Carrier OBM112 Series, Installation Instructions Manual

6

Figure 6: Thermostat wiring, heating and air conditioning 

with ECM variable speed motor 

Figure 7: Thermostat wiring, heating and air 

conditioning/heat pump with ECM variable speed motor 

Note: On units with 2 stage cooling or heat pump, terminal Y1 
must be used. When Y1 on the electronic control receives a 24 
VAC signal, the air flow is reduced by 20%. Do not use 
terminal Y1 with a single stage cooling or heat pump. 

2.5 INSTALLATION

OF

THE

BURNER

Refer to the burner manufacturer’s instructions.  Also, the 
burner must be installed always in the same way 
independently of the furnace orientation. 

1.  Position the mounting gasket between the mounting 

flange and the burner mounting plate. Align the holes in 
the burner mounting plate with the studs on the mounting 
flange and bolt securely in place. 

2.  Remove the burner drawer assembly or the air tube 

assembly; 

3.  Install the nozzle (refer to Technical Specifications, 

(Table 6); 

4.  Check the electrode settings; 

5.  Make the electrical connections; 

6.  Complete oil line connections. 

2.5.1 Nozzles 

The burner comes equipped with an appropriate nozzle. 
However, if another size or a replacement nozzle is 
required, use the manufacturer’s recommended spray 
angle and type a shown in Table 1 and based on a pump 
pressure of 100 psi.  

Always select nozzle sizes by working back from the 
desired flow rate at operating pressure and not the nozzle 
marking. 

2.5.2  Air and Turbulator Settings 

Before starting the burner for the first time, adjust the air 
and turbulator settings to those listed in this manual, Table 
6. Once the burner becomes operational, final 
adjustments will be required. Refer to section 3 of this 
manual. 

2.5.3  Post purge delay adjustment 

The post purge delay on the oil-fired burners is factory set 
to zero second. This delay is applicable for all installations 
with chimney venting. For heating units installed with side 
wall venting and a burner equipped with this feature, the 
post purge delay must be set to 15 seconds. No delay is 
required for Riello burners. Refer to the burner control 
instruction manual and markings for proper adjustment of 
the post purge delay. 

2.6 VENTING 

WARNING 

Poisonous carbon monoxide gas, fire and explosion 
hazard. 

Read and follow all instructions in this section. 
Failure to properly vent this furnace can result in in 
death, bodily injury and/or property damage. 

To ensure the safe and proper functioning of an oil 
furnace, it must always be connected to a flue with 
sufficient draft or to an approved side-wall venting system. 
In addition, it is strongly recommended to perform a 
complete inspection of all the existing venting systems. 

WARNING

Poisonous carbon monoxide gas hazard. 

Never install a hand operated damper in the vent pipe. 
However, any Underwriters Laboratories listed, 
electrically operated automatic type vent damper may 
be installed if desired. Be sure to follow the 
instructions provided with vent damper. Also, read 
and follow all instructions in this section of the 
manual. 

Failure to properly vent this furnace or other 
appliances can result in death, bodily injury and/or 
property damage.