BTH ULTRA Electric Boilers
Installation & Operation manual (Revision: June 2015)
11
3.4.2 Boiler piping connection
Make sure you connect the accessories and the
piping to the proper connection fittings as
indicated at figure 2 above and according to the
selected mounting position. The outlet and inlet
boiler connections are located on each sides.
They consist of 4
steel couplings (1”NPTF on 12 to
24kW models and 1-
1/4”NPTF on 27 to 36kW)
where the piping connection will be made.
Local codes may dictate the type of pipe to be
used for the connections.
Install isolating valves to facilitate maintenance
3.4.3 Pressure relief valve
This component is supplied with the unit and must
be installed on the boiler. It is designed to
automatically open at approximately 30 psi.to the
appropriate connection according to the mounting
position.
Connect the outlet of the relief valve downward to
a safe location in case of discharge.
The piping diameter used for the discharge piping
shall not be smaller than that of the valve outlet.
No valve of any type, restriction or reducer
coupling should be installed on the discharge line.
Local codes shall govern the installation of relief
valves.
3.4.4 Expansion tank
The expansion tank must be able to store the
increase volume of boiler water occurring when
the boiler water increase in temperature.. The
maximum allowable operating pressure is 30 psi
(207 kPa). Contact your plumbing supply house
for assistance.
3.4.5 Water pressure regulator
The boiler should be installed in such a way that it
can automatically be fed with water in the event of
a pressure drop.
The minimum pressure obtained when the system
is cold is generally 12 psi (83 kPa).
This accessory shall be equipped with one or
more check valves to avoid all possibilities of the
boiler water returning to the potable water supply
network (local regulation should be applied)
3.4.6 Air eliminator
Installation of manual or automatic air vents are
required to eliminate all air from the boiler and the
heating distribution system.
The main air eliminator must be installed near the
outlet of the boiler on the highest point of the main
supply piping. It is imperative to insure that all air
possibly located in the boiler be eliminated at all
time.
3.4.7 Circulating pump
Water flow is required at all time when the boiler is
operating.
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.
Table below shows required flow in relation to the
power capacity of the boiler and the required
temperature drop in the heating distribution
system. On System with baseboard heaters, 20°F
temperature drop is normally recommended and
on radiant floor application a value of 10°F is
generally used.
Table 5: Temperature rise vs flow rate
(GPM)
Model
KW
Diff. Temp.
Diff. Temp.
10
o
F
20
o
F
BTH ULTRA 12
12
8,2
4,1
BTH ULTRA 15
15
10,2
5,1
BTH ULTRA 18
18
12,3
6,1
BTH ULTRA 20
20
13,7
6,8
BTH ULTRA 24
24
16,4
8,2
BTH ULTRA 27
27
18,4
9,2
BTH ULTRA 29
29
20,5
10,2
BTH ULTRA 33
33
22,5
11,3
BTH ULTRA 36
36
24,7
12,3
Your heating wholesaler shall be in good position
to recommend the appropriate model for your
application.
If the pump is supplied by the PP terminals of the
boiler, its amperage plus the amperage drawn by
other 120V external components must not exceed
5A.
3.4.8 Drain valve
Installed at the lowest part of the unit, it allows the
boiler to be drained if defective components need
to be replaced.
3.4.9 Strainer
This component could be required on old heating
distribution systems made of steel or cast iron that
could carry sediments and sludge. 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.
