Weil-McLain PER 550-141-396-0801 User Manual
PER Series 3
Electric-Hydronic Boilers
Installation Instructions
Installer
Read all instructions before
installing. Follow all instructions in
proper order to prevent personal
injury or death.
• Consider piping and installation when determining
boiler location.
• Any claims for damage or shortage in shipment
must be filed immediately against the
transportation company by the consignee.
These Instructions must be used only by a qualified installer/service
technician. R ead these instructions completely before beginning. Fail ure to
follow these instructions can cause severe personal injury, death or
substantial property damage.
When calling or writing about the boiler— Please have the boiler model
number from the boiler rating label and the CP number from the boiler
jacket. You may list the CP number in the space pro vided on the Installation
and service certificate found on page 9.
User
• This manual is for use only by
your qualified heating installer/
service technician.
• W e rec ommend regular service
by a qualified service
technician, at least annually.
Part number 550-141-396/0801
PER Series 3 Electric-Hydronic Boilers Installation Instructions
Please read before proceeding
Hazard Definitions
The following defined terms are used throughout these Instructions to b ring attention t o the prese nc e of hazards
of various risk levels, or to important information concerning the life of the product.
Indicates presence of hazards that will cause severe personal injury , death or substantial property
damage.
Indicates presence of hazards that can cause severe personal injury , death or substantial property
damage.
Indicates presence of hazards that will or can cause minor personal injury or property damage.
Indicates special instructions on installation, operation or maintenance that are important bu t
not related to personal injury or property damage.
Failure to adhere to the guid elines on this pag e can res ult in sev er e pers onal inj ury, death
or substantial property damage.
When servicing boiler —
• To avoid electric shock, disconnect electrical supply before performing maintenance.
• To avoid severe burns, allow boiler to cool before performing maintenance.
• The boiler contains fiberglass materials. Use care when handling these materials per instructions on page
11 of this manual.
Boiler operation —
• Do not block flow of ventilation air to boiler. Will cause components to overheat.
• Should overheating occur , do not disc onnect electrical supply to circulator . Instead, sh ut off the electrical
supply at a location external to the appliance.
• Do not use this boiler if any part has been under water. Immediatel y call a qualified service technician to
inspect the boiler and to replace any part of the control system that has been under water.
Boiler water —
• Do not use petroleum-based cleaning or sealing compounds in boiler system. This can result in substantial
property damage.
• Do not use "homemade cures" or "boiler patent medicines". Serious damage to boile r, personnel and/or
property may result.
• Continual fresh makeup water will reduce boiler life. Mineral buildup in section reduces heat transfer,
overheats cast iron, and causes section failure. Addition of oxygen and other gases can cause internal
corrosion. Leaks in boiler or piping must be repaired at once to prevent makeup water.
• Do not add cold water to hot boiler. Thermal shock can cause sections to crack.
Glycol — potential fire hazard —
All glycol is flammable when exposed to high temperatures. If glycol is allowed to accumulate in or around
the boiler or any other potential ignition source, a fire can develop. In order to prevent potential severe
personal injury, death or substantial property damage from fire and/or structural damage:
• Never store glycol of any kind near the boiler or any potential ignition source.
• Monitor and inspect the system and boiler regularly for leakage. R epair any leaks immediately t o prevent
possible accumulation of glycol.
• Never use automoti ve antifreeze or ethylene glyc ol in the system. U sing these glycols can lead to hazardous
leakage of glycol in the boiler system.
2
Part number 550-141-396/0801
PER Series 3 Electric-Hydronic Boilers Installation Instructions
Pre-installation
General instructions
The Weil-McLain Model PER electric-hydronic boilers
are assembled units designed for use in forc ed hot water
heating systems. The suggested design temperature rise
through the boiler is 20°F. The PER boiler is a complete
package including the circulator and expansion tank.
Low flow rates through the boiler at elevated
temperatures should be avoided. The structure to be
heated should be insulated in the conv entional manner
used in your area for electrically heated buildings. Boiler
must be installed in accordance with these instructions
so as not to void our warranty.
Open the boiler crate and check the contents. In the
event of shortage or damage, notify the transportation
company immediately.
Locating the boiler
The compact construction of the electric-hydronic
boiler permits installation in an alcove, storeroom or
other small area. The location chosen should have
convenient electrical service.
Allow sufficient clearance above and below the boiler
cabinet to permit installation of supply and return
piping. A minimum of 6 inches is required at the top o f
the boiler for installation and accessories. A clearance
of 10 inches is required on the right hand side for
removal of the elements.
Expansion tank sizing
Undersized expansion tanks cause system water to be
lost from relief valve and mak eup wat er added through
fill valve. Eventual section failure can result.
If a Fill-Trol system is used, refer to Table 1 for proper sizing. If Fill-Trol
action is not desired, size the expansion tank ac cording to the wat er volume
of the system. If a standard closed expansion tank (without a diaphragm)
is used, the air vent tapping on the boile r casting makes a co nv enient point
of connection. The No. 109 Fill-Trol is furnished as standard equipment.
T ab le 1 Expansion tank sizing (Tank sizing based on 200 °F
average system temperature.)
Boiler
model
number
PER-15 No. 109 No. 15
PER-20 No. 109 No. 15
PER-25 No. 109 No. 15
Note: Gravity systems converted to a forced hot water system usually require
additional compression tank capacity.
Standard Fill-Trol tank
(for series loop or one-pipe system
with convector baseboard)
Additional Ex-Trol tank
(for cast-iron radiators or
cast-iron baseboard)
Mounting the boiler
Normally, the boiler will be installed against a frame or
masonry wall. If the wall surface is rough or uneven, it
may be necessary to mount plywood on the wall, then
mount the boiler on the plywood. Refer to
“Dimensions” on page 12 and “Ratings” on page 13, and
note the boiler weight. Be sure that the wall structure
will support the boiler and its piping.
