Piping The Boiler; Wiring The Boiler; Control System - Weil-McLain CER Series 2 Installation Instructions Manual

CER Series 2 Electric-Hydronic Boilers Installation Instructions
Pre-installation

Piping the boiler

After the boiler is secured to the wall, attach the supply
and return piping. Refer to Table 2 for minimum pipe
sizes.
Install manual shut-off valves in the supply and return
lines to facilitate servicing the boiler. Model CER boilers
are provided with a built-in air separator. Refer to the
boiler line drawings and proceed as follows:
1. Install the pressure-temperature gauge and ¾"-¼"
bushing in the 1¼" x 1¼" x ¾" tee installed on the
boiler supply connection. See "Dimensions" on
page 13.
2. The ¾" tapping, located to the left of the supply
tapping, must be used for either an automatic
venting device or piped directly to a standard closed
expansion tank.
3. Install the pressure relief valve in the ¾" tapping
located on the top left hand side of the boiler (see
"Dimensions" on page 13).
4. A ¾ " tapping located in the bottom of the vessel is
supplied for draining the boiler.
5. Connect the system supply piping to the tapping
located at the right on the top of the boiler casting.
6. Connect the system return piping to the tapping
located in the bottom, left side of the casting.
Table 2
(Recommended minimum pipe size with 20°F
temperature rise through boiler.)
Boiler
model
number
CER-24
CER-32
CER-40
4
Pipe relief valve discharge line near
floor close to floor drain to eliminate
potential of severe burns. Do not
pipe to any area where freezing
could occur. Do not plug valve or
place any obstruction in discharge
line.
Minimum pipe sizes and flow rates
Flow rate Supply
GPM pipe size
8.2 1"
10.9 1¼"
13.7 1¼"
continued

Wiring the boiler

The Model CER electric-hydronic boilers are pre-wired
and require only two wires for connection of single
phase boilers and three wires for connection of 3-phase
boilers. Aluminum wire must not be used. Add
additional 120 volt service must be provided to utilize
the circulator control provided in the boiler. See wiring
diagram on page 6 for single phase or page 7 for 3-phase.
An opening is provided in the left side of the jacket top
panel for the field wiring. Refer to "Dimensions" and
"Ratings" on page 13, for recommended wire sizes.
All wiring must conform to the requirements of the
National Electrical Code and any additional National,
State or Local Code Requirements having jurisdiction.
All safety circuit wiring should be N.E.C. Class 1. Do
not use aluminum wire.
When a CER boiler is used in a zoned system, the zone
valves must be powered from an independent source,
and have electrically isolated end switches or isolating
relays wired in parallel to the boiler thermostat
terminals.

Control system

The control system for the CER electric boiler has
electronic and thermal time delays, which are employed
to sequence elements on and to sequence elements off
in reverse order. The contactors used in the system
Return
disconnect all current from the heating elements.
pipe size
The circulator control utilizes a single pole relay.
Low and high limit functions are combined in a dual
1"
limit control. The control system is operated from a
1¼"
low voltage transformer.
1¼"
Electric shock hazard. Can cause
severe personal injury or death if
power source, including service
switch on boiler, is not disconnected
before installing or servicing.
Do not attempt to power zone valves
from the transformer in the boiler
control system.
Part number 550-141-402/0801