Operating instructions

Troubleshooting
Logamatic EMS RC35 programming unit - Subject to technical modifications
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7 Troubleshooting
This chapter deals with frequently asked questions about your heating system. This will in many
cases enable you to eliminate suspected faults. At the end of the chapter you will find a table listing
faults and corresponding remedies.
7.1 Frequently asked questions
Why do I set a room temperature, even though it is not measured?
When you set a room temperature – even if room temperature is not recorded, as is the case when
the heating control is weather-compensated – you are changing the heating curve. This changes the
room temperature, because the temperature of the heating water changes and with it the
temperature of the radiators.
Why does the room temperature measured with a separate thermometer not correlate
with the set room temperature?
The room temperature is influenced by a number of different variables. If the RC35 programming
unit is installed on a cold wall, it will be influenced by the cold temperature of the wall. If it is installed
in a warm part of the room, such as close to a fireplace, it will be influenced by the heat there. This
is why a separate thermometer can display a different room temperature from that set on the RC35
programming unit.If you wish to compare the measured room temperature with the values recorded
using another thermometer, it is important to observe the following:
• The separate thermometer and the programming unit must be physically close to each other.
• The separate thermometer must be accurate.
• When comparing, do not measure the room temperature when the heating system is heating up,
as the two devices may react at different speeds to the change in room temperature.
If you have followed these instructions and you can still detect a discrepancy, you can calibrate the
room temperature display (Æ page 44).
Why do the radiators get too hot when the outside temperature is relatively high?
If you have a heating system with one heating circuit and no mixing valve (heating circuit 1), this is
normal. The pump only starts up when the boiler reaches a predefined flow temperature. If the flow
temperature is higher than required based on the outside temperature, the radiators may get hotter
for a short time. The heating control detects this and responds accordingly after a short time. Do not
adjust the thermostatic valves on the radiators and wait until the set room temperature is reached.
Even in summer mode, radiators may be heated briefly under specific circumstances: namely when
the pump is started up automatically at a predefined interval to prevent it from “seizing up” (jamming).
If the pump happens to start immediately after DHW heating, the unusable residual heat is
dissipated via the heating circuit and the radiators.