Page 1
MODEL EH-M3 ELECTRIC BOILER
Multi-stage electronic control with energy saving and other features.
EH-08-138-M3 through EH-20-138-M3, single phase, 3 wire, 120/208V
EH-08-134-M3 through EH-20-134-M3, single phase, 3 wire, 120/240V
EH-12-348-M3 through EH-20-348-M3, three phase, 4 wire, 120/208V
EH-12-344-M3 through EH-20-344-M3, three phase, 4 wire, 120/240V
OPERATION AND INSTALLATION INSTRUCTIONS
CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PAGE
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Air Eliminator and Expansion Tanks . . . . . . . . . . . . . . . . . .2
Flow Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Wiring (Warning: DO NOT turn on breakers on unit) . . . . . . . . .2
Wall Thermostat Flow Switch and Circulator . . . . . . . . . . .2
Service Connections and Electrical Ratings . . . . . . . . . . . .2
“Rough-In” Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Fill System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Air Elimination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Bypass Flow Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Check for Proper Boiler and System Operation . . . . . . . . .6
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Periodic Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Control Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Appendix A, B, C, & D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
IMPORTANT:
This manual must be left with owner and should be hung
on or adjacent to the boiler for reference.
Publication No. EH-M3-40 Rev. A • Printed in U.S.A. 1014
Part No. 793860000
MINITRON
LISTED
89C4
Heating Contractor
Address
Phone Number
Model Number
Serial Number
Installation Date
Page 2
2 EH-M3-40 Boiler Operation and Installation Instructions
DESCRIPTION
The Minitron boiler is a low pressure hot water heating electric boiler.
The control is a two stage electronic control with energy saving and
other features. The heating elements are sheathed resistance type. The
heat exchanger is cast-iron. The heat exchanger is constructed, inspected, and stamped in accordance with Section IV of the American Society
of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. In
addition, the Minitron Boiler is equipped with a safety relief valve conforming to ASME requirements and two separate limit controls conforming to U.L. requirements. The Minitron boiler is Underwriters'
Laboratories, Inc. listed.
MOUNTING THE BOILER ON A WALL
Be sure that the wall is vertically plumb and capable of carrying the
weight of the boiler and the system piping, when full of water. The boiler
full of water is approximately 100 lbs. Add to this the weight of the system piping that the boiler will be supporting.
Be sure that there are studs available in the proper locations, for securing the boiler wall bracket and back panel.
(See Figures 1 and 1a).
For wood stud walls, use lag screws or wood screws with a coarse
thread and a minimum of 3” in length.
For metal stud walls, use toggle-style bolts that are specifically designed
for such and maximum capacity exceeds the weight of the boiler and the
system piping when full of water.
DO NOT use anchors driven into sheetrock to hold the boiler up on the
wall. If mounting the boiler on a cement wall, use anchors that are
specifically designed for such, and maximum capacity exceeds the
weight of the boiler and the system piping, when full of water.
A. INSTALL THE WALL BRACKET. SEE FIGURE 1a.
1. Remove the wall bracket from the wood packing, by unfastening the
two screws that holds it in place, for shipping purposes only.
2. Select the location on the wall where the boiler will be mounted.
The upward facing tabs of the wall bracket will align with the top
surface of the boiler jacket.
3. For sheetrock and stud construction, locate the studs and
determine which set of holes in the wall bracket best align
with the center of the studs. For cement walls, determine a
location for the wall bracket to mount where the anchors will
be secure, devoid of seams or cracks.
4. Place the bracket in the selected location, with the 2 tabs
positioned up and facing outward, level it out, and mark the
holes to be used. A minimum of 4 of these holes must be
utilized, regardless of wall material.
5. Drill the appropriate diameter and depth holes for the
fasteners used in the wall, where marked.
6. Fasten the wall bracket to the wall, being sure that the tabs
face upward and outward, and the fasteners have engaged
the wall properly.
B. INSTALL THE BOILER ON THE WALL. SEE FIGURE 1.
1. Lift the boiler up against the wall, with the top edge of the jacket
slightly above the wall bracket tabs. Engage the boiler jacket near
top lip notches properly.
2. There are fastener holes in the lower area of the boiler rear
panel to ensure that the boiler does not move off the wall bracket.
