Weil-McLain SVF 1500 Manual page 20

SVF
™
Series 1
Commercial Condensing Gas-Fired Water Boiler — Boiler Manual
Install water piping
ZONE VALVE zoning - Variable Primary
Flow
(Shown with optional DHW piping)
Figure 17 .
Th is confi guration is for applications that use a variable fl ow system pump.
1. Install a system circulator (supplied by installer) capable of deliver-
ing the necessary variable fl ow and head as shown.
2. Th e fl ow/check valve shown on the boiler outlet prevents gravity
circulation in the boiler loop during DHW heating.
3. A bypass with a diff erential pressure valve may optionally be used be-
tween the near boiler supply and return piping in high fl ow systems.
If used, ensure the System Supply Temperature sensor is placed
AFTER the bypass.
4. A fl ow switch is recommended if system fl ow could drop below the
minimum fl ow specifi ed on page 15 in Figure 10 . A 1"FNPT connection
is located on the boiler return pipe.
Expansion Tank required
1. Provide a system expansion tank following the guidelines on page 16 .
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. See Advanced Manual
to confi gure Boiler Pump to run during DHW demands and change
TARGET MOD SENSOR to System Supply.
2. System Priority choices:
a. DHW Priority – DHW is priority over space heating. Use Priority
1 for DHW; Priorities 2 and/or 3 for space heating. Th e 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.
Th e control will not run multiple priorities simultaneously.
c. No Priorities – Space heating and DHW can occur simultane-
ously at same Supply Max temperature. Use only if DHW is a zone
in system (see previous page). Assign DHW and Space heating to
the same Priority. Do not use outdoor reset for this application.
Controlling the circulators
1. Th e control can control up to four circulators (boiler circulator and three
others). Refer to Field wiring, beginning on page 59 , for instructions on
wiring to circulators.
2. Th e factory default sett ings are: all three inputs are set up for Space
Heating (Priority 2). Each input correlates to its respective circulator
TM
SVF
1 boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page 14 for piping details)
4 Relief valve discharge piping (see page 14 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 16 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
20
(continued)
Figure 17
See
output. For DHW applications, assign DHW inputs to determined
Priority (1, 2, or 3). Priority 1 is defaulted to DHW for DHW Prior-
ity applications.
3. For more than 3 zones, use Weil-McLain WMZV zone valve con-
troller.
Legend — Figure 17
13 Zone valves, typical
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters apart).
23 DHW secondary connector piping — no more than 8 pipe diameters apart.
24 System supply and return immersion sensors, 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 External drain/blowdown valve, when used.
32 Flow switch, by others
33 Strainer, recommended.
34 High fl ow systems may require a bypass pressure regulator/pressure reducing
valve to prevent excessive fl ow in heat exchanger.
Variable Primary Flow
Part number 550-100-250/0819