Figure 15
Zone valve zoning plus optional DHW piping
SVF
™
Series 1
Commercial Condensing Gas-Fired Water Boiler
— Boiler Manual
Part number 550-100-250/0819
18
Zoning with zone valves — alternate
High-fl ow-rate/high-head-loss DHW
circuits
See Figure 15 .
Th
is confi guration is for applications requiring DHW circuit fl ow rates
higher than allowable for the boiler, or for high pressure-drop coil-type
DHW tanks, connect the piping as in Figure 15 . Th
e DHW water only
fl ows through the secondary circuit connection piping. Th
e primary/
secondary piping shown ensures the boiler loop will have suffi
cient fl ow.
It also avoids applying the high head of the boiler circulator to the zone
valves.
1. Make sure to size the connection piping ( Figure 15 , item 23) to handle
the total fl ow it must handle.
2. Install a system circulator (supplied by installer) capable of delivering
the proper fl ow and head as shown.
3. Th
e fl ow/check valve shown on the boiler outlet piping prevents gravity
circulation in the boiler loop during DHW heating.
Use
at least
the
-).)-5-
pipe size shown in Figure 11, page 16
on all boiler loop piping (connecting boiler to and from the pri-
mary/secondary connection, item 21).
0RIMARYSECONDARY
piping shown
ensures the boiler loop will have suffi
cient fl ow.
For other piping methods, see guidelines starting on page 15 .
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.
2. DHW as Zone – not applicable to this application.
3. 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 simultaneously
at same Supply Max. temperature. Use only if DHW is a zone in
system. Assign DHW and Space heating to 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 circula-
tor output. For DHW applications, assign DHW inputs to determined
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
Priority input, , (default Priority 2) to use default sett ings.
Connect system circulator to corresponding output.
Use isolation relays if connecting 3-wire zone valve
end switches to the inputs.
Legend — Figure 15
1
SVF
TM
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
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.
33 Strainer,
recommended.
Install water piping
(continued)
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