Reznor OH Unit Installation Manual - Manual (Page 16)

Form I-OH, PN 120390 R5, Page 16
FIGURE 17 -
Burner Pump
Vacuum Check - A vacuum gauge may be installed on either side of the 1/4"
inlet ports or in the 1/8" return port (on single pipe installation), whichever is
most convenient. With a standard 1-stage pump, vacuum should not exceed
6" hg on single-pipe system or 12" hg on two-pipe system. With an optional 2-
stage pump, vacuum should not exceed 17" hg.
IMPORTANT: Long or oversized inlet lines may require the pump to operate during
initial bleeding period. In such cases, the priming may be assisted by injecting fuel oil
into the pump gearset. Under lift conditions, oil lines and fittings must be airtight. To
assure this, oil resistant pipe dope should be applied to both the used and unused inlet
and both return fittings.
Fan and Limit Controls
This heater is equipped with a fan and limit control assembly consisting of a specially
designed control mounting bracket with a fan control, a circulating air high limit control,
and a super high limit control attached. To access the fan and limit control assembly,
remove the plate illustrated in FIGURE 18. For service information, see Troubleshoot-
ing Guide, High Limit Cycles, Paragraph 9.3.
The main functions of the fan/blower control are to provide (1) delay of fan or blower
operation, preventing circulation of cold air at startup, and (2) continued fan or blower
operation as long as the unit temperature is above the minimum setting (120°F). The
fan/blower control also provides additional safety control by keeping the fan or blower
in operation in the event that a malfunction would cause the oil burner to continue to
fire when the thermostat is satisfied.
Remove plate to access fan
and limit control assembly.
Circulating Air
High Limit
Fan
Control
FIGURE 18 - Access
and Identification of
the Fan and Limit
Controls
Fan and Limit
Control Assembly
Super
Limit
7. Electrical
Supply and
Connections
(cont'd)
7.4 Major
Components
(cont'd)
CAUTION: Pres-
surized or gravity
feed installations
must not exceed 3
PSI on inlet line or
return line at the
pump. A pressure
greater than 3 PSI
may cause damage
to the shaft seal.