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

8

!

CAUTION

ALL FURNACE CONTROLS ARE SENSITIVE AND 

SHOULD NOT BE SUBJECTED TO TAMPERING. IF 

PROBLEMS PERSIST, CALL YOUR SERVICE CON-

TRACTOR.

combustion chamber

This furnace is equipped with a high quality cerafelt combustion 

chamber. It is held in place by a retaining bracket.

NOTICE

Check the alignment of the combustion chamber and 

oil burner before firing. It is possible for the combustion 

chamber to shift if subjected to rough handling during 

transit. 

!

CAUTION

DO NOT CONNECT POWER LEADS BETWEEN MO-

TOR SPEEDS. THE NEUTRAL WIRE MUST ALWAYS 

BE CONNECTED TO THE MOTOR'S DESIGNATED 

NEUTRAL TERMINAL.

If the joining of the blower speed wiring is done in the furnace junc-

tion box, tape off both ends of the unused wire.
Do not use the blower speed wires as a source of power to acces-

sories as electronic air cleaners and humidifier transformers.  The 

unused motor taps auto-generate sufficiently high voltages to dam-

age accessory equipment.

!

WARNING

DISCONNECT THE POWER SUPPLY TO THE FUR-

NACE BEFORE OPENING THE BLOWER ACCESS 

DOOR TO SERVICE THE AIR FILTER, FAN AND 

MOTOR. FAILURE TO SHUT OFF POWER COULD 

ALLOW THE BLOWER TO START UNEXPECTEDLY, 

CREATING A RISK OF DEATH OR PERSONAL INJURY.

circulating Air blower (hTlV-D) - (see Page 10, ecM 

blOWeR MOTOR OPeRATION (hTlV-D))

cOMbusTION chAMbeR

circulating Air blower (hTl-D)

The HTL-D and HTLV-D furnace models are equipped with direct 

drive blower systems.  HTL-D models are equipped with PSC mo-

tors; HTLV-D models are equipped with electronically commutated 

motors (ECM).  Direct drive blower speed adjustments are not 

normally required in properly sized extended plenum duct systems. 

The motor RPM and air CFM delivery will vary automatically (on 

ECM motor equipped models) to accommodate conditions within 

the usual range of external static pressures typical of residential duct 

systems. Under-sized duct systems may require a higher blower 

speed to obtain a reasonable system temperature rise. Some older 

duct systems were not designed to provide static pressure. They 

typically feature special reducing fittings at each branch run and lack 

block ends on the trunk ducts. These systems may require modifica-

tion to provide some resistance to the airflow to prevent over amping 

of the direct drive blower motor. Selecting a lower blower speed may 

correct this problem. Direct drive blower speeds are adjusted by 

changing the "hot" wires to the motor winding connections. Please 

refer to wiring diagrams on page 18 of this manual or the wiring dia-

gram label affixed to the furnace. THE NEUTRAL WIRE (normally 

the white wire) IS NEVER MOVED TO ADJUST THE BLOWER 

SPEED.
It is possible and acceptable to use a single blower speed for both 

heating and cooling modes. The simplest method to connect the 

wiring from both modes is to use a "piggy-back connector" accom-

modating both wires on a single motor tap. It is also acceptable to 

connect the selected motor speed with a pigtail joined to both heat-

ing and cooling speed wires with a wire nut. As a safety precaution 

against accidental disconnection of the wires by vibration, it is advis-

able to secure the wire nut and wires with a few wraps of electricians 

tape.

The combustion chamber should be inspected for damage or carbon 

build up whenever the oil burner is removed for repairs or routine 

maintenance.

!

CAUTION

DO NOT START THE BURNER UNLESS THE BLOWER 

ACCESS DOOR IS SECURED IN PLACE.

cIRculATINg AIR blOWeR