8
ISOTHERM-IM-DE-W-UK-01-2021-Rev0 | Part no. 10019091
EN
ENGLISH
9 Troubleshooting
Problem
Possible cause
Solution
1
The heating circuits of the surface heating are not heated up
1.1
The temperature limiter switches off the circulating pump of
the compact control station.
Cause
: the temperature limiter is set to a very low value.
Set the temperature limiter by approx. 10 K higher than the
supply temperature for the surface heating.
Attention
! Take into consideration the surface heating max-
imum allowable temperature!
Instruction
: The difference between the switch-on temper-
ature and switch-off temperature of the temperature limiter
is around 5 K.
Useful tip
: The control station may be ready for operation
sooner if the temperature limiter is removed for a short time
to allow its cooling down to the switch-on temperature.
1.2
The temperature limiter switches off the circulating pump of
the control station.
Cause
: Initially, the circulating pump remains switched on
even when all of the heating circuits of the surface heating
are blocked. The water circulating on “idle running” through
the bypass is heated up by the circulating pump’s waste
heat. On reaching the maximum temperature, the tempera-
ture limiter switches off the circulating pump!
Remove the temperature limiter from the control station and
install it at the supply line or, eventually, at the return line of
the heating circuit manifold.
Use an electrical connecting box with pump relay (pump
logic). Due to the relay, the circulating pump operates only
if at least one heating circuit of surface heating is opened
(requires heat).
1.3
The circulating pump is connected to a room temperature
thermostat or to a electrical connecting box.
If all the actuators close, the pump is switched off. If the
idle period is longer, the supply water for surface heat-
ing is cooled down. Therefore, the injection mixing valve
opens and hot water is injected from the primary circuit. As
a result, the control station is heated up. On reaching the
temperature limiter’s switch-off temperature, the contact
opens. The pump will not switch on again.
Remove the temperature limiter from the control station and
install it at the supply line or, eventually, at the return line of
the heating circuit manifold.
Subsection 1.1 should also be taken into consideration.
1.4
The difference between the temperature of the boiler’s sup-
ply water and the required supply temperature of the sur-
face heating is too small for the existing heating load.
Set the boiler's supply water temperature to a higher value.
At maximum power consumption in the heating circuits of
the surface heating, the Heating boiler’s supply water tem-
perature should be at least 15° C higher than the required
supply temperature for surface heating!
1.5
The thermostatic injection valve is leaking due to debris.
Remove the manual setting wheel and the cover of the
injection valve's body, take out the inside parts and clean
everything. (See the dedicated manual)
2
The supply water temperature cannot be set tot the required value of it fluctuates within a very wide range
2.1
The control station’s supply (inlet) pipe and return (outlet)
pipe are connected to the manifold in the wrong way.
Check all inlets and outlets of the control station for correct
connection. Supply inlets and return outlets are marked with
stickers.
Please take into account Fig. 8-2 and Fig. 8-3 on page 6
2.2
The circulating pump’s pressure head/pump stage is set at
a very high value.
Increase the rotation frequency, the pump pressure head/
pump stage, respectively.
2.3
The heating load is too big for the control station used, i.e.,
the heat consumption exceeds the rated power of the con-
trol station. This state may set in temporarily, e.g., in case of
heating a “cold” floor for the first time.
TCheck the maximum heat consumption and compare it
with the rated power. If necessary, distribute the heating cir-
cuits to a second control station with a respective manifold
for heating circuits.
If the cause is in the initial heating up of a given surface heat-
ing system, the function may be normalized after the heating
up phase. This is possible chiefly in an operating mode within
the top values of the rated power
With installation of a control station ISOTHERM into a heating system with boilers with small water volumes, with combined
radiator and surface heating systems or with plants with warm water priority function the installation of a hydraulic separator
between boiler and heating circuit is recommended, in order to disconnect the heating circuits hydraulically from the boiler.
Thus operational disturbances as well as supply noises at the boiler and/or in the heating circuits can be avoided.
