Greenheck Fan 90, HRE-20, 55, 45 manual Drain Trap

4 in.

2 in.

THE FOLLOWING COMPONENTS SHIP FROM GREENHECK WITH HRE (INSTALLATION, WIRING, AND POWER BY OTHERS)
PART DESCRIPTIONS	GREENHECK P/N	QTY.	HOLDING VA	INRUSH VA
JOHNSON CONTROLLER	07458032	1	-	-
OUTDOOR AIR SENSOR	07458298	1	-	-
24 HOUR TIMER	07381940	1	-	-
VALVE, WATER SUPPLY (A)	05461262	1	25	70
VALVE, DRAIN (B)	05461263	1	25	50
VALVE, SUMP DRAIN (C)	05461264	1	25	70

24V AC POWER AND WIRING

BY OTHERS

OUTDOOR AIR

SENSOR

	24VAC	SENSOR	COM
		JOHNSON CONTROLLER
		JC
	15	TIMER	A2
JC	B1		16
		T1
	A1		18
NC	COM
	SIDE OF HRE UNIT
DRAIN TRAP	SUMP DRAIN PIPE
	(TO EACH EVAP)

OUTDOOR AIR SENSOR

	TIMER
VA	VALVE "A"
	1/2 PIPE SIZE (NC)
VB	VALVE "B"
	1/4 PIPE SIZE (NO)
VC	VALVE "C"
	3/4 PIPE SIZE (NO)

Cooling coils are provided with a stainless steel drain pan with 3/4-in. female NPT drain connection. A drain trap must be connected to the drain connection to allow excess water to flow out of the drain pan.. More importantly, though, due to the negative internal static of the cooling coil compartment, installing the drain trap prevents outdoor air from being pulled into the drain pan and consequently forcing water out of the pan and into the unit..

To ensure the drain trap works properly, the trap height must account for the difference in static pressure between ambient conditions outside the unit and the internal

negative pressure of the cooling coil compartment.. For energy recovery units, an assumption of 3..0 in.. wg.. differential will be sufficient.. This would require a trap design as shown.. If the internal static is believed to be higher, consult factory..

Refer to local codes to determine drainage requirements.. If draining onto to roof, place a drip pad below drain to protect

roof.. If draining onto roof is not acceptable, a drain line must be attached to the trap.. The drain line must be pitched away from

the unit at least 1/8-in.. per foot.. On longer runs, an air break should be used to ensure proper drainage.. Local codes may require drainage into a waste water system..

Drainage problems not only occur from improper drain trap design, but also from lack of maintenance of the cooling coil compartment.. Algae can form in the drain pan and trap and cause reduced water flow, which can in turn result in backup into the system.. Regular maintenance will prevent this from occurring.. If the drains have a cleanout opening, be sure to close the opening after cleaning..

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