The 9/16" top mounting holes and 5/16" lower mounting
holes are on 16-inch centers to permit installation on
studs in standard wall construction. The use of ¼" x
2½" lag screws is recommended for mounting the boiler .
The head diameters of the top two screws must not
exceed 9/16".
1. Locate the top mounting holes so that the boiler
will be level. Install the screws so that the heads
protrude ¾" from the wall.
2. Raise the boiler to mounting position by placing a
board across the bottom of the boiler or by grasping
the lower left and right inside corners. Do not
attempt to lift the boiler by grasping the bottom
jacket cross tie.
3. Place the top brackets o ver the lag scr ews and then
install screws through the lower mounting holes.
The top screws can now be tightened.
Hydrostatic pressure test
Pressure test boiler before attaching piping or electrical supply.
1. Install air vent in tapping on top of boiler .
2. Plug remaining tappings, including relief valve opening.
3. Connect water supply. Fill boiler and purge all air. For more than 10
minutes, pressure-test at 1½ times maximum working pressure.
Do not leave boiler unattended. Cold water fill could
expand and cause excess pressure, resulting in severe
personal injury, death or substantial property damage.
4. Check for maintained gauge pressure. V isually check for leaks if gauge
pressure drops.
5. Drain boiler and repair leaks if found.
Leaks must be repaired at once. Failure to do so can
damage boiler , resulting in substantial property damage.
6. Retest boiler after repairing leaks.
7. Remove testing plugs and air vent.
Do not use petroleum-based cleaning or sealing
compounds in boiler system. S evere damage to boiler
will result, causing substantial property damage.
Part number 550-141-396/0801
3
PER Series 3 Electric-Hydronic Boilers Installation Instructions
Pre-installation continued
Piping the boiler
After the boiler is secured to the wall, attac h the suppl y
and return piping. Refer t o Table 2 for minimum pipe
sizes.
Install manual shut-off valves in the supply and return
lines to facilitate servicing the boiler. Model PER boilers
are provided with a built-in air elimination system using
a float-type automatic air vent. Refer to the boiler line
drawings and proceed as follows:
1. Install the pressure-temperatur e gauge and ¾"-¼"
bushing in the 1¼" x 1¼" x ¾" tee installed on the
boiler supply connection. See “Dimensions” on
page 12.
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 12). Pipe the relie f valve
outlet to a floor drain or near the floor . Do not pipe
the relief valve to any area where freezing
temperatures might be encountered.
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.
4. Connect the system supply piping to the tapping
located at the right on the top of the boiler casting.
5. Connect the system return piping to the circulato r
flange. When solder fittings are used, be sure that
the gasket is not between the flanges when the solder
connection is made.
6. A Fill-Trol system is supplied with PER boilers
follow the instructions attached to the valve.
Table 2 Pipe sizes and flow rates
(Recommended minimum pipe size with 20°F
temperature rise through boiler.)
Wiring the boiler
Electric shock hazard. Can cause
severe personal injury or death if
power source, including service
switch on boiler , is not disco nnected
before installing or servicing.
The Model PER electric-hydro nic boilers are pre-wired
for use with 240-volt, single phase, 50/60-hertz power.
Refer to Figure 1 on page 13 fo r the r eduction in boiler
capacity when the line voltage is less than 240 volts.
An opening is provided in the left side of the jacket top
panel for the field wiring. Refer to Dimensions, page
12, and Ratings, page 13, for recommended wire sizes.
All wiring must conform to the requirements of the
National Electrical Code and any additional Nat ional,
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 PER 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.
Do not attempt to power zone valves
from the transformer in the boiler
control system.
Control system
The control system for the PER electric boiler has
electronic and thermal time delays, which are employ ed
to sequence elements on and to sequence elements off
in reverse order. The contactors used in the system
disconnect all current from the heating elements.
The circulator control utilizes a single pole relay.
Low and high limit functions are combined in a dual
limit control. The control system is operated from a
low voltage transformer.
Boiler
model
number
PER-15 5.20 ¾" ¾"
PER-20 6.90 1" 1"
PER-25 8.60 1¼" 1¼"
4
Maximum
flow rate
GPM
Minimum
supply
pipe size
Minimum
return
pipe size
Part number 550-141-396/0801
PER Series 3 Electric-Hydronic Boilers Installation Instructions
Sequence of operation
Call for heat
1. The thermostat contacts close, energizing the first contactor (2K), the circulator relay
(1K), and the heater in the first thermal time delay (H1).
2. Approximately 15 seconds later, the thermal delay contacts (1C) close energizing the
electronic circuit inside the first electronic time delay (ED1).
3. After approximately 2.5 minutes, the first electronic time delay energizes the second
contactor (3K) and the second thermal time delay heater (H2).
4. This sequence continues until all contactors ar e energized or until the call for heat ends.
Call for heat satisfied
5. The thermostat contacts open, de-energizing the first contact or (2K), the circulator relay
(1K), and the heater in the first thermal time delay (H1).
6. After a minimum of 10 seconds, the contacts in the first the rmal delay (1C) open, instantly
de-energizing the electronic time delay (ED1), the second c ontacto r (3K), and the second
thermal delay heater (H2).
7. This sequence continues until all elements are de-energized.
Limit control operation
8. If the high limit setting is exceeded, the transformer secondary circuit is opened and all
contactors are de-e nergized instantly . It is recommende d that the “high” side of the contro l
be set at 220°F. The “low” side should be set according to the design requirements of the
structure to be heated but never less than 20°F below the “high” setting. The differential
control should be set at a minimum of 20°F.
Part number 550-141-396/0801
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