Mark these 2 holes, with the boiler in place, then lift the boiler off
the wall bracket.
3. Determine which fastener type will best engage with the wall construction at the location of the 2 market holes. Drill out the appropriate diameter and depth holes for the fasteners, where marked.
4. Lift the boiler up onto the wall bracket again, as described in
Step 1. Secure the boiler to the wall, with the 2 fasteners in the
lower rear panel area.
PIPING
Air Separator and Expansion Tanks
The recommended piping arrangement is shown in Figures 2 through 4.
Note that there is a built-in air eliminator in the heat exchanger (air vent,
however, is by others). A 1/8" air vent may be used (bushing is needed
for 1/2" NPT tapping). Additional air vents should be installed at points
just upstream from all drops in elevation of the piping system (high
points).
Relief Valve Discharge Piping
Use same size or larger piping than valve outlet piping. Must terminate
152mm ( 6”) minimum from floor with a plain (no threads) end. Place a
bucket under pressure relief valve discharge piping. Make sure discharge is always visible. DO NOT hard-pipe to drain piping.
Flow Switch
A FLOW SWITCH MUST BE INSTALLED. It is intended to prevent the
burnout of heater elements should the circulator fail, or should air accumulate in the boiler due to faulty air elimination (see Table 2 for flow
switch size required). FLOW SWITCH MUST BE INSTALLED IN HORIZONTAL POSITION.
Bypass
The bypass shown must be set so that a sufficient amount of water can
circulate through the boiler when all zone valves are closed. See Figure 3.
Multi-zone Balancing
Raise all zone thermostat settings and verify that all zone valves are open
(not bypassed). Close all electrical panels. Turn on 10 amp control circuit
breaker ONLY. Pump should operate. Note the pressure reading on the
pump discharge. Lower each zone thermostat setting to close corresponding zone valve. Adjust the corresponding balancing valve to maintain
pump discharge pressure. The pump discharge pressure should remain
the same when all zones are in bypass or when all zones are open or any
combination of opened and closed. See Figure 4.
WIRING
To wire the electric boiler, perform the following procedures:
1. Wall Thermostat Flow Switch and Circulator
• All circuit breakers ahead of and at boiler must be OFF. Remove
the Control Panel (left-hand front) Cover by removing 5 screws
from top, bottom and side flanges.
• The right-hand compartment under the Control Panel Cover contains a terminal board marked, (SLANT/FIN “INTERFACE
BOARD”). Wire a 2-wire 24V room heating thermostat or the auxiliary end switch terminals of zone valves (see Figure 5) to terminals
3 and 4 at this time. The 1 and 2 terminals are for the flow switch.
The flow switch circuit is a low voltage circuit.
• Wire the circulator and connect 115V wires and conduit through
1/2" knockout. provided on bottom left hand corner, to the “INTERFACE BOARD” at terminals “L” and “N”, where it is marked “CIRC.
PUMP”.
2. Service Connections and Electrical Ratings
A. All circuit breakers ahead of and at boiler must be OFF.
Remove the Service Connection Panel (right hand front). Cover by
removing 5 screws from the top, bottom and side flanges (see
wiring diagram on back of the Service Connection Panel and
Figure 5).
B. Draw power feeder cable (75°C minimum) and conduit through
service knockout provided on top and bottom.
C.Connect hot lines to distribution block provided in service compart-
ment. A ground lead should be drawn and wired to the ground lug
in the service compartment. If rating plate indicates boiler is a single phase 3-wire or 3-phase 4-wire model, draw a neutral wire #12
AWG maximum, 75˚C. minimum and connect to neutral lug mount
provided in service compartment. See Tables 1 and 3 for lug sizes
and current ratings.
3. Wiring Control
• See EM-10 Electronic Control Set Up Instructions #790860000
for setting up control.
Page 3
EH-M3-40 Boiler Operation and Installation Instructions 3
Figure 1.
Figure 1a.
MINITRON "ROUGH-IN" DIMENSIONS
1. UNIT MAY BE FULLY ENCLOSED
IF CLEARANCE DIMENSIONS ARE
RESPECTED.
