ECR International HML-C, Installation, Operation And Maintenance Manual

regulator. The flue outlet pressure (measured between 
the furnace and draft regulator, or the oil burner 
mounting plate over-fired draft access port.  fig. 2) should 
be set to -0.02 in. w.c. 

8.  OPTIONAL SIDE WALL VENTING 

Certain HML-C and HMLV-C furnace models are 
manufactured to be installed as sidewall vented units. 
Please refer to Direct Venting Instructions, P/N 
240006979 included with the Vent Kit for details. Sidewall 
Venting (

Direct Venting

) requires the use of specific oil 

burners; the Beckett AFII, or the Riello 40BF. Please 
refer to Appendix A, Tables A2, and A4. 

Note: Sidewall venting requires special attention to 
combustion air supply. There is no natural draft in the 
venting system between furnace cycles; therefore, if the 
indoor pressure is negative relative to the outdoors, the 
vent terminal becomes a point of infiltration. This could 
lead to oil odour control problems. This problem is 
rectified by the use of ducted outdoor air for combustion 
(semi-sealed combustion), using the Beckett AFII or 
Riello 40BF oil burner. See Direct Vent Instructions 
supplied with the Vent Kits.

9a.  FAN TIMER BOARD AND LIMIT CONTROL  

(FIG. 4) (page 22) 

The Electronic Fan Timer integrates control of all burner 
and circulator fan operations. This control is the central 
wiring point for most of the electrical components in the 
furnace. The 

United Technologies 1158-120 (HML-C)

has an adjustable fan on time that is set by selecting the 
dipswitch combination displayed in Chart 1. This fan on 
delay can be set at 1, 2, 4 or 6 minutes. This provides a 
delay between the burner ignition and blower start-up to 
eliminate excessive flow of cold air when the blower 
comes on. The 

United Technologies 1158-120 (HML-

C) 

has an adjustable fan off time of 30, 60, 90 or 120 

seconds displayed in Chart 1. The fan off delay time 
starts when the burner motor is de-energized at the end 
of a call for heat. Blower shutdown is delayed to remove 
any residual heat from the heat exchanger and improve 
the annual efficiency of the furnace. 

The electronic fan timer board works in conjunction with 
snap disc limit controls, which perform a safety function, 
and breaks power to the oil burner primary control, which 
shuts off the burner if the furnace over-heats. The limit 
control is thermally operated and automatically resets. 
The limit control is factory installed, pre-set and is not 
adjustable.   

If the limit control opens with the 

United Technologies 

1158-120 (HML-C) 

electronic fan control

, 

the circulating 

fan will be energized as well. When the limit closes, the 
fan off timer will begin. At the end of the fan off time cycle 
the burner will be energized, initiating a normal burner 
cycle.

CHART 1 

United Technologies 1158-120 (HML-C) 

Dip Switch Position 

Blower Delay Times 

1 2 3 4 

On 

Seconds 

Off 

Minutes 

Off Off   

30 

On Off   

60 

Off On   

90 

On On   

120 

Off 

Off   

1 

On 

Off   

2 

Off 

On   

4 

On 

On   

6 

9b.  FAN TIMER BOARD AND LIMIT 

CONTROL (FIG. 5) (page 22) 

The 

United Technologies 1168-1 ECM (HMLV-C) 

tap board has an adjustable fan on/off delay that 
must be adjusted in accordance with the furnace 
input rating (nozzle size).  Refer to Table A-10 (pg 
15) for ECM blower set-up.

10.  ELECTRICAL CONNECTIONS 

The furnace is listed by the Canadian Standards 
Association under the NRTL (North American) 
Standard. It is factory wired and requires minimal 
field wiring. All field wiring should conform to 
CAN/CSA C22.1 Canadian Electrical Code, Part 1, 
and by local codes, where they prevail. In the United 
States, the wiring must be in accordance with the 
National Fire Protection Association NFPA-70, 
National Electrical Code, and with local codes and 
regulations. 

The furnace should be wired to a separate and 
dedicated circuit in the main electrical panel; 
however, accessory equipment such as electronic 
air cleaners and humidifiers may be included on the 
furnace circuit. Although a suitably located circuit 
breaker can be used as a service switch, a separate 
service switch is advisable. The service switch is 
necessary if reaching the circuit breaker involves 
becoming close to the furnace, or if the furnace is 
located between the circuit breaker and the means 
of entry to the furnace room. The furnace switch 
(service switch) should be clearly marked, installed 
in an easily accessible area between the furnace 
and furnace room entry, and be located in such a 
manner to reduce the likelihood that it would be 
mistaken as a light switch or similar device. 

The power requirement for the HML-C and HMLV-C 
models is: 120 VAC, 1 Ø, 60 Hz., 12A. 

Accessories requiring 120 VAC power sources such 
as electronic air cleaners and humidifier 

30173 Rev B 4/29/2008 

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