BTH Electric Boilers USE & CARE MANUAL
(Revision June.2014)
, Page
6.
manually maintain a minimum pressure when
required. Another possibility is to install a
pressurized storage tank specially made for those
applications that will inject on request an
appropriate quantity of liquid to maintain an
appropriate pressure on the heating system.
Air bleeder
Installation of manual or automatic air vents are
required to eliminate all air from the boiler and the
heating distribution system.
When the boiler is installed above the heating
distribution
system,
an
automatic
air
separator/eliminator must absolutely be installed
at the outlet of the boiler in order to eliminate all
possibilities of air buildup inside the boiler that
would damage the heating elements.
Circulating pump
We recommend that the pump be installed at the
outlet of the boiler with isolating valves as shown
in figure 3.
The pump shall be selected such as to be able to
supply adequate flow in relation to the heating
distribution system on which it will be connected
and the heating capacity of the boiler installed.
The table below will give you details on required
water flow for distribution systems having to
operate with a differential temperature of 10F and
20F between their inlet and outlet
.
Model
Diff. 10F (usgpm) Diff. 20F (usgpm) Boilerpress.drop
MINI Ultra 6
4.0
2.0
Negligible
MINI Ultra 7.5
5.1
2.5
Negligible
MINI Ultra 9
6.0
3.0
Negligible
MINI Ultra 12
8.2
4.1
Negligible
The boiler has to be activated only upon a call for
heat and when a pump will be working (no jumper
allowed on TT terminals) a minimum water flow of
1usgpm is recommended.
Your heating wholesaler shall be in good position
to recommend the appropriate model for your
application.
The amperage drawn by the pump and other
120volts components shall not exceed 5 amps or
1/6HP.
Drain valve
Installed at the lowest point of the unit, it allows
the unit to be drained for the eventual
replacement of a defective component.
Strainer
This component is used to collect potential
sediments coming from the distribution system
and more particularly from systems made of steel
piping
and
radiators.
If
such
sediments
accumulate at the bottom of the boiler it could be
harmful to the heat transfer of the elements and
generate premature failures.
ELECTRICAL CONNECTIONS:
Main boiler supply
Wiring must conform to the National Electrical
Code and to state or local code requirements.
The electric boiler must be electrically grounded in
accordance with local codes, or, in the absence of
local codes, with the National Electrical Code.
Wiring must come from a 120/240 Volt (single
phase, 60 Hz) “L1-L2-N” circuit protected by a
properly sized breaker.
Wire gage (3 wires+ground) must be properly
sized. Consult the boiler rating plate to select the
proper breaker and wire gage.
The main terminal block of the boiler is suitable for
#14 to #2 wires.
Supply cables can be made of Aluminum or
Copper and be rated for 90C (194F).
If aluminum cables are used, it shall be of an
adequate size (generally bigger) to meet the
National electrical code.
Electrical supply of External accessories
The total 120vac consumption of the boiler and
external accessories must not exceed 5A.
The maximum electrical consumption of 24vac
external accessories connected to R&C terminals
must not exceed 30Va. The available voltage at
the boiler transformer must not drop below 24Vac.
Outdoor temperature sensor
If you want the target boiler temperature to
modulate according to the outdoor temperature (
when the outdoor temp. will get colder, the target
temp. will get higher) , the supplied outdoor
sensor will have to be connected to S1 S1 before
turning the power on to the unit.
The installation of this sensor avoids the operation
of the boiler when the outdoor temperature
exceeds the selected value corresponding to the
maximum temperature required for heating.
The sensor shall be connected to terminals S1-S1
in the boiler using a two conductor cable 18ga.
