LAARS Rheos+ RHHV - Install and Operating Manual - Manual (Page 42)

Rheos+ Boiler and Water Heater Page 41
shutoff valve. Remove the front and right-side panels
from the unit. Disconnect the union between the valve
body and the blower. Label the four pressure tubes
that are connected to the valve actuator, to ensure
that they will be replaced correctly. Remove the
valve actuator, per the instructions above. Unscrew
the valve body from the gas train. After the valve has
been removed, replace with a new valve in the reverse
order. Turn on gas shutoff valve and 120 volt power
and check appliance operation and tightness of gas
valve connections.
7.2.4 Safety Gas Valve
The safety gas valve is a 24-volt diaphragm
valve. It is designed to operate with supply pressures
of 4-13 inches w.c. (1.0 to 3.2 kPa). To remove the gas
valve, shut off 120-volt power. Shut off the main gas
supply to the unit. Disconnect the gas supply piping
from the back of the unit. Disconnect the electrical
wires from the valve, and unscrew the gas valve from
the gas train. Re-assemble in reverse order. A bleed
line from the diaphragm type automatic valve shall be
vented per local code requirements.
7.2.5 Manual Reset High Limit Control
The high limit switch is manual reset switch with
an adjustable set point, up to 240°F (116°C) on boiler
models and 200°F (93°C) water heater models. To
replace the switch, shut off the 120-volt power to the
appliance. Remove the cover from the switch to access
the mounting screws. Remove the screws, and pull the
switch off the control panel. Replace in reverse order.
7.2.6 Temperature Control
The temperature control consists of an adjustable
electronic control and digital display module. To
replace the control or the display, shut off the 120-
volt power to the appliance. Remove the cover from
the control panel, and remove the screws from the
DIN rail clip, to which the controls are mounted. Pull
the electrical connector from the controller. Slide the
controllers from the DIN rail clip. Replace in reverse
order.
7.2.7 Auto Reset Temperature Limit
The auto reset temperature limit has a 200°F
(93°C) setting. The is mounted directly onto the
Rheos+ header, on the inlet to the copper coil. It
senses the inlet water temperature to copper coil, and
guards against a malfunctioning mixing system. To
replace the switch, shut off the 120-volt power to the
appliance. Remove the cover from the switch to access
the mounting screws. Remove the screws, and pull the
switch off the control panel. Replace in reverse order.
7.2.8 Mixing Control
The FX05 mixing control is the device that
controls the position of the mixing valve system. This
control is factory set, and must not be adjusted, except
for the °F or °C choice. To remove the control, unplug
the wires from the back, push on the tabs to slide the
clasping mechanism off, and pull the controller out
through the front of the panel. Replace in reverse order.
7.2.9 Mixing Valves
There are two 2-way mixing valves that are
linked and connected to a valve actuator to create the
3-way mixing system. To remove the upper right
valve, remove the actuator and then remove the 2 bolts
that connect the sheet metal to the valve. Remove the
linkage from the arm that is welded to the actuator.
Remove the four bolts on the valve, and slide the
valve out. To remove the lower left valve, remove
the 2 bolts that connect the sheet metal to the valve.
Remove the linkage from the arm that is welded to the
actuator. Remove the four bolts on the valve, and slide
the valve out. Reassemble in reverse order.
Figure 29 - Control Panel