COMBOMAX
MC
Electric boiler Set-up, use and care guide
(revised Oct 2015)
, Page
6.
Insulate all pipes containing hot water,
especially in unheated areas.
Install shutoff (ball) valves for servicing
convenience. Install thermometers on the inlet
and outlet lines.
Never plug the pressure relief valve to avoid
creating a hazardous situation.
3.5.2 Flow-check valve
If the heating system uses a single circulator, a
flow-check valve must be installed to
minimize gravity flow and heat loss during non-
draw periods.
3.5.3 Pressure relief valve
No boiler set-up is complete without a pressure
relief valve. Its pressure rating must not exceed
30 psi (207 kPa). It must conform to the « ASME
Boiler and Pressure Vessel Code» and limit the
boiler operating pressure. It is a safety device,
not a control device.
The BTU per hour rating of the relief valve must
equal or exceed the BTU per hour input of the
boiler(s) or heat source(s) as marked on the
boiler(s) rating plate.
Connect the outlet of the relief valve to a
suitable open drain, with the discharge at most
6” above the floor, far from any live electrical
parts. The discharge line must pitch downward
from the valve to allow complete draining and be
no smaller than the outlet of the valve. The end
of the discharge line should not be threaded or
concealed and should be protected from
freezing. No valve of any type, restriction or
reducer coupling should be installed in the
discharge line. Local codes shall govern the
installation of relief valves.
3.5.4 Operating pressure control :
Operating pressure control components ensure
minimum and maximum operating limits within
the design operating temperature range of the
heating system.
Expansion tank
The purpose of the expansion tank is to absorb
the water volume increase of the boiler and the
heating system related to the variation of its
water temperature during the heating season.
Consequently, the selection of the appropriate
expansion tank model must be made taking into
account both the maximum operating
temperature of the system and its water content.
Note that the water content of an heating system
with cast iron radiators is a lot more than a
system with hot water baseboard.
The important increase of heating water volume
brought with the addition of the Combomax will
also have to take into account.
Combomax 23 : 30usgal.
Combomax 34 : 40usgal
Combomax 44 : 52usgal
Combomax 64 : 76usgal
With these informations, these informations, the
installer with his distributor shall be in position to
make an appropriate selection.
You will find below our recommendation on the
minimum size of tank in relation to the type of
heating system of the application.
Combomax #
Hot water
Baseboards
Radiant
floor
Cast iron
radiator
Combomax 23
#30
#30
#60
Combomax 34
#30
#30
#60
Combomax 44
#30
#30
#60
Combomax 64
#60
#60
#90
The expansion tank connection point must be
carefully chosen to prevent a situation where
closing a valve would isolate the tank from the
boiler or any part of the circuit.
3.5.5 Makeup valve
Connecting a makeup valve must be done
according to code. This valve must include a
flow-check valve to maintain the minimum
operating pressure by admitting fresh water from
the cold water supply line in case a leak occurs.
3.5.6 Air bleeder
There should be as little oxygen as possible in
the heating circuit to prevent corrosion. As
foreseen in section 3.5.4, this excludes the use
of air as a pressure regulator within the circuit.
Installing manual or automatic air bleeders
prevents air accumulation within the system.
The bleeders must be set at the highest points
of the system to purge any air accumulated
during system set-up and to check its air
tightness. Bleed the air regularly from the piping,
making sure the heating water causes no bodily
harm or material damage.
