45
LEGEND
GMHB227
GMHB380
*
Pressure Relief Valve
30.00 psig
50 psig
A
Heating return connection
1" NPT
1
1/4"
NPT
B
Heating supply connection
1" NPT
1
1/4"
NPT
C
Gas connection
3/4" NPT
1" NPT
D
Drain connection for condensate
3/4 NPT
3/4 Hose
9.1 Central Heating System Connections
GMHB227 HEATING ONLY
WITH
OPTIONAL INDIRECT DHW
CONNECTION
GMHB380 HEATING ONLY
A
A
C
B
D
C
B
D
* Not Shown
PN 240012369, REV A [08/31/2018]
9 - START UP PROCEDURE