FIGURE 21 - UPFLOW AND
DOWNFLOW
11.4.2 PRIMING CONDENSATE TRAP
IMPORTANT:
THE CONDENSATE DRAIN TRAP ASSEMBLY SHOULD BE FULL OF WATER (PRIMED)
BEFORE STARTING THE FURNACE. TO FILL THE CONDENSATE DRAIN TRAP ASSEMBLY,
TEMPORARILY REMOVE THE VENT DRAIN HOSE FROM THE EXHAUSTER ASSEMBLY
ELBOW/DRAIN FITTING, AND POUR APPROXIMATELY ONE CUP OF WATER DOWN THE
HOSE. WATER WILL BEGIN RUNNING OUT THE CONDENSATE DRAIN TRAP OUTLET
WHEN IT IS FULL. REFASTEN THE VENT DRAIN HOSE TO THE EXHAUSTER ASSEMBLY
ELBOW/DRAIN FITTING.
THE CONDENSATE DRAINAGE CONFIGURATION REQUIRES A VENT. IT TAKES LESS
THAN A ONE INCH RISE ANYWHERE ALONG THE HORIZONTAL ROUTE OF THE DRAIN
TUBE TO CREATE A VAPOR LOCK, WHICH WILL PREVENT CONDENSATE FROM
DRAINING AWAY FREELY, AND RESULT IN ERRATIC FURNACE OPERATION.
NOTE
The furnace, condensate trap and condensate drain line should be routed within the conditioned
space to avoid freezing of condensate and blockage of drain line.
Special precautions MUST be made if installing a condensing furnace in an area which may drop
below 32ºF (0ºC). This can cause improper operation or damage to the equipment. If the furnace
environment has the potential of freezing, the drain trap and drain line must be protected. In areas
where the temperature may be below 32ºF (0ºC) a self-regulating, shielded and waterproof heat tape
rated at 3 to 6 watt per foot (10 to 20 watt per meter) at 115 volt, 40ºF (4ºC) may be used to provide
freeze protection of the remaining condensate drain line. RV antifreeze can be used to protect the
drain trap if unit is going to be off for extended periods of cold weather. Wrap the drain trap and drain
line with the heat tape and secure with appropriate plastic ties. Follow the heat tape manufacturer's
recommendations. Prime the trap before furnace operation. The use of accessory drain trap heaters,
electric heat tape and/or RV antifreeze is recommended for these installations.
Locate the furnace so condensate fl ows downwards to the drain. Do not locate the furnace or its
condensate drainage system in any area subject to below freezing temperatures without proper
freeze protection.
If the drain line is routed through an area which may see temperatures near or below freezing,
precautions must be taken to prevent condensate from freezing within the drain line.
IMPORTANT:
CONNECT 1/2" TEE FITTING
(FIELD SUPPLIED) TO THE
OUTLET OF THE CONDENSATE
TRAP (FIGURE 15).
H16.4.2
35
IOM
W415-2308 / B / 11.04.19