Install Water Piping - Weil-McLain Evergreen EVG 70 Manual

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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
Use piping unions near boiler
Recommend installing 1" NPT piping unions on boiler outlet
and return to facilitate future service requiring heat exchanger
removal. Pipe unions are Not included with the boiler.
Additional controls, if required
The control uses temperature sensors to provide both
high limit protection and modulating temperature
control.
The control's high limit function requires
manual reset
require additional external controls for high limit
and/or low water cutoff protection.
Additional limit controls
Following standard industry practices, if installation is to comply
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
control operating limit function shuts the boiler down at
195°F, or lower if set to a lower value.)
Multi-temperature systems
system 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 the control
external limit circuit terminals.
Low temperature materials — If using temperature-
limited materials (such as PEX tubing) in system
piping, it is recommended to protect the system
with limit controls that are wired to the controls
external limit circuit.
2. See instructions beginning on page 54 for wiring information.
3. If using a manual reset limit control or wiring in the manual
reset circuit, set EVG control boiler limit at least 20°F less than
the external manual reset limit (i.e., set EVG control no higher
than 180°F for a 200°F external limit, for example).
Separate low water cutoff
1. A separate low water cutoff device is recommended when the
boiler is installed above piping level, and may be required by
certain state or local codes or insurance companies. Consult
local requirements to determine. See the NOTICE above
regarding the inherent protection provided by the Control
module. A low water cut-off is standard equipment with the
®
Evergreen boiler.
2. The Control's integral protection is accepted in many
jurisdictions as meeting the requirement for low water
protection. See page 59 for details.
40
as-fired water boiler —
. Some codes/jurisdictions may
— If the heating
Boiler Manual
70/110/155
3. When required, use a low water cutoff designed for water
installations. Electrode probe-type is recommended.
See Replacement parts section at the end of this manual for
the Weil-McLain low water cut-off kit.
4. Install the low water cut-off (supplied with boiler) in a tee in
the supply piping above boiler.
5. See fi eld wiring instructions beginning on page 54 for wiring
additional limit controls.
Backfl ow preventer
Use backfl ow preventer in the cold water supply piping if required
by local codes.
System/zone pipe sizing
(Baseboard, convectors or cast iron radiators ONLY)
For residential space heating applications (other than radiant
heating or unit heaters) ONLY, you can use the sizing suggestions
in Figure 43 .
Figure 43
Suggested pipe sizing for system headers and
zone piping — RESIDENTIAL with baseboard,
convectors or cast iron radiators ONLY (20°F
temperature rise)
EVG Models
70/110
155
Recommendations are based on a 20°F temperature drop
through the system.
Suggested maximum load per zone
Copper pipe and
baseboard size
¾"
1"
Size zone circulators to handle the required fl ow and head
loss for each zone.
System water pip ing methods
Direct connection piping to boiler
It is recommended, but not required, to use primary/
secondary piping to the boiler. Using primary/
secondary piping will provide the most effi cient
and reliable operation of the boiler and the heating
system.
Installations using direct connection piping layout
should:
1. Read the NOTICES and guidelines beginning on page
41 to determine if the system is eligible for this piping
strategy.
2. If eligible, reference suggested piping layouts on pages 42
and 43 .
3. Use primary/secondary piping if system ineligible.
System header
1" or larger
1¼" or larger
Maximum recommended
feet of baseboard
67
104
Part number 550-100-191/0917