Weil-McLain Aqua Balance WMB-155 Manual page 46

W
TM
AquaBalance
18 Multiple boiler installations
DHW tank piping with multiple
WMB boilers
DHW direct connection—single tank
1. If BTUH output of a single boiler is sufficient for the
DHW tank/demand, pipe the indirect water heater to
the last boiler in the firing sequence. This will allow the
previous boilers to continue space heating while the last
boiler delivers DHW priority.
2. Pipe from the near-boiler piping to the DHW tank's
boiler connections as shown in Figure 50, page 41.
3. Connect the DHW tank aquastat directly to the DHW
input on the last boiler in the sequence.
Figure 55
Piping layout—typical piping for multiple boilers (4-boiler system shown) with DHW storage heaters grouped as
zone in secondary loop off primary system loop. (Heating Only)
46
M -
ALL OUNT GAS FIRED WATER BOILER
—
Boiler Manual
(continued)
When using a multiple-boiler control with lead boiler
rotation, it is recommended that the boiler connected to
the DHW tank is always set as the last boiler to operate
in the sequence so that space heat can be maintained
during times of DHW demand.
DHW tanks as zone—multiple tanks
1. If using multiple DHW tanks or multiple banks of tanks, pipe the
tanks to the primary system loop with a secondary connection as
shown in Figure 55.
2. DHW tanks are zoned with circulators as shown.
3. If DHW priority is required, use separate zone controllers for
DHW and space heating.
Part number 550-100-305/0118