Weil-McLain Evergreen EVG 220 Manual page 43

®
gas
System piping - Single Boiler Systems
See Advanced Manual for Multiple Boiler Systems
ZONE VALVE zoning –
(Shown with optional DHW piping)
This configuration is for zone valve systems using a boiler loop con-
nected as a secondary circuit off of a primary system loop.
1. Install a system circulator (supplied by installer) capable of
delivering the proper flow and head as shown.
2. The flow/check valve shown on the boiler outlet piping prevents
gravity circulation in the boiler loop during DHW heating.
Use at least the MINIMUM pipe size shown in
Figure 47, page 39 on all boiler loop piping (connecting
boiler to and from the primary/secondary connection,
item 14). Use only primary/secondary piping as
shown. Failure to follow these guidelines could result
in system problems.
Expansion Tank required
1. Provide a system expansion tank following the guidelines on
page 42.
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— A DHW tank can be connected as a zone if a
DHW tank is NOT already connected to the boiler. See notices
on page 129 to ensure compliance with the 2007 Energy Act. See
Advanced Manual to configure Boiler Pump to run during DHW
demands and change TARGET MOD SENSOR to System Supply.
3. DHW Priority operation— Using Priority 1 for DHW (default) will
turn off lower priorities during DHW calls. The MAX ON TIME
setting can be adjusted to limit how long this occurs. Use Priority
2 or 3 for DHW if DHW priority is not desired.
Overriding the Outdoor Reset function by setting control to
DHW mode when system is intended for space heating may
violate Section 303 of the 2007 Energy Act. See page 129
for compliance information and exemptions.
Controlling the circulators
1. The control can control up to four circulators (boiler circulator
and three others). Refer to Field wiring, beginning on page 52, for
instructions on wiring to circulators.
2. The factory default settings are: all three inputs are set up for
Space Heating ( Priority 2)
circulator output. For DHW Priority applications, wire aquastat
to Input 1 and assign to Priority 1. See Field wiring instructions,
beginning on page 52, for details.
LEGEND for Figure 52
1 Evergreen boiler
2 Indirect Water Heater, if used
3 Relief valve, supplied with boiler, field piped — MUST be
piped to boiler supply connection — see page 41 for informa-
tion
4 Relief valve piping to drain — see page 41.
5 DHW circulator
6 Isolation valves
7 System circulator
8 Expansion tank, diaphragm type, if used
9 Air separator
10 Flow/check valves or spring check
11 Purge/drain valves
(one drain valve shipped loose with boiler)
12 Auto air vent
Part number 550-100-131/0120
-
fired water boiler
primary/secondary
See Figure 52.
. Each input correlates to its respective
13 Zone valves
14 Primary/secondary connection (tees no more than 12
inches apart)
15 Expansion tank, closed type, if used (some chiller
systems may use a diaphragm-type expansion tank)
16 Water chiller
17 Check valve
18 Y-strainer
19 Balancing valve
20 Make-up water supply – Use applicable codes to deter-
mine if backflow preventers, pressure reducing valves,
and fill valves may be required
21 By-pass pressure regulator, Recommended for zone
valve systems unless other provision is made
— 220/299/300/399 Boiler Manual
Figure 52 Zone valve zoning —primary/secondary
connection — a system circulator is required
MINIMUM
Boiler loop pipe size
Evergreen 220 1¼"
Evergreen 299/300, 399 1½"
See CAUTION at left.
3. For more than 3-zones, use Weil-McLain WMZV zone valve
controller.
Connect zone valve end switches to Priority 2 input.
Connect system circulator to Circ. 2 output.
Use isolation relays if connecting 3-wire zone valve
end switches to the HEAT input.
Note: This is a common legend for all piping diagrams, Not
all items listed appear in every figure.
22 High limit temperature control, when required by local
code or for a radiant system.
23 DHW tank boiler water supply connection, when used
24 Zone circulator
25 DHW tank boiler water return connection, when used
26 Pressure/temperature gauge, supplied with boiler, field
piped
27 Heating circuits
28 Additional heating circuits,
29 Boiler circulator
30 Mixing device, if any
31 System supply and return sensors: Strap system sensors
to lines as shown, at least 6 pipe diameters (but no more
than 3 feet) from boiler connection tees.
32 Low Water Cut-off
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