Tjernlund HS3,4,5 Series with UC1 Universal Control (Version X.02) 8504111 Rev 09/02 - Manual (Page 14)

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DRAFT ADJUSTMENT AND COMBUSTION AIR
The Power Venter Fan Proving Switch is designed to disable the appliance gas valve or burner motor upon Power Venter failure only!
It is not designed and cannot replace, regular vent system inspection, appliance servicing and combustion testing.
1. Close all doors and windows of the building. If the appliance is installed in a
utility room or closet, close the entrance door to this room.
2. Turn on all exhaust and ventilation fans to maximum speeds. Do not operate a
fan used strictly for Summer exhausting.
3. Following the appliance manufacturer’s instructions, place the appliance in
operation, set thermostat for continuous operation.
4. Verify that Power Venter operates first, prior to burner ignition. Watch to make
sure burner lights off properly.
GAS
After allowing appliance(s) to operate for 15 minutes, follow the appliance manufacturers instructions to verify that the recommended
draft is present. In general, most gas appliances will operate safely with flue outlet draft levels from -0.02 to -0.05" W.C.. If the draft
is excessive, make necessary adjustments to the barometric control and/or follow the, “Power Venter Air Flow Damper Adjustment”
procedure outlined below. As a cross check, a candle or match can be held adjacent to the draft hood or barometric control to verify
flame/smoke is being drawn into, and not rolling out of edge of the relief opening, (See Diagram A). If exhaust gases are escaping
from the relief opening of the draft hood or barometric control, the equipment should not be operated until proper adjustments or
repairs are made to provide adequate draft levels.
5. Next, turn on all other fuel-burning appliances within the same room so they will operate at their full input. Repeat Step 3 above,
checking the draft on each appliance.
POWER VENTER AIR FLOW DAMPER ADJUSTMENT
The Air Flow Damper Adjustment on the Power Venter is factory set for maximum air flow. Operating a properly sized Power Venter at
its maximum setting will assure that combustion gases are safely removed to the outside. If the Power Venter has excess venting
capacity than what is required for this application, operating the Power Venter with the air-flow adjustment at the maximum setting
may draw more dilution air than necessary.
The Air Flow Damper Adjustment may be set by use of a combustion analyz-
er, inclined manometer or draft gauge. Alternatively, the damper adjustment
can be set using a smoke candle or taper, as follows:
1. With all exhaust fans operating, air inlets closed and all appliances firing
(as instructed above), hold a lighted match or taper around the edge of the
relief opening of the draft hood(s) or barometric draft control, (See Diagram A).
2. Set Air Flow Adjustment by loosening locknut and turning damper rod
handle. CAUTION: HANDLE MAY BE HOT, use pliers to move handle.
Position of rod handle indicates the position of Air Flow Adjustment inside
housing, ( See Diagram B).
3. Using pliers, move handle towards minimum draft setting until spillage is
detected at draft hood relief opening, then re-open Air Flow Adjustment just
enough to eliminate spillage.
4. Lock Air Flow Adjustment at desired setting by tightening locknut.
5. Return doors, windows, exhaust fans, fireplace dampers and appliances to their previous conditions of use.
COMBUSTION AIR
Adequate combustion air is vital for proper combustion and for safe venting. Likewise, for proper Power Venter performance, ade-
quate combustion air must be available to the appliance. Many installers assume adequate combustion air is present, especially in
older buildings. In some cases this is a false assumption, because many older buildings have been made "tight" due to weatheriza-
tion. Size the combustion air opening(s) into the appliance room as outlined local or national codes. Tjernlund’s IN-FORCER
TM
Combustion Air Intake Systems provide a convenient interlocked way to provide combustion air to the equipment room. When
installing a Power Venter it is not necessary to supply any more combustion air than normally required when conventional venting.
Common symptoms of inadequate combustion air include: Fan Proving Switch short cycling, odor present at end of burner cycle, out-
side air enters the structure through the Power Venter during appliance off cycle.
PROPER
DRAFT
ESTABLISHED
PROPER
DRAFT
ESTABLISHED
DIAGRAM A
DIAGRAM B