Weil-McLain Aqua Balance WMB-155 Manual page 36

W
TM
AquaBalance
16 Install water piping
• Hard Water- To prevent the formation of scale on the inside
of the plate DHW heat exchanger and other components in
the domestic hot water system, water with hardness higher
than 50 ppm Calcium 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.
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.
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.
function requires manual reset
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 com-
ply with ASME or Canadian requirements, an additional high
temperature 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
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.
36
M -
ALL OUNT GAS FIRED WATER BOILER
(continued)
The control's high limit
. Some codes/
— If the heating sys-
—
Boiler Manual
Low temperature systems
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 50, 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
required 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 sugges-
tions in Figure 44.
Figure 44
Suggested pipe sizing for system headers
and zone piping — RESIDENTIAL with
baseboard, convectors or cast iron radiators
ONLY (20°F temperature rise)
Model
WMB-80/120
WMB-155
Recommendations are based on a 20°F temperature drop
through the system.
Suggested maximum load per zone
Copper pipe and
baseboard size
¾"
1"
Size zone circulators to handle the required flow and head
loss for each zone.
System water piping methods
Primary/secondary piping to boiler
Using primary/secondary piping will provide the most efficient
and reliable operation of the boiler and the heating system.
1. Use information beginning on page 37 to size pump for
proper flow through the boiler.
2. Reference suggested piping layouts on pages 38-43.
— If using temper-
System header
1" or larger
1-1/4" or larger
Maximum recommended
feet of baseboard
67
104
Part number 550-100-305/0118