tekmar 269 One Stage Steam Control - Manual (Page 9)

Copyright © D 269 - 06/00 9 of 12
Indicator lights
There are ten LEDs on the front of the control that will aid in testing and troubleshooting. During normal operation, these lights
indicate the following functions:
Power light on • the 120 Vac power supply has been connected and the control is energized.
WWSD light on • the control has calculated that the outdoor temperature is warm enough to not require heat.
Unoccupied light on • the control is in the Unoccupied (setback) mode.
Steam Established • the condensate temperature is hotter than the setting of the Steam Established dial.
Heating Cycle • the system is operating in a normal Heating Cycle.
Early Start light on • the control is in transition into or out of the Unoccupied (setback) mode.
Boiler light on • the Boiler relay is on, closing the contacts between the Boiler (7 and 8) terminals.
Warning • the Warning relay is on, closing the contacts between the Warn. (3 and 4) terminals.
Auxiliary light on • the Auxiliary relay is on, closing the contacts between Aux. (5 and 6) terminals.
Test light on • the control is going through the Test routine.
Man. Override dial
When testing the operation of the control or setting up the system, the "Man. Override" dial can be set to a
fixed % On Time. When this dial is turned up from the
Auto position, the only other dial setting that has any
effect on the control operation will be the "Cycle Length" dial. Reset operation will resume when the dial is
turned all the way back down to the
Auto position.
Design Out dial
This dial is to be set to the design outdoor temperature of the heating system. A heating system should have
originally been designed and sized to meet the heating requirements of the building on all but the very coldest
of days. Unfortunately, in many older systems the calculations used to come up with a design outdoor
temperature (if any were actually done) were based on either sheer fantasy or on mathematical principles
long since lost to science. Once again, the installer may have to use trial and error to find this number. If the
building starts to become cold as the outdoor temperature gets colder, the dial should be turned up, and if
it becomes too hot as the outdoor temperature gets colder, the dial should be turned down.
Steam Established dial
When a Condensate Return Sensor is installed, the control monitors the sensor temperature and will keep
the Heating Cycle from starting until the sensor temperature rises to the temperature of the "Steam
Established" dial. To set this dial, turn off power to the 269 and allow the boiler to cool off if it has been running.
Set the "Steam Established" dial up to 230
°F and power the control back up. The control will operate the boiler,
making the system temperature rise as it tries to establish steam. Monitor the temperature of the Condensate
Return Sensor (for sensor placement see
Condensate Return Sensor Function, page 4), until the system has
come up to operating temperature. Reduce the setting on the "Steam Established" dial until the "Steam
Established" light comes on. If the Steam Established dial is set too low, system efficiency will suffer and
uneven heating will result as the boiler shuts down before heat reaches all of the radiators. If the dial is set
too high, the building will overheat during the milder weather unless an Indoor Sensor 074 is connected.
Auto
45%
100
0
Man. Override
Design Out
-40
0 °F
40
Steam
Established
180 °F
130 230
Testing the Control Functions
Min. On Time (%)
Lockout Diff'l ( °F)
Off
25
50
5
To calculate Lockout Diff'l (
°
F)
If: Steam Established dial = 170
°
F
System cool down temp. = 140
°
F
170 – 140 = 30
°
F Lockout Diff'l
x 100 = 17% Min. on time
5
30
To calculate Min. on time %
If: cycle = 30 minutes
Min on time = 5 minutes
Min. On Time (%)
Lockout Diff'l ( °F)
Off
25
50
5
Early Start Condensate Return Sensor
Indoor Sensor S2
Indoor Sensor S1
1 2 3 4
Off
Early Start Condensate Return Sensor
Indoor Sensor S2
Indoor Sensor S1
1 2 3 4
Off
Min. On Time (%) — Lockout Diff'l ( °F) dial
Without Condensate Return Sensor, this dial = Min. On Time (%)
When there is no Condensate Sensor installed to the control, this dial sets the minimum on time
for the boiler each heating cycle. The "Condensate Return Sensor" DIP switch must be in the off
position or an error message will occur. To set this dial, allow the boiler to cool off if it has been
running, and set the control on Manual Override with the maximum % On Time and maximum Cycle
Length. Locate the radiator that is the last one in the system to heat up and monitor its temperature
while you allow the boiler to fire. Time how long it takes for the radiator to get up to operating
temperature and use that time as the Minimum On Time trial setting. Set the "Man. Override" dial
back to
Auto and the "Cycle Length" dial back to its proper setting. If the Minimum On Time is set
for too short a time, system efficiency will suffer and uneven heating will result as the boiler shuts
down before heat reaches all of the radiators. If the dial is set too for too long, the building will
overheat during the milder weather unless an Indoor Sensor 074 is connected.
With Condensate Return Sensor, this dial = Lockout Diff'l (
°
F)
When there is a Condensate Return Sensor installed to the control, the control monitors the
sensor temperature and will prevent the Establishing Steam (warm-up) period from starting
until the temperature drops to the "Steam Established" dial setting temperature minus the
"Lockout Diff'l" dial setting temperature. To set this dial, turn it all the way up to 50
°F during a
cycle on time and wait until the boiler shuts down. Monitor the temperature of the Condensate
Return Sensor (for sensor placement see
Condensate Return Sensor Function, page 4), and
when the system cools down to the point where the useful heat has been extracted, turn the
dial down until the "Steam Established" light turns off. If this setting is too low, the system will
lose efficiency by not extracting all of the heat from each cycle, and if it is too high, there will
be temperature swings and uneven heating in the building as the system is kept off for too long.