heat-timer DiGi-SPAN Elite Series Installation And Operation Instruction Manual

INSTALLATION AND OPERATION INSTRUCTIONS
Residential Snow Melt Control
Under Slab Snow-Melting Hydronic Heating System
2 Line Alphanumeric Display
Displays sensor values and
menu settings
®
SYSTEM =
RETURN =
SYS
Close Boiler Open
Pump
SET
Display Section Locking Screws
This Heat-Timer control is strictly an operating control;
it should never be used as a primary limit or safety
control. All equipment must have its own certified
limit and safety controls required by local codes. The
installer must verify proper operation and correct any
safety problems prior to the installation of this Heat-
Timer control.
RSM DIGI-E
Black (120VAC power)
Output Lights indicate
output status
o
147 F
o
125 F
DHW
System
Pump
R
C O R P O R A T I O N
WARNINg
®
The RSM-Elite is designed to control under slab heating
systems to prevent accumulations of ice or snow. To do
this, it monitors three temperatures, the outside temperature,
the temperature of the fluid going to the slab, and the
temperature of the fluid returning from the slab.
The slab must be kept above freezing (32°F) whenever there
could be frozen precipitation. Consequently, any ice or snow
which falls on the slab will melt immediately. If precipitation is
allowed to accumulate before the slab is heated, an effect called
bridging can occur. The snow or ice directly in contact with
Yellow
the slab will melt. But, the snow above will act as an insulator,
(System Pump)
reflecting the heat back into the slab. The slab itself will have
no ice touching its surface, but the remaining accumulation
will melt very slowly. To prevent this, the RSM-Elite activates
the slab heating system whenever the outside temperature
Red
falls below the adjustable outdoor cutoff temperature.
(Valve Common)
Once the slab heating system is activated, the amount of energy
White
entering the slab is determined by the difference between the
(Valve Open)
temperature of the fluid going to the slab (the Slab Supply)
and the temperature of the fluid returning from the slab (the
Blue
(Valve Close)
Slab Return). The difference between these two is called the
Slab ΔT or Delta T. The Slab ΔT will be different for each
slab composition based on the slab design. The higher the
Slab ΔT, the more energy is being input to the slab. If the
Slab ΔT is set larger than its design ΔT, the slab itself may
be damaged. The RSM-Elite provides a maximum Slab ΔT
adjustment which can be set from 5°F to 50°F. This setting
protects the slab during the initial warm-up periods.
After the warm-up period, each slab has a heat loss that varies
with the outdoor temperature changes. Thus, a slab might
require 130°F fluid temperature at 0°F outdoor temperature
to maintain its heat. However, when the outdoor warms to
15°F, it might require only 100°F fluid temperature circulating.
The RSM-Elite is provided with a Curve adjustment
to insure the slab temperature will be sufficient to melt
frozen precipitation once the warm-up period has ended.
lItE