Ingersoll-Rand ReliaTel, Manual, Page: 108 / 176

108 RT-SVD03L-EN
Figure 66. Modulating gas heat control process — thermostat control
Immediate call for
W1,W1 + W2, or W2
Set heat output to
100%
Alarm Status. Heat
outputs off.
Start ignition
sequence
Has a flame
been
established?
No
Yes
Output stays at 100%
for 60 seconds
Unit modulates output
down to maintain
discharge air setpoint
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Is the call for
heat satisfied?
Has the heat output
been at 80% for
15 consecutive
minutes?
Is the call for
heat satisfied?
Heat output ramps
to 100%
Heat outputs off
Heat output remains
at 100%
Call for W1 +
W2 or W2?
No
Heat output remains
at 100%
Call for W1 +
W2 or W2?
Heat output remains
at 100%
Call for
W1 only?
Is the call for
heat satisfied?
Is the call for
heat satisfied?
O Op pe erra attiio on n w wiitth h a a C Co on nv ve en nttiio on na all T Th he errm mo osstta att ((C Co on nsstta an ntt V Vo ollu um me e))