13
SEQ-3 Digi-Elite Operation Manual
Domestic Hot Water (DHW) Priority
Options:
NO and From 1 min to 120 min
Default: NO
SET
SET
/Settings>/DHW Prior.
DHW Priority:
60m
• The DHW Priority, with a value set to other than NO, provides the user with an adjustable DHW priority timer for the domestic
hot water call. That is, initiating a DHW call will de-energize the system pump relay for the period set by the DHW Priority.
However, the DHW relay, when 1-On/Off+2-Pump is selected as the Output mode from the Startup menu, will remain energized
for as long as the DHW is active. This will take place whenever the Outdoor temperature is below Outdoor Cutoff and the EXT+/
EXT- (Enable/Disable terminals) are closed/shorted.
• On the other hand, when the EXT+/EXT- (Enable/Disable terminals) are open or the Outdoor temperature is 2°F above the
Outdoor Cutoff, a DHW priority call will energize the DHW pump and boiler relays. When the DHW call expires, the DHW
Pump relay will remain energized for the Run-On delay then de-energize.
• If NO was selected as the option for the DHW Priority, a DHW call will energize both relays, system pump and DHW pump even
when TSTAT is de-activated.
Setback
Options:
From 0
º
F/0
ºC
to 80
º
F/44
ºC
Default: 10
º
F/6
ºC
SET
SET
/Settings>/Setback.
• The Setback feature can be used to provide the SEQ-3 with a lower temperature Set Point when
less heat is required by closing the P+ and P- terminals.
• The lower Set Point will appear on the main display indicating
SBC TGT=
.
Setback:
20 F
SYSTEM=
68 F
SBC TGT=
140 F
• For example; when the calculated temperature is 160°F and the Setback is set to 20°F, a setback
call will change the Set Point to (160°F - 20°F) 140°F.
• A typical use for the Setback is to provide a reduced system temperature to a building during the
night or on the weekends when building is not occupied, but heat is still required.
• The Setback is activated by closing/shorting the P+ and P- terminals using an external timer,
control, or a switch.
Boost
Options:
Yes, No
Default: No
SET
SET
/Settings>/Setback/Boost.
• The morning Boost is designed to return the building to comfortable ambient temperatures
after the night Setback period. The SEQ-3 will accomplish this by running elevated water
temperatures (will add Setback setting to calculated water temperature) for 30 minutes after
the opening of the setback terminals P+ and P-. That is, if the normal set point at a specific
outdoor was 145˚F and the Setback setting was 20˚F, the boost will raise the system calculated
temperature to 165˚F for 30 minutes after the setback.
Boost:
No
Yes
System and Outdoor Trim
Options:
From -20F
º
/-11
Cº
to +20F
º
/+11
Cº
Default: 0F
º
/0
Cº
SET
SET
/<Maintenance>/Sys. Trm or Out. Trim
• The Heat-Timer sensors are very accurate. However, sometime it might be beneficial to adjust
the values to match and existing system. The System and Outdoor Trim values adjust the System
Sensor and Outdoor Sensor readings using positive or negative values.
System Trim:
+0 F
Outdoor Trim:
+0 F
Enable/Disable (TSTAT) Input
• The SEQ-3 will provide heat only if the EXT- and EXT+ terminals are shorted. If no external
equipment or switch is connected to these terminals, leave the factory jumper
installed.
•
When the terminals are OPEN, the Target will display
TSTAT OPEN
.
•
Even if the EXT terminals are open, a call for DHW will energize the output relays based on the
DHW Priority configuration.
•
The Enable /Disable terminals can be used as a Summer/Winter switch when connected to an
external switch.
T2
T3+
COM
T3- EXT+ EXT- P+ P- COM 24V
Enable/Disable
Wiring
NOTE:
On a sensor fault while the Enable/Disable terminals are open, the control will follow the
Enable /Disable state regardless of the sensor fault condition.
SYSTEM=
55 F
TSTAT OPEN
SYSTEM=
SHORT
TSTAT OPEN