2. DUAL DIMENSIONS ARE: INCH [MM]
ø
1 3/4 [44]
WALL
TOP
VIEW
12 [305]
MINIMUM
(1/2" PLUG)
19 25/32
[503]
BOILER MUST BE LEVEL
4 5/32 [105]
1 7/8 [48]
2 19/32
[66]
ø
1 3/4 [44]
(3/4" RELIEF VALVE)
8 [203]
MINIMUM
STUDS
FACE TABS UP AND
FORWARD. INSTALL
TABS LEVEL.
SECURE WALL
BRACKET INTO STUDS
WITH APPROPRIATE FASTENERS
12 [305]
MINIMUM
8 3/32
[205]
WALL
2 19/32
[66]
15 17/32
[395]
16 [406]
MINIMUM
(REQUIRED FOR
REPLACING
ELEMENTS)
5 1/2 [139]
1
[25]
7/8 [22] KNOCKOUT
(110V CONDUIT FOR
CIRCULATOR OR
TRANSFORMER)
1 3/4 [44]
BOTTOM
VIEW
7/8 [22] KNOCKOUTS
(24V CONNECTIONS)
TYP
WALL
ø
2 3/16 [56]
(1 1/4" RETURN)
1 29/32 [48]
1 [25] TYP
16 [406]
ø
1 11/32 [35]
KNOCKOUT
3 [76]
14
[356]
3 1/2 [89]
1 1/2 [38]
DUAL KNOCKOUTS
ø
1 3/4 [44]
ø
1 1/8 [29]
6 9/32
[160]
2 19/32
[66]
2 25/32
[70]
ø
2 1/8 [54]
(1 1/4" SUPPLY)
RIGHT SIDE VIEW
BOILER HEIGHT ABOVE
WALL BRACKET TABS
WALL
1/4
[6]
Page 4
4 EH-M3-40 Boiler Operation and Installation Instructions
Table 1. Lug Sizes
Table 2. Flow Switch Size Selection
* Straight pipe upstream and downstream of flow switch.
Model No.
Flow Switch
McDonnell & Miller No.
Pipe
Size
Minimum
Pipe Length*
EH-8-M3 thru EH-20-M3 FS4-3T3-1 1" 6-1/2”
Distribution Block
Grounding Lug
Neutral Lug
Wire Size Wire Size Wire Size
Model Phase CU-AL† CU-AL† CU-AL†
EH-8 thru 20 1 6-2/0 6-2/0 6-2/0
EH-12 thru 20 3 6-2/0 6-2/0 6-2/0
Neutral Lug Wire Size:For 3-wire single phase and 4-wire 3 phase
models equipped with circuit breakers. The neutral tap is for the
circulator and control transformer.
† ALUMINUM conductors may be used, lug size, conduit size, ampacity and all
applicable codes permitting.
Table 3. Current Ratings
† Leg with the highest value of line current of an unbalanced 3-phase load.
‡ 125 VAC maximum rating of all hot conductors.
SINGLE PHASE 3 WIRE, 120/208V
‡
Basic Model
No.
Heater Amperes
@ 208V
EH8-13-8-M3
EH10-13-8-M3
EH12-13-8-M3
EH16-13-8-M3
EH20-13-8-M3
29
36
43.4
58
72
SINGLE PHASE 3 WIRE, 120/240V
‡
Basic Model
No.
Heater Amperes
@ 240V
EH8-13-4-M3
EH10-13-4-M3
EH12-13-4-M3
EH16-13-4-M3
EH20-13-4-M3
33
42
50
67
83
THREE PHASE 4 WIRE, 120/208V
WYE CIRCUIT ONLY
‡
Basic Model
No.
Heater Amperes †
@ 208V
–
–
EH12-34-8-M3
EH16-34-8-M3
EH20-34-8-M3
–
–
43
58
†
72
†
THREE PHASE 4 WIRE, 120/240V
DELTA CIRCUIT ONLY
‡
Basic Model
No.
Heater Amperes †
@ 240V
–
–
EH12-34-4-M3
EH16-34-4-M3
EH20-34-4-M3
–
–
50
67
†
83
†
Page 5
EH-M3-40 Boiler Operation and Installation Instructions 5
NOTES:
1. Optional blocking gate valve and hose end valve used (with drain valve) for fast fill and purge of system.
IMPORTANT: Close bypass line valve (if used) during purging.
