LAARS Heating Systems
Page 16
NOTE
: The Mighty Therm2 appliance and all other
gas appliances sharing the gas supply line must
be firing at maximum capacity to properly measure
the inlet supply pressure. The pressure can be
measured at the supply pressure port on the gas
valve. Low gas pressure could be an indication of
an undersized gas meter, undersized gas supply
lines and/or an obstructed gas supply line.
SECTION 4A.
Water Connections —
Mighty Therm2 Boiler
4A.1 Heating System Piping:
Hot Supply Connections — Boiler
NOTE:
This appliance must be installed in a closed
pressure system with a minimum of 12 psig (82.7
kPa) static pressure at the boiler.
Hot water piping should be supported by suitable
hangers or floor stands. Do not support piping with
this appliance. Due to expansion and contraction of
copper pipe, consideration should be given to the type
of hangers used. Rigid hangers may transmit noise
through the system resulting from the piping sliding in
the hangers. It is recommended that padding be used
when rigid hangers are installed. Maintain 1" clearance
to combustibles for hot water pipes.
Pipe the discharge of the relief valve (full size)
to a drain or in a manner to prevent injury in the event
of pressure relief. Install an air purger, an air vent,
a diaphragm-type expansion tank, and a hydronic
flow check in the system supply loop. Minimum fill
pressure must be 12 psig (82.7 kPa). Install shutoff
valves where required by code.
Suggested piping diagrams are shown in
Figures
4, 5, 6, 7 and 8.
These diagrams are meant only as a
guide. Components required by local codes must be
properly installed.
4A.2 Cold Water Make-Up — Boiler
1. Connect the cold water supply to the inlet
connection of an automatic fill valve.
2. Install a suitable back flow preventer between the
automatic fill valve and the cold water supply.
3. Install shut off valves where required.
NOTE:
The boiler, when used in connection with a
refrigeration system, must be installed so the chilled
medium is piped in parallel with the boiler with
appropriate valves to prevent the chilled medium
from entering the boiler.
The boiler piping system of a hot water heating
boiler connected to heating coils located in air
handling appliances where they may be exposed to
refrigerated air circulation must be equipped with flow
control valves or other automatic means to prevent
gravity circulation of the boiler water during the
cooling cycle.
A boiler installed above radiation level, or as
required by the authority having jurisdiction, must be
provided with a low water cutoff device either as a part
of the boiler or at the time of boiler installation.
4A.3 Water Flow Requirements — Boiler
A hydronic heating (closed loop) application
recirculates the same fluid in the piping system. As a
result, no new minerals or oxygen are introduced into
the system. To ensure a proper operating temperature
leading to long boiler life, a flow rate has been
established based on the fluid temperature rise for this
specific size boiler.
Pump-mounted boilers can be ordered for use in
primary secondary piping systems. The pumps used
are sized for the head loss through the heater, plus 30
feet (9.1 m) of full-sized piping (same size as boiler
outlet) and a normal number of fittings.
Table 8
specifies water flow rates for boilers,
which will enable the user to size a pump. The head
loss shown is for the heater only, and the user will
need to add the head loss of the system piping to
properly size the pump.
The minimum inlet water temperature for the
Mighty Therm2 is 120°F (49°C) to avoid condensing
on the copper coils.
4A.4 Freeze Protection — Boiler
Boiler installations are not recommended in
areas where the danger of freezing exists unless proper
precautions are made for freeze protection. A non
toxic, heating system, anti-freeze may be added to
the hydronic system provided that the concentration
does not exceed 50% and the anti freeze contains an
anti foamant. When a 50/50 mixture is used, increase
the water flow requirements by 15%, and increase the
head loss requirements by 20%.
Power outage, interruption of gas supply, failure
of system components, activation of safety devices,
etc., may prevent a boiler from firing.
Any time a
boiler is subjected to freezing conditions, and the
boiler is not able to fire, and/or the water is not able
to circulate, there is a risk of freezing in the boiler
or in the pipes in the system.
When water freezes,
it expands. This can result in bursting of pipes in the
system, or damage to the boiler, which could result in
leaking or flooding conditions.
