VOLTMAX ELECTRIC BOILER Installation and Operation Manual
(
Revised March 2019)
, Page
11.
be protected from freezing. No valves, valves or
valves shall be installed on the pipe. The
installation of the safety valves is governed by the
local code.
SYSTEM PRESSURE CONTROL
AND EXPANSION TANK
Pressure control devices within the system ensure
that each component operates within minimum
and maximum allowable pressures and maintain
minimum pressure for all normal operating
temperatures. They also allow air bleeding,
prevent cavitation at the pump inlet and prevent
water from boiling within the system; all this is
accomplished with minimal addition of new water.
The increase in boiler water volume resulting from
higher temperature is stored in the expansion tank
during periods of high operating temperature and
is returned to the system when the temperature
decreases.
The expansion tank must be able to store the
required volume of boiler water during maximum
design operating temperature without exceeding
the maximum allowable operating pressure, and to
maintain the required minimum pressure when the
system is cold. Contact your installing contractor,
plumbing supply house, or local plumbing
inspector for assistance. The point where the
expansion tank is connected should be carefully
selected to avoid the possibility that normal
operation of automatic check or manual valves will
isolate the tank from a hot boiler or any part of the
system.
The expansion tank should preferably be located
on the suction or intake side of the pump.
WATER PRESSURE MAKEUP
REGULATOR
Make-up systems must be employed as required
by codes. An automatic fill valve (automatic
pressure regulator) must be used with a backflow
preventer as required, to maintain minimum
system pressure by supplying water to make up for
leakage.
A minimum pressure of 5psi (34kPa) must be
maintained at all times.
A backflow prevention device that complies with
local standards must be installed upstream of the
pressure regulator.
AIR BLEEDER
The air contained in the heated water must be
removed from the system to allow the proper
functioning of the heating system and the boiler.
Installation of manual or automatic air vents is
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 ensure that all air
possibly located in the boiler be eliminated at all
time.
Regularly purge air from the pipes and beware that
the heated water does not cause injury or damage.
If the boiler is located at a location higher than the
heat distribution system such as a heated floor, an
automatic air eliminator should be installed close
to the boiler outlet.
CIRCULATING PUMP
The pump capacity required is determined in
relation to the capacity of the boiler installed and
the type of heating distribution system on which it
will be connected.
They are generally designed for an operation at a
differential of temperature (Delta T0) of 10 to 20F
between the supplies and return temperature to
the boiler.
Use the following equation to determine the
required water flow.
Pump flow rate = Boiler power ÷ Delta T ÷ 500
•
Pump flow rate is expressed in US gallons per
minute or GPM.
•
The Boiler output (in net BTU per hour) is the
maximum amount of heat to be transferred
through the heating loop to meet the heating
load.
•
Delta T: The boiler water temperature drop
For example, an electric boiler rated at 180KW has
an output capacity of 614 160 BTU per hour. The
system is designed for a temperature drop of 20°F.
Required pump flow rate = 614,160
20
500 =
61,4 GPM
