oventrop Uni LH Installation Instructions For The Specialised Installer page 4

Replacement of the gland nut
Remove the thermostat from the valve. Unscrew the gland nut
with a 14 mm key. Water will not escape as the valve is provided
with an additional seal. Screw on the new gland nut (item no.
1017501) and tighten with the key. Refit the thermostat.
SW = Spanner size
Note
Not for thermostatic valves "A" (since 2013), "AV 9", "AV 6",
"ADV 9", "ADV 6", "CV 9", "RF" (since 2014), "RFV 9", "RFV 6",
"E", "AQ", "RFQ" and "EQ".
Disposal
To protect the sensor liquid from escaping, the thermostat must
not be destroyed when disposed of. The thermostat contains
hazardous waste! Dismounted/defective thermostats can be
returned to the manufacturer Oventrop. They will be disposed
of professionally.
Checklist for troubleshooting
The required room temperature is not reached or maintained:
11. The flow temperature is set too low.
12. The circulation pump is not switched on.
13. The circulation pump or the flow temperature is controlled
by a separate room thermostat.
14. The pump output is set too low.
15. The flow direction of the pump is wrong.
16. The heating pipe is throttled back or shut off.
17. With gravity fed heating systems, a circulation pump must
be installed subsequently if necessary. Gravity systems are
very sensitive to the presence of air in the system.
18. The radiator is covered by curtains, panelling etc. Use a
thermostat with remote sensor or remote control.
19. The temperature at the thermostat differs widely from the
ambient temperature due to poor siting. Use a thermostat
with remote sensor or remote control.
10. The remote sensor or remote control is badly sited. The
best height is about 1 m above the floor level.
11. The radiator selected is too small for the size of the room.
12. If the required temperature is only reached at a higher
setting of the thermostat, recalibrate the thermostat (if
required).
Subject to technical modifications without notice.
Product range 1i
Edition 2017
4
Gland nut
Thermostatic radiator valves
Thermostats "Uni LH" and "Uni LD"
The thermostatic radiator valve does not function:
13. The thermostat is not screwed tightly onto the valve.
14. The capillary of the remote sensor or remote control was
kinked or flattened. Use a new thermostat and fix the
capillary carefully!
15. If a strainer is used, has it become blocked? Remove the
valve, flush the pipe thoroughly, clean the screen and
re-install the strainer.
16. Air is reducing the circulation in the radiator. Vent the
radiator.
17. Air is impairing the circulation in the heating riser. Fit an
automatic airvent at a suitable location.
18. The valve insert was damaged, for instance as a result of an
improper assembly in a vice. Fit a new valve.
19. The thermostat was misadjusted due to unauthorised
tampering. Recalibrate the thermostat (see page 3).
The valve cannot be shut off:
20. In most cases this is due to dirt particles on the valve disc,
such as welding beads or rust particles. These particles can
often be removed by repeatedly actuating the valve stem.
To do so, the thermostat must be removed first. If the valve
disc was damaged during this operation, the valve insert
must be replaced. This can be done without draining the
system with the help of the "Demo-Bloc" tool which was
especially designed for this purpose.
If this is not successful, the valve insert must be removed
after having drained the system and the dirt particles
have to be removed from the valve or the valve has to be
replaced.
21. The frost protection responds. The crystal symbol 
corresponds to a room temperature of about 7 °C. The
valve will therefore open as soon as the temperature drops
below this level, for instance when airing the room.
22. The thermostat is defective and has to be removed. First
test whether this is due to dirt or unauthorised tampering
of the calibration. Screw on a new thermostat and return
the old one to the supplier. If still under guarantee, it will be
repaired or replaced free of charge.
The valve leaks:
23. The gland nut is loose. Tighten it.
24. The O-ring seal of the gland nut is damaged. Replace the
gland nut. The system does not have to be drained for this
purpose (see point 20).
25. The valve insert is loose. Tighten it. If necessary, use a new
insert (compare point 20).
The valve rattles:
26. Supply and return were mixed up.
Flow noises occur:
27. Can the pump head (differential pressure) be reduced?
Please contact the manufacturer in case of further questions.
2017