User Guide

Part number 550-100-325/0718
34
AquaBalance
®
SERIES 2 WALL MOUNT GAS-FIRED WATER BOILER — Boiler Manual
16 Install water piping (continued)
This boiler is NOT intended for connection with a
refrigeration system.
General piping information
Additional controls, if required
The control uses temperature sensors to provide
both high limit protection and modulating
temperature control.
The control’s high limit
function requires manual reset
. Some codes/
jurisdictions may require additional external
controls for high limit and/or low water cutoff
protection.
Additional limit controls
Following standard industry practices, if installation is to comply
with ASME or Canadian requirements, an additional high tem-
perature limit may be needed. Consult local requirements for other
codes/standards to determine if needed.
1. Install a manual reset high temperature limit to prevent a
temperature above 200°F in system supply piping between
boiler and isolation valve. (Note that the control operating
limit function shuts the boiler down at 195°F, or lower if set
to a lower value.)
Multi-temperature systems — If the heating sys-
tem includes circuits that require lower temperature
water (radiant slab circuits, for example) as well as
higher temperature circuits, it is recommended to
protect low temperature circuits with limit controls
that are wired to the control external limit circuit
terminals.
Low temperature systems — If using temper-
ature-limited materials (such as PEX tubing) in
system piping, it is recommended to protect the
system with limit controls that are wired to the
controls external limit circuit.
2. See instructions beginning on page 48, for wiring information.
3. If using a manual reset limit control or wiring in the manual
reset circuit, set boiler control limit at least 20°F less than the
external manual reset limit (i.e., set control no higher than
180°F for a 200°F external limit, for example).
Backflow preventer
Use backflow preventer in the cold water supply piping if re-
quired by local codes.
System/zone pipe sizing
(Baseboard, convectors or cast iron radiators ONLY)
For residential space heating applications (other than radiant
heating or unit heaters) ONLY, you can use the sizing suggestions
in Figure 44.
Studies have indicated that dangerous bacteria
can form in potable water distribution systems
if certain minimum water temperatures are not
maintained. Contact local health department for
more information.
Figure 43 Domestic Piping - Brazed Plate Heat
Exchanger - Ports 2 and 4
Model
System header
AB-80/120 1” or larger
AB-155 1-1/4” or larger
Recommendations are based on a 20°F temperature drop
through the system.
Suggested maximum load per zone
Copper pipe and
baseboard size
Maximum recommended
feet of baseboard
¾” 67
1” 104
Size zone circulators to handle the required flow and head
loss for each zone.
Carbonate must be treated with a “Water Softener” prior
to entering the boiler. Plugging of the domestic system by
scaling or accumulation of dirt is not the responsibility of
Weil-McLain, and suitable steps must be taken to avoid it.
• Cleaning- refer to the installation manual maintenance
section for the proper cleaning procedure for the plate
DHW heat exchanger, and the required cleaning frequency.
Figure 44 Suggested pipe sizing for system headers
and zone piping — RESIDENTIAL with
baseboard, convectors or cast iron radiators
ONLY (20°F temperature rise)