Low Water Cutoff; High Limit Safety Switch - Riello Array AR 3000 Installation And Operation Manual

INSTALLATION

2.7 Low water cutoff

A low water cut off (LWCO) is installed on each boiler.
To check the functionality of LWCO go to the 905PB inner display,
access the Settings menu, select Test mode, and then click on
LWCO1. On the screen will appear the error "MN: Low Water Cutoff
Error".
At this point press the reset button. The error will turn off.

2.8 High limit safety switch

A high limit safety switch is installed on each module of the boiler.
To simulate a high limit lockout at 208°F go to the 905PB inner
display, access the Settings menu, select Test mode, then click on
Max temp.
The control will display "MN: Max. Thermostat Lock Error".
At this point press the reset button on the removable display to
restart the module.
2.9 Pressure relief valve installation
ASME rated Pressure Relief Valves are factory installed in each Array
Boiler. The pressure rating for the relief valves is 75 PSI. The relief
valves are installed on each hot water horizontal manifold of the
boiler as shown in Fig. 8. The relief valves drain piping must be
connected to a nearby floor drain. In multiple unit installations
the discharge lines must not be manifolded together.
Each must be individually run to a suitable discharge location.
Relief valves should be manually operated at least once a year.
If a relief valve discharges periodically, this may be due to thermal
expansion in a closed water supply system.
Contact the water supplier or local plumbing inspector on how to
correct this situation.
Do not plug the relief valve.
Fig. 8 Pressure Relief Valve Location
2.10 Condensate drain and piping
The Array Boiler is designed to condense water vapor from the flue
products. Each module of the boiler is equipped with a conden-
sate trap (see Fig. 9), while a syphon collects the condensate of the
vertical flue manifold.
75PSI Relief valve
(one for each pair
of modules)
Fig. 9 Condensate Drain System
9
10
Condensate
Trap
Condensate
Trap
Condensate
Trap
Condensate
Trap
WARNING: At the Start-up and after prolonged shutdown of
the boiler, the condensate traps and the syphon must be filled
with water prior to restart it, otherwise combustion gases will
enter the room with a risk of an excessive level of carbon
monoxide.
Fill the syphon with
water from the top
of the vertical flue
manifold BEFORE
to connect the vent
piping
Vertical Flue
Manifold
Syphon