Aprilaire 1770A, 1750A MECHANICAL INSTALLATION continued, Whole-Homeinstallation, Drain Trap

MECHANICAL INSTALLATION (continued)

DRAIN

1.Adjust feet of dehumidifier to allow a 2-1/2” minimum clearance for drain trap.. See Figure 6.. Use the 90° elbow if necessary for clearance restrictions.. See Figure 7..

2.Use PVC primer and cement for drain assembly to the dehumidifier drain outlet..

3.Complete assembly by piping the 3/4” PVC trap to a drain or condensate pump.. Make sure the drain line has a constant downward slope and is not kinked..

4.To prime the drain trap and to verify the drain line is not blocked, slowly pour a pint of water into the dehumidifier drip pan located below the coil..

CAUTION

1.Drain trap must be primed with water before use.

2.A condensate pan with a float switch is required in attic installations.

Figure 6 – Drain Trap

Drain Outlet
High Side	Arrows on
Drain Trap	trap show
	water flow
	direction

2-1/2	Low Side
	90-961
Figure 7 – Drain Trap with 90° Elbow
	Drain Trap
90° PVC Elbow
High Side	Low Side
	90-961

Float Switch

If the dehumidifier is installed in an attic or another location requiring leak protection, the unit should be placed in a condensate pan with a normally closed, condensate overflow safety switch (float switch).. Remove the jumper from the float switch terminals on the control board and wire the float switch to the terminals.. See Figure 8..

Whole-Home installation

Figure 8 – Float Switch Wiring

FLOAT

SWITCH

LOW VOLTAGE NORMALLY

CLOSED FLOAT SWITCH

90-1429

This installation is used when the HVAC equipment conditions the whole home.. Using the dehumidifier in conjunction with the HVAC system is the optimum solution for year-round, whole-home control.. This installation is typically in basement or attic locations.. Ducting the unit to the return and supply, where air is pulled from the return duct, dehumidified, and discharged to the supply duct, is the most common setup.. Additional configurations include only ducting the dehumidifier outlet to the supply or ducting the inlet and outlet to the return duct.. In the latter case, the HVAC fan must be activated during dehumidification..

Required Components

Duct Work

18 – 22 AWG Wire

Optional Components

Condensate Pan & Normally Closed Float Switch

Model 70 Living Space Control

Third-Party Control

6