08/07/2008 2
BI301D
If the zoning system is more complex and you need a zone controller shown on the accessories sheet, select the
appropriate model and when ordering specify Mini-Boiler application.
AVAILABLE, ELECTRO INDUSTRIES, INSTALL PARTS OR KITS
EMB-BK
MINI-BOILER PLUMBING KIT BASIC
EMB-P2
PUMP KIT 1/25HP BOILER
ES-24-SRO STAT
DIG
SLAB/ROOM/ROOM 24VAC
5616
TRANSFORMER HTR 4X4 PLATE 40VA 24VAC
5576
AIR ELIMINATOR 3/4" ROLLAIRTROL
5456A
GAUGE PRES/TEMP 75 PSI/320DG F .25"
5453
VALVE RELIEF 30 PSIG .75” NPT MALE
5590
EXPANSION TANK 40K BTU 2.1 GAL.
EMB-PK
MINI-BOILER INSTALL KIT PREFERRED
EB-5415A ZONE
CONTROLLER
OPTIONAL AQUASTAT, TYPICAL STRAP-ON
If zones or reduced radiation require an external temperature control device to prevent boiler hi-limiting, there are
two recommended electrical connections.
•
Two unbalanced zones, ½ of the 9 kW will carry the smallest zones
– in this case use the aquastat
to “stage” the boiler or remove the second element when the temperature rises. Reference hookup
diagram (BH302 P.1) note 5. Remove white/blue jumper and install an open with temperature rise
aquastat contact in place of this jumper.
•
Two unbalanced zones, smallest zone requires less than ½ of the boiler capacity
– in this case the
temperature controlling aquastat must turn off both elements. Cut one of the red/white wires going to
the 160° F (71° C) screw-in hi-limit and electrically insert an open with temperature rise aquastat
switch contact. Set the aquastat below the 160° F (71° C) limit value which allows the aquastat to turn
off both elements.
•
Note
: Aquastat setting – suggest aquastat settings be approximately 5° F (2.7° C) higher than designed
outlet temperature for the system.
•
Other options
– request procedure BD002.
TEMPERATURE CONTROL
The limits or temperature sensing components within this unit are for safety purposes only. The system installation
must have a proper responding slab sensing thermostat (or zone controlling device) to properly turn the boiler on
and off. If the water flow is greater than the minimum GPM (L/min) specified, this boiler should not reach hi-limit
and the hydronics loop should continue to flow in the normal heating pattern until the operating thermostat is
satisfied. If hi-limiting is experienced prior to satisfying the operating thermostat, there is possibly a water flow
problem.
INFORMATION/WATER FLOW CALCULATIONS
Water flow, GPM (L/min), can easily be calculated if the temperature rise across the electric boiler can be
measured.
The formulas below can only be used when the temperature rise is stable and the boiler is not hi-limiting. In other
words, verify constant current draw and stable outlet temperatures for at least 15 minutes.
Volts x Amps x 3.4
240 volts x 36 amps x 3.4
29376
GPM=
500 x Temp. rise ° F
Example:
500 x 12° F rise
=
6000
= 4.9
gpm
INFORMATION/WATER FLOW CALCULATIONS – METRIC
Volts x Amps x 3.587
240 volts x 36 amps x 3.587
30991.68
L/min =
251.04 x Temp. rise ° C
Example:
251.04 x 6° C rise
=
1506.24
= 20.57
L/min
