Sears 9MPD075F12B1, N9MP2050B12B1 CondensateDrain Trap, Condensate Drain Trap Freeze Protection

CondensateDrain Trap

This furnace removes both sensible and latent heat from the prod-

ucts of combustion. Removal of the latent heat results in con- densation of the water vapor. The condensate is removed from the furnace through the drains in the plastic transition and the vent fit- ting. The drains connect to the externally mounted condensate drain trap on the left or right side of the furnace.

The startup of a new furnace will involve a cycle or two of the fur- nace to properly prime the condensate trap with water. Until the trap is fully primed, some condensate will be pulled into the com- bustion blower. The furnace may cycle on the pressure switch con-

nected to the plastic transition box due to condensate buildup. After the trap is primed, the condensate will start draining from the furnace. The combustion blower will clear out any remaining con- densate in the blower housing through the vent fitting downstream of the blower. Note that the condensate trap can also be primed by pouring water into the 1/2" drain hose. Remove the1/2 " ID drain hose from either the gutter or the white PVC Tee Trap. Using a fun- nel pour eight (8) ounces of water into 112" ID drain hose.Water will

flow through the drain hose and into the condensate drain trap. This will prime both the vent and the transition sides of the trap. Re- connect the 1/2, ID drain hose to the original component, either the gutter or the PVC Tee Trap.

The condensate drain trap supplied with the furnace MUST be used. The drain connection on the condensate drain trap is sized for 3/4" PVC or CPVC pipe, however alternate 1/2" CPVC (nominal 5/8" O.D.) or vinyl tubing with a minimum inner diameter (I.D.) of 5/8" may also be used, as allowed by local codes. Alternate drain pipes and hoses may be used as allowed by local codes.

The drain line must maintain a I/4" per foot downward slope toward

the drain. 114"per foot is recommended. Installation of an overflow

line is recommended when the 114" per foot slope to the conden-

sate drain cannot be maintained. See Figure 18 for proper routing and installation of the overflow.

DO NOT trap the drain line in any other location than at the con- densate drain trap supplied with the furnace.

FROZEN AND BURST WATER PIPE HAZARD

Failure to do so could result in burst water pipes, serious property damage and/or personal injury.

If a condensate pump is installed, a plugged

condensate drain or a failed pump may cause the furnace to shut down. Do not leave the home

unattended during freezing weather without turning off water supply and draining water pipes or otherwise protecting against the risk of frozen pipes.

If possible DO NOT route the drain line where it may freeze. The drain line must terminate at an inside drain to prevent freezing of the condensate and possible property damage.

1.A condensate sump pump MUST be used if required by lo- cal codes, or if no indoor floor drain is available. The con-

densate pump must be approved for use with acidic condensate.

2.A plugged condensate drain line or a failed condensate pump will allow condensate to spill. If the furnace is installed where a condensate spill could cause damage, it is recom- mended that an auxiliary safety switch be installed to pre- vent operation of the equipment in the event of pump failure or plugged drain line. If used, an auxiliary safety switch should be installed in the R circuit (low voltage) ONLY.

3.If the auxiliary switch in the condensate pump is used, the furnace may shut down dueto a blocked condensate line or failed pump. To prevent frozen water pipes see the "Frozen Water Pipe Hazard" section on Page 4 of this manual.

Condensate Drain Trap Freeze Protection

Special precautions MUST be made if installing furnace in an area which may drop below freezing. This can cause improper opera- tion or damage to the equipment. If the the furnace environment has the potential of freezing, the drain trap and drain line must be protected. Use 3 to 6 watt per foot at 11 5 volt, 40 ° F self-regulating shielded and waterproof heat tape. Wrap the drain trap and drain line with the heat tape and secure with the ties. Follow the heat

tape manufacturer's recommendations.

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