2. Circulator should not be installed at lowest point of piping.
3. There should be no elbows, tees, or change of pipe size for at least 5 diameters of pipe size (see Table 2) upstream and downstream of flow switch.
Flow switch should always be mounted in the horizontal position. See Table 2.
Figure 2. Typical SIngle Zone Piping
Figure 3. Typical Multi-Zone Using 2-Way Valves
Figure 4. Typical Multi-Zone Using 3-Way Valves
Page 6
6 EH-M3-40 Boiler Operation and Installation Instructions
START-UP
NOTE: Make sure that all circuit breakers ahead of and at the
boiler are OFF.
Fill System
See Figures 2 through 4 for suggested purge valve and blocking
valve. If system is filled but not purged, radiators must be vented
individually, to prevent air blocking of water flow. Fill to approximately 12 psi (cold water), whether automatic or manual fill is
used. DO NOT apply full line pressure to system; boiler and
relief valve are rated at 30 or 50 psi (see rating plate). Suddenly
applied main pressure can exceed 100 psi.
Air Elimination
Diaphragm tank and air vent valve are recommended, see
Figures 2 through 4. Air remaining in system will vent from the
automatic vent valve during system operation. Valve cap must be
loose or removed to allow automatic venting. Open relief valve
briefly after filling to pressure, to make sure boiler is free of air.
Bypass flow adjustment (Figure 3)
Close bypass valve. Turn down all zone thermostats. Inspect all
zone valves to be sure all are closed. Put a jumper on thermostat terminals 3 and 4. Close ALL panels and turn on the 10
AMP control circuit breaker ONLY. Be certain that the flow
switch wires are not connected to the flow switch terminals
1 and 2 and the ends of the wires are taped. Be certain that a
jumperwire is between terminals 1 and 2. Connect the ohmmeter or other continuity tester across the flow switch common terminal and the terminal that is normally open during NO FLOW.
Slowly open bypass valve until continuity tester lights or ohmmeter kicks to zero: flow switch now has closed contacts, indicating
required minimum bypass flow rate when piping circuits are shut
off. Bypass valves should be locked at this position. Shut OFF
ALL circuit breakers ahead of and at boiler and open CONTROL
PANEL (left hand) FRONT COVER. Remove jumper on thermostat terminals 3 and 4. Remove flow switch jumper wire from
terminals 1 and 2. Connect flow switch wire to flow switch terminals 1 and 2. Connect zone valve end switches (in parallel) to
thermostat terminals 3 and 4. See Figure 5 and wiring diagram
on boiler. Replace CONTROL PANEL COVER.
Check for Proper Boiler and System Operation
To check for proper boiler and system operation, perform the
following procedure:
1. Turn up all room thermostats.
2. On boiler models with a multiple stage electronic control system (model number on rating plate contains an "M3"), there
will be a delay whose response time will depend on operating
mode and other settings.
3. Current may be checked by a qualified electrician at the feeder panel and compared to the values shown in Table 3.
4. Water flow through the boiler should be sufficient to keep the
flow switch closed. The limit thermostat should also remain
closed. Consult the multiple stage electronic control manual
for control setup.
OPERATION
IMPORTANT:
DO NOT operate boiler until the following criteria have
been met:
1. Must be installed by qualified heating and electrical
contractors in accordance with instructions in this
manual.
2. Must be installed in compliance with local codes.
3. Must be inspected and approved by installing contractors and any local authority having jurisdiction, and be
approved for operation by them.
• Ask the installer to explain operation of the entire heating
system.
• Turn on all circuit breakers for boiler and circulator.
• Adjust wall thermostat to required temperature. If room
temperature is lower than the thermostat setting, the first
heater stage will go on and the balance of the heater
stages will go on one at a time with a delay between
stages.
IMPORTANT
You must turn on the circuit breaker marked "10" in order to
operate the boiler control system. You then may turn on the
other circuit breakers (those marked 25, 30, 50 or 60).
PERIODIC INSPECTION
The hot water system, which includes the Minitron boiler, the
radiators and water control devices, should remain filled with
water at all times. DO NOT drain except to make repairs or to
prevent freeze-up during extended cold weather shutdown.
