF, 2=OFF) 0,70 1260 1385 1135
B (1=ON, 2=OFF) 0,55 1050 1155 945
C (1=OFF, 2=ON)* 0,55 850 935 765
D (1=ON, 2=ON)*
SW2- COOL
DIP switch position
A/C size
(TON)
CFM with SW3-ADJ
DIP switch position A
CFM with SW3-ADJ
DIP switch position B
CFM with SW3-ADJ
DIP switch position C
A (1=OFF, 2=OFF) 3,0 900 990 810
B (1=ON, 2=OFF) 2,5 750 830 675
C (1=OFF, 2=ON) 2,0 600 660 540
D (1=ON, 2=ON) 1,5 450 495 405
SW2- COOL
DIP switch position
A/C size
(TON)
CFM with SW3-ADJ
DIP switch position A
CFM with SW3-ADJ
DIP switch position B
CFM with SW3-ADJ
DIP switch position C
A (1=OFF, 2=OFF) 3,0 1200 1320 1080
B (1=ON, 2=OFF) 2,5 1000 1100 900
C (1=OFF, 2=ON) 2,0 800 880 720
D (1=ON, 2=ON) 1,5 600 660 540
SW4- DELAY
DIP switch position
HEAT INPUT
(USGPH)
PreRun On-Delay
CFM Level - Time
ShortRun On-Delay
CFM Level - Time
Off-Delay
CFM Level - Time
A (1=OFF, 2=OFF) 0,7 13% - 45 sec. 19% - 30 sec 38% - 3 min.
B (1=ON, 2=OFF) 0,55 13% - 45 sec. 19% - 60 sec 38% - 3 min.
*C (1=OFF, 2=ON) 0,55 13% - 60 sec. 13% - 60 sec 38% - 3 min.
D (1=ON, 2=ON) All 13% - 30 sec. 100% - 0 sec 100% - 2 min.
No adjustment
required
A/C size
PreRun On-Delay
CFM Level - Time
ShortRun On-Delay
CFM Level - Time
Off-Delay
CFM Level - Time
- All NO DELAY NO DELAY 100% - 90 sec
NOTE: Disconnect main power to unit prior to changing DIP switch settings.
DELAY PROFILE FOR COOLING OR HEAT PUMP HEATING MODE
OIL HEATING MODE
24 VAC input (R) on W only
CONTINUOUS FAN
24 VAC input (R) on G only
COOLING OR HEAT PUMP HEATING MODE
24 VAC input (R) to G, Y/Y2 and O (for cooling)
In Cooling - Dehumidification mode, with no 24 VAC input to DH, the CFMs are reduced by 15%.
The CFMs shown are reduced by 20% if there is 24 VAC input to Y1 (first stage cooling mode)
Same value as DIP switch position A
* Alternate adjustement in oil-fired heating mode with higher temperature rise
DELAY PROFILE FOR OIL HEATING MODE
PreRun and ShortRun are the periods of time when the the blower starts at very low CFM to minimize the
distributon of cool air in the system and then runs up to normal speed.
Off Delay is the time required to cool down the heat exchanger with low CFMs, to minimize cool draft in the
air distribution system.