FloAire Indirect Fired Heater - Manual (Page 16)

16
Maxitrol Amplifier
Pulley Combination Chart
Motor RPM 1725
1/3 to 1-1/2 HP MOTOR PULLEY Dd1 Dd2 Pd1 Pd2
AX BELTS 1VL34 1.9 2.9 2 3
Open Closed
BLOWER PULLEY DATUM DIAMETER PITCH DIAMETER 5 4 1/2 4 3 1/2 3 2 1/2 2 1 1/2 1 1/2 0
AK114 11 11.2 308 323 339 354 370 385 400 416 431 447 462
1/3 to 2 HP MOTOR PULLEY Dd1 Dd2 Pd1 Pd2
AX BELTS 1VL40 2.4 3.4 2.6 3.6
Open Closed
BLOWER PULLEY DATUM DIAMETER PITCH DIAMETER 5 4 1/2 4 3 1/2 3 2 1/2 2 1 1/2 1 1/2 0
AK114 11 11.2 400 416 431 447 462 477 493 508 524 539 554
AK94 9 9.2 488 506 525 544 563 581 600 619 638 656 675
AK79 7.5 7.7 582 605 627 650 672 694 717 739 762 784 806
AK66 6.2 6.4 701 728 755 782 809 836 863 889 916 943 970
AK54 5 5.2 863 896 929 962 995 1028 1062 1095 1128 1161 1194
AK46 4.2 4.4 1019 1059 1098 1137 1176 1215 1255 1294 1333 1372 1411
AK39 3.5 3.7 1212 1259 1305 1352 1399 1445 1492 1539 1585 1632 1678
AK32 3 3.2 1402 1455 1509 1563 1617 1671 1725 1779 1833 1887 1941
3 to 5 HP MOTOR PULLEY Dd1 Dd2 Pd1 Pd2
BX BELTS 2VP42 2.9 3.9 3 4
Open Closed
BLOWER PULLEY DATUM DIAMETER PITCH DIAMETER 6 5 1/2 5 4 1/2 4 3 1/2 3 2 1/2 2 1 1/2 1 1/2 0
2BK160H 15.4 15.7 330 339 348 357 366 375 385 394 403 412 421 430 439
2BK140H 13.4 13.7 378 388 399 409 420 430 441 451 462 472 483 493 504
2BK120H 11.4 11.7 442 455 467 479 491 504 516 528 541 553 565 577 590
2BK110H 10.4 10.7 484 497 511 524 537 551 564 578 591 605 618 631 645
2BK100H 9.4 9.7 534 548 563 578 593 608 622 637 652 667 682 697 711
2BK90H 8.4 8.7 595 611 628 644 661 677 694 710 727 744 760 777 793
2BK80H 7.4 7.7 672 691 709 728 747 765 784 803 821 840 859 877 896
2BK70H 6.4 6.7 772 794 815 837 858 880 901 923 944 965 987 1008 1030
2BK60H 5.4 5.7 908 933 958 984 1009 1034 1059 1084 1110 1135 1160 1185 1211
2BK55H 4.9 5.2 995 1023 1050 1078 1106 1133 1161 1189 1216 1244 1272 1299 1327
2BK50H 4.4 4.7 1101 1132 1162 1193 1223 1254 1285 1315 1346 1376 1407 1438 1468
7-1/2 to 10 HP MOTOR PULLEY Dd1 Dd2 Pd1 Pd2
BX BELTS 2VP60 4.3 5.5 4.7 5.9
Open Closed
BLOWER PULLEY DATUM DIAMETER PITCH DIAMETER 6 5 1/2 5 4 1/2 4 3 1/2 3 2 1/2 2 1 1/2 1 1/2 0
2BK160H 15.4 15.7 516 527 538 549 560 571 582 593 604 615 626 637 648
2BK140H 13.4 13.7 592 604 617 630 642 655 667 680 693 705 718 730 743
2BK120H 11.4 11.7 693 708 722 737 752 767 781 796 811 826 840 855 870
2BK110H 10.4 10.7 758 774 790 806 822 838 854 871 887 903 919 935 951
2BK100H 9.4 9.7 836 854 871 889 907 925 943 960 978 996 1014 1031 1049
2BK90H 8.4 8.7 932 952 972 991 1011 1031 1051 1071 1091 1110 1130 1150 1170
2BK80H 7.4 7.7 1053 1075 1098 1120 1143 1165 1187 1210 1232 1255 1277 1299 1322
TURNS ON MOTOR PULLEY
TURNS ON MOTOR PULLEY
1
0
-
1
8
I
N
.
B
L
O
W
E
R
TURNS ON MOTOR PULLEY
TURNS ON MOTOR PULLEY
Sequence of Operation
The Indirect-fired heater is most easily understood when broken down into smaller individual systems.
There are two main systems, a make-up air fan and a heater. The make-up air fan consists of a heavy-
duty blower and motor. The heater may be further broken down into two control systems, the Flame
Safety Control (FSC) and the Modulating Gas System (MGS). The burner mixes air with the gas (Natural
or Propane) which heats a heat exchanger which heats the air.
Modulating Gas System
The first system, the Maxitrol modulating gas system, consists of a
temperature selector dial, a discharge air sensor, an amplifier, and a modulating
gas valve. The two types of Maxitrol systems found on these units are the
Maxitrol 20/30 and the Maxitrol 21/31. The 20 and 21 series are for single
furnace arrangement and the 30 and 31 series are for multiple furnace
arrangement. The Maxitrol 21/31 utilizes a discharge air sensor and modulates
the discharge air to the selected temperature on the temperature selector dial.
The Maxitrol 20/30 utilizes a room temperature sensor/selector in order to
control the room temperature. The modulating gas valve controls the amount of gas to the burner based
on the temperature rise needed. When the modulating gas valve is all the way open and achieving the
maximum BTUs and temperature rise of the unit, it is called “high fire”.