Weil-McLain SlimFit 2 Series Manual page 19

™
SlimFit
COMMERCIAL CONDENSING GAS
Install water piping
WATER CHILLER systems — ZONE VALVES
primary/secondary
1. The chiller must be piped in parallel with the boiler.
2. Use appropriate valves to prevent chilled medium from entering boiler.
3. Circulator zoning option — The space heating system can be zoned with
circulators if a separate circulator is supplied for the chilled water loop.
Install a separate circulator for each zone.
4. The flow/check valve shown on the boiler outlet piping prevents gravity
circulation in the boiler loop during DHW heating.
Use the
Figure 4, page 13 on all boiler loop piping (connecting boiler to
and from the primary/secondary connection, item 21).
sufficient flow. For other piping methods, see guides on page 13.
If antifreeze is used in the system, consider the effects of anti-
freeze on circulator sizing and DHW performance. Some local
codes may require double-wall DHW heat exchanger design.
Use only the antifreeze listed by Weil-McLain for use with this
boiler. See page 103 for details.
Chilled medium, if used, is piped in parallel with heating boiler
as shown in Figure 11. Use appropriate valves to prevent chilled
medium from entering boiler. If boiler is connected to heating
coils located in air handling units where they can be exposed
to refrigerated air, use flow control valves or other automatic
means to prevent gravity circulation during cooling cycle.
Expansion Tank required
1.
Provide a system expansion tank following the guidelines on page 14.
2. DO NOT use a closed-type tank if connecting to a water heater that is
equipped with an automatic vent.
Domestic Hot Water (DHW) tank, if used
1. DHW direct connection—Pipe from the near-boiler piping to the DHW
tank's boiler connections as shown.
2. DHW as zone— Not recommended for this application.
3. Priority of DHW/Space Heating:
a. DHW Priority – DHW is priority over space heating. Use Priority
1 for DHW; Priorities 2 and/or 3 for space heating. The control will
not run multiple priorities simultaneously.
b. Space Heating Priority – Space heating is priority over DHW. Use
Priorities 1 and/or 2 for space heating; Priority 3 for DHW. The
control will not run multiple priorities simultaneously.
Controlling the circulators
1. The control can control up to four circulators (boiler circulator and
three others). Refer to Field wiring, beginning on page 45, for instruc-
tions on wiring to circulators.
2. The factory default settings are: all three inputs are setup for Space
Heating (Priority 2). Each input correlates to its respective circulator
output. For DHW applications, assign DHW Input(s) to determined
1
SlimFit boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page 12 for piping details)
4 Relief valve discharge piping (see page 12 for details)
5 DHW circulator
6 Isolation valves
7 System circulator (see information above for wiring)
8 Diaphragm (or bladder) type expansion tank (see page 14 for piping of
closed-type expansion tank, if used)
9 Air separator [with automatic air vent only on systems using diaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler circulator
13 Zone valves, typical
15 Closed-type expansion tank
Part number 550-100-162/0815
-
FIRED WATER BOILER
(continued)
See Figure 11.
pipe size show n in
ensures the boiler loop will have
Legend — 11
—
Boiler Manual Series 2
Chilled water system plus optional DHW
piping
Priority (1, 2, or 3). Priority 1 is defaulted to DHW for DHW
Priority applications.
3. For more than 3-zones, use Weil-McLain WMZV zone valve
controller.
Connect zone valve end switches to a Space Heating Pri-
ority input, (default Priority 2) to use default settings
Connect system circulator to corresponding output.
Use isolation relays if connecting 3-wire zone valve
end switches to the inputs.
16 Water chiller
17 Check valve
18 Strainer
19 Balancing valve
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters apart)
24 Strap system supply and return sensors to lines as shown, at least 6 pipe
diameters (but no more than 3 feet) from boiler connection tees.
25 Systems using high-head pumps may require a bypass pressure regulator to
prevent damage to control valves.
26 Boiler drain valve, ¾" or larger
31 Install a union on the boiler supply and return connections as close as pos-
sible to the boiler to allow disconnection for service when required.
Items supplied with boiler
Items supplied by others
19