Olsen HTL-90D, Installation, Operation & Maintenance Manual

6

cONTROls  &  cONNecTIONs

barometric Damper control

The barometric damper control, also known as a draft regulator, 

is used on conventional chimney venting only. This control auto-

matically maintains a constant negative pressure in the furnace to 

obtain maximum efficiency. It ensures that proper pressures are 

not exceeded. If the chimney does not develop sufficient draft, the 

draft control cannot function properly. The draft regulator, when 

installed should be in the same room or enclosure as the furnace and 

should not interfere with the combustion air supplied to the burner. 

The control should also be located near the furnace flue outlet and 

installed according to the instructions supplied with the regulator. 

The flue outlet pressure (measured between the furnace and draft 

regulator, or the oil burner mounting plate over-fired draft access 

port ,

Figure 2

) should be set to -0.02 in. w.c.

fan Timer board and limit control  (fIg. 4) (page 21)

The Electronic Fan Timer integrates control of all burner and circu-

lator fan operations. This control is the central wiring point for most 

of the electrical components in the furnace. The United Technolo-

gies 1158-120 (HTL-D) has an adjustable fan on time that is set by 

selecting the dipswitch combination displayed in 

Table 2

. This 

fan on delay can be set at 30, 60 90 or 120 seconds. 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 (HTL-D) has an adjustable fan off time of 1, 

2, 4 or 6 minutes displayed in 

Table 2

. 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 

(HTL-D) 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. 

fan Timer board and limit control (fig. 5) (Page 21)

The United Technologies 1168-1 ECM (HTLV-D) tap board has an 

adjustable fan on/off delay that must be adjusted in accordance with 

the furnace input rating (nozzle size).  

Refer to Tables 8A and 8B 

(pg 16 and 17)

 for ECM blower set-up.

Table 2 - united Technologies 1158-120 (hTl-D)

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

electrical connections

The furnace is listed by the Canadian Standards Association un-

der 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 fur-

nace 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 eas-

ily 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 HTL-D and HTLV-D models is: 120 

VAC, 1 Ø, 60 Hz., 12A.
Accessories requiring 120 VAC power sources such as electronic 

air cleaners and humidifier transformers may be powered from the 

electronic fan timer board where provisions have been made for con-

nections, but should have their own controls. Do not use the direct 

drive motor connections as a power source, since there is a high risk 

of damaging the accessories by exposure to high voltage from the 

auto-generating windings of the direct drive motor.
Thermostat wiring connections and air conditioning contactor low 

voltage connections are shown in the wiring diagrams on page 18 of 

this manual. Some micro-electronic thermostats require additional 

controls and wiring. Refer to the thermostat manufacturer's instruc-

tions.