Reznor RPB Unit Installation Manual - Manual (Page 28)

Form I-RPB, P/N 131782 R11, Page 28
1. A fan control provides for the following control of the blower.
(a) After the gas valve opens, there is a time delay of blower operation to prevent
the discharge of cold air.
(b) Blower operation continues after the thermostat is satisfied as determined by
the fan time delay.
2. To be sure that the blower can continue to operate, the power supply to the
furnace MUST NOT be interrupted except when servicing the unit.
3. If the customer wants the furnace off at night, the gas valve circuit SHOULD
BE OPENED by a single pole switch wired in series with the thermostat. Some
thermostats are provided with this feature. Multiple units controlled from a single
thermostat are shut off in the same manner. For proper operation, be sure the fan
control wiring is observed. For location, see FIGURE 29, Item 12.
7.5.1 Fan Control
Service NOTE: To replace
the fan control on units
manufactured prior to
11/04, a replacement kit is
required. Order P/N 209184.
7.5.2 Reverse Flow
Limit Control
These outdoor furnaces are factory equipped with an automatic reset reverse flow
limit control. This control is located in the blower compartment, mounted in the blower
junction box adjacent to the blower inlet opening, and is wired in series with the main
limit control mounted on the heat exchanger duct side. For location, see FIGURE 29,
Item 32.
In case of belt breakage or motor failure, the limit control will be opened by the high
temperatures caused by reverse flow from the heat exchanger to the blower com-
partment, thus breaking the circuit to the automatic electric gas valve and preventing
burner operation.
7.0 Electrical Supply and Connections (cont'd)
27 30 31 32 33 34 35 36 37 38 39 40
26 29 25 28 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7
Optional
Downturn
Plenum
(Option AQ)
41 1 2 3 4 5 6
FIGURE 29 - Location of Standard and Optional Controls
1. Opt Auto Reset Discharge
Temperature Low Limit
2. Combustion Air Pressure
Switch
3. Opt Discharge Air Firestat
4. Ignition Controller
5. Optional Maxitrol Discharge
Air Sensor (Opt AG8 or 9)
6. Optional Two-Stage Controller
(Opt AG3) or Maxitrol Amplifier
(Opt AG7, 8, or 9)
7. Optional Main Low Gas Pres-
sure Switch
8. Optional Pilot High Gas Pres-
sure Switch
9. Optional Main High Gas Pres-
sure Switch
10. Time Delay Relay
11. Limit Control
12. Fan Control
13. Optional Discharge Tem-
perature Low Limit Time Delay
Relay
14. Line Voltage Terminal Block
15. Low Voltage Terminal Block
16. Discharge Temperature Low
Limit Relay
17. Optional Dirty Filter Pressure
Switch
18. Line Voltage Connection (field)
19. Optional Convenience Outlet
20. Blower Motor Contactor or
Starter
21. Optional High Ambient Limit
Control
22. Optional Outside Air or Return
Air Controller
23. Optional Mixed Air Controller
24. Optional Potentiometer
25. Optional Return Air Dampers
26. Optional Two Position or
Modulating Damper Motor
27. Optional Outside Air Damper
28. Optional Potentiometer
29. Optional Filters
30. Blower Motor
31. Optional Control Relays (as
required, 8 maximum)
32. Auto Reset Reverse Flow Limit
33. Optional Return Air Firestat
34. Low Voltage Terminal Strip
35. Line Voltage Terminal Strip
36. Control Transformer
37. Control Transformer (as
required)
38. Optional Damper Motor
Transformer
39. Low Voltage Connection (field)
40. Optional Air Proving switch
41. Venter Assembly
7.5 Electrical Operating Components