Troubleshooting
Faults occurring during operation of the Combi furnace are displayed as an error code on the
CP plus control panel (refer to the Troubleshooting section in the CP plus manual for additional
instructions). The potential cause as well as a solution is described according to the error code
in the CP plus manual.
The potential causes for problems with the water system and the Combi furnace are described
below:
Problem
Water heats up too slowly.
Water drains. / The hot
water container cannot be
refilled.
The water container cannot
be emptied even though
the pressure relief/drain
valve is open.
Water is dripping / flowing
from the drainage socket
of the pressure relief/drain
valve.
If none of the measures in the troubleshooting chart proves successful, please contact your dealer,
the Truma Service Center on 1-855-558-7862 or one of our authorized service partners.
Potential cause
Lime scale (hard water calcifi-
cation) in the water container.
The pressure relief/drain valve
is open.
The drainage socket of the
pressure relief/drain valve is
obstructed.
Water pressure in the water
system is too high.
The pressure inside the water
container rises above a water
pressure of approx. 65,25 psi
(4.5 bar) – Truma pressure re-
lief/drain valve installed.
Water pressure in the water
system is too high.
Lime or dirt under the pres-
sure relief/drain valve seat.
Solution
Decalcify the water container
(refer to "Decalcifying and cleaning
the water container" on page 17).
Close the pressure relief/drain valve.
Remove any obstructions such as
slush, ice, or leaves from the open-
ing of the drainage socket.
Make sure that the faucets are
opened in the position "hot".
Check the pump pressure and ad-
just if necessary. Replace the wa-
ter pump if an adjustment is not
possible.
Ensure that a pressure reducer is
installed on your city water con-
nection, not exceeding 40.6 psi
(2.8 bar).
The Truma pressure relief/drain
valve protects the water container
against a pressure greater than
65,25 psi (4.5 bar). This is not a
fault. If the condition continues,
contact Truma service.
Replace the water pressure reducer
at the fresh water supply. This must
be performed only by a qualified
service technician.
Rinse the pressure relief/drain valve
to remove contamination from the
valve seat (refer to "Draining the
water container" on page 13).
Replace the pressure relief/drain valve.
This must be performed only by a
qualified service technician.
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