I have a gas heater in the attic and 2-zone thermostats, one upstairs & one downstairs. The problem is upstairs heating. The Flame doesn't stay ON long enough (3 minutes max, see below). For your info, I have recorded the sequence and time for both operations.

Sequence Downstairs Upstairs
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Ignitor ON for 30 sec 34 sec
Gas valve Open & Flame ON for 50 sec 49 sec
Blower ON for 8.5 minutes 3 minutes
Gas valve Close $ Flame OFF for 4 minutes 4 minutes
Blower OFF

Could the problem cause by the heat anticipator inside the thermostat?

Please help