27
2. Optical detection:
The red LED on the board is lit if the flame
is good, which is an indication of proper
combustion.
1. Remove the connection cover.
2. Observe the LED labeled S.
3. Start the Combi furnace in hot water mode.
4. If the LED becomes red 5 seconds after the
gas valve opens (clearly audible noise), com-
bustion is good.
Static pressure test
The Combi furnace has an automatic fan speed
control.
Truma recommends that all 4 warm air outlets
should be fitted with warm air ducts.
1. For testing, close all warm air outlets but
one. The static pressure should be below
0.65 in. wc (1.6 mbar).
2. Repeat this for each duct connector.
Contact Truma Service, if you need further
recommendations and specifications for
optimized performance and proper operation.
Final check of installation
For the final check of the installation, refer
to the installation checklist supplied by
Truma.