Laars Rheos RHCH, Installation And Operation Instructions Manual, Page: 19 / 60

Rheos Boiler and Water Heater
Page 19
Increase the head loss requirement by 20%.
IMPORTANT NOTES : Different glycol products
may provide varying degrees of protection. Glycol
products must be maintained properly in a heating
system, or they may become ineffective. Consult the
glycol specifications, or the glycol manufacturer, for
information about specific products, maintenance
of solutions, and set up according to your particular
conditions.
SECTION 4B.
Water Connections —
Rheos Water Heater
4B.1 Water System Piping —
Water Heater
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.
The Rheos can be used with several different
types of readily available storage tanks. A pump draws
water from the storage tank and pumps the water
through the heater and back into the tank. Pump-
mounted units have a circulating pump built into the
water heater.
Pipe the outlet from the heater’s relief valve
such that any discharge from the relief valve will be
conducted to a suitable place for disposal when relief
occurs. Do not reduce line size or install any valves in
this line. The line must be installed to allow complete
drainage of both the valve and the line.
Suggested piping diagrams are shown in Figures
9, 10, 11 and 12. These diagrams are meant only as a
guide. Components required by local codes must be
properly installed.
The minimum inlet water temperature for the
Rheos is 130°F (54°C) to avoid condensing on the
copper coils.
4B.2 Hot Water Supply Piping —
Water Heater
Follow the tank manufacturer’s guidelines for
completion of the hot water system connections.
feet (9.1m) of full-sized piping and a normal number
of fittings.
Table 8 specifies water flow rates for boilers,
which will enable the user to size a pump. The
headloss shown is for the heater only, and the user
will need to add the headloss of the system piping to
properly size the pump.
The minimum inlet water temperature for the
Rheos is 130°F (54°C) to avoid condensing on the
copper coils.
4A.4 Freeze Protection – Boiler
Proper precautions for freeze protection are
recommended for boiler installations in areas where
the danger of freezing exists.
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.
Do not use automotive anti-freeze. Maintaining
a mixture of minimum 50% water and maximum
50% properly inhibited HVAC glycol, which contains
an antifoamant, is the preferred method of freeze
protection for Rheos boilers. Percentage of glycol
used in the Rheos boiler must not exceed 50%.
Typically, this mixture will serve as burst protection
for temperatures down to approximately –35°F (-
30°C). To get the desired temperature rise across the
boiler when this mixture is used, increase the water
flow by 15% above the original recommendation.
Connector
Module
Dial
Setpoint Adjustment
Differential
Adjustment
Energized
Relay
LED Indicator
Relay
VDC
COM
24V
SEN
Jumper Block
Position
Heating
Cooling
Note: Jumper must
be in “Heating” mode,
or Rheos will not
operate properly.
Figure 13. Temperature Control.