Table of Contents
Advertisement
WM97+
-
gas
fired water boiler
Install water piping
Use two wrenches when tightening water piping
at boiler, using one of the wrenches to prevent
the boiler interior piping from turning. Failure to
support the boiler piping connections to prevent
them from turning could cause damage to boiler
components.
General piping information
Additional controls, if required
The WM97+ control uses temperature sensors to
provide both high limit protection and modulat-
ing temperature control.
function requires manual reset
risdictions 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 constructed to
prevent a temperature setting above 200°F in system supply
piping between boiler and isolation valve. (Note that the
WM97+ 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 a WM97+ control external limit
circuit terminals.
2. See instructions beginning on page 64 for wiring information.
3. If using a manual reset limit control or wiring in the manual
reset circuit, set WM97+ control boiler limit at least 20°F less
than the external manual reset limit (i.e., set WM97+ control
no higher than 180°F for a 200°F external limit, for example).
Backflow preventer
1. Use backflow preventer in the cold water supply piping if
required by local codes.
Internal expansion tank (WM97+70 or
110 only, not on WM97+155)
1. The WM97+70 and 110 boilers are equipped with an internal
expansion tank, factory charged to 12 PSIG.
Part number 550-142-120/0113
— Boiler Manual
The control's high limit
. Some codes/ju-
— If the heating sys-
2. The internal expansion tank is suitable for most systems with
total volume of 15 gallons or less. See page 42 for suggestions
for adding additional a supplementary expansion tank for
higher-volume systems.
3. The maximum operating pressure of the internal expansion
tank is 42.5 PSIG.
The internal expansion tank isolation valve must
be turned off during hydrostatic testing.
The internal expansion tank valve
DURING ALL TIMES OF OPERATION.
System water piping methods
Except as shown on page 44, all piping methods
shown in this manual use primary/secondary con-
nection to the boiler loop.
These designs ensure proper flow through the
WM97+ boiler to provide the most efficient and
reliable operation of the boiler and the heating
system.
System/zone pipe sizing
(Baseboard, convectors or cast iron radiators ONLY)
1. For residential space heating applications (other than radiant
heating or unit heaters) ONLY, you can use the sizing sug-
gestions in Figure 38.
Figure 38
Suggested pipe sizing for system headers
and zone piping — RESIDENTIAL with
baseboard, convectors or cast iron radiators
ONLY (20°F temperature rise)
WM97+ Model
70
110 or 155
Recommendations are based on a 20°F temp 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.
MUST BE OPEN
System header
1" or larger
1¼" or larger
Maximum recommended
feet of baseboard
106
179
– 37 –
Advertisement
Table of Contents