The pressure/temperature gauge on the Minitron should be
checked frequently: at the highest operating temperature,
pressure should be the same throughout the heating season.
If pressure (at a constant temperature) consistently rises or
falls over a period of time, a fill valve leak, a system leak or
compression tank malfunction is indicated. Leaks anywhere
in the system must be repaired without delay. Regular addition of fresh water to replenish leaks adds oxygen and lime.
Oxygen corrosion will cause further leaks and parts failure,
lime buildup on heating elements will cause element failure
due to overheating. If any leaks are found, or if pressure
changes, call for service immediately.
IMPORTANT
Under no circumstances should any electrical wiring or
internal controls be touched, except by an authorized
electrician (wiring and controls) or heating system service expert (system service, repair, shutdown). Any
mechanical adjustments to the heating equipment and
system must be made by a qualified heating
serviceperson.
Page 7
EH-M3-40 Boiler Operation and Installation Instructions 7
Figure 5. Electrical Connections
BTC
Mode 4
Relay
Outdoor
Sensor
Boiler Inlet Sensor (Included)
Factory
Installed
Boiler
Outlet
Sensor
BTC
Mode 5
Outdoor
Sensor
Relay
Factory
Installed
Boiler
Outlet
Sensor
Boiler Inlet Sensor (Optional)
Secondary
Piping
Sensor
(Included)
Figure 5A. Sensor Location
Boiler outlet
sensor factory
wired and
installed in
cast iron heat
exchanger
Figure 6. DHW Connections
Page 8
8 EH-M3-40 Boiler Operation and Installation Instructions
Basic Monitron II and Minitron M3 Setup
Field Entry Example for Mode 4 or Mode 5
Field Entry Low Temperature System Note
MODE 4 or 5 4 = Parallel Piping, 5 = Primary/Secondary Piping
STGMODE PID P P
BOIL TARGET 180 180 180 This is for DHW setpoint demand - if used
OUTDR START 70 70 70
OUTDR DSGN -10 -10 -10 May be -20 or -30F depending on area design temp.
BOIL START 70 70 70 This is used in the calculation of slope
BOIL DSGN 180 180 130 Radiant - 130 Wet, 140 or 150F for Dry system
BOIL OUT MAX 200 200 150 Default 200 - Use "FACTORY" Dip Switch to Adjust
BOIL MAX 170 170 130 Default 180 - Use "FACTORY" Dip Switch to Adjust
BOIL MIN 140 140 80 Default 140 - Use "FACTORY" Dip Switch to Adjust
DLY Not valid for Electric Boiler application
BOIL MASS 1 N/A N/A
STG DLY Au if PID in STGMODE N/A N/A Minimum time between firing stages
DIFF Au if PID in STGMODE 2 2 On or off of contact = 1/2 differential around target temp
STG DIFF 4 4 Temperature drop at which next stage turns on
ON DLY 1:00 1:00 Time before turning on next stage
OFF DLY 0:30 0:30 Time before turning off next stage
MIN ON 0:30 0:30 Minimum time stage is on before allowed to go off
MIN OFF 0:30 0:30 Minimum time stage is off before allowed to come on
PUMP DELAY Off Off Off
WWSD
0 F
Baseboard System
4 or 5
Can be set 10F over BOIL DSGN
Set same as BOIL DSGN
Note:Some heating equipment may require a
minimum water temperature - ie fan coils
no entry
65
F or C
Set the "MODE" to 1 or 2 if an outdoor Sensor is not used (1 = parallel piping, 2 = primary/secondary piping)
Caution:
"Factory" position on dip switch has to be returned to "Installer" position to prevent unauthorized changes to
Factory settings.
Page 9
EH-M3-40 Boiler Operation and Installation Instructions 9
Notes:
Page 10
10 EH-M3-40 Boiler Operation and Installation Instructions
Page 11
EH-M3-40 Boiler Operation and Installation Instructions 11
Page 12
SLANT/FIN CORPORATION, Greenvale, N.Y. 11548 • Phone: (516) 484-2600
FAX: (516) 484-5921 • Canada: Slant/Fin LT D/ LT EE , Mississauga, Ontario
www.slantfin.com
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