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UH8-RF V2 – Installation manual
Description
The UH8-RF V2 is an 8 Zone central wiring centre for use with
IMI Heimeier RF thermostats.
The UH8-RF V2 can be used to control any actuator or valve, which
requires a 230 VAC signal to open. For mid position valves and those
requiring a closing signal, a changeover relay is required. The UH8-
RF V2 also oers the ability to operate a boiler or other heat source
through a volt free output with changeover contacts, giving you both
a heat on signal and a heat o signal.
Additional outputs designed for use with hot water or underfloor
heating systems, are also included as standard. These are the pump
and valve outputs which would normally operate a manifold pump or
a manifold valve.
Any output which is not needed can be ignored.
Test switches are included for the installation engineer and further
options include creepage protection and pump delay.
Operation
Using the toggle switches, each channel used on this system can be
congured for either a radiator zone or underfloor heating zone.
When the thermostat sends a signal for heating, the UH8-RF V2
will provide a 230 VAC output on the paired zone and also bring on
the boiler/other heat source output. If the zone is congured as an
underfloor heating zone, the UH8-RF V2 will also start the pump and
valve outputs.
If an enable signal is received from a hot water time clock on the
system, only the H/W output will become active. This is a timed
output, which is normally fed to a cylinder thermostat, then to a valve,
but could also be used for towel rails. In either case the valve auxiliary
switch would operate the boiler/other heat source.
Other functions
Creepage
During hot weather the heating is not normally needed as often, this
means that valves and pumps that are not being used can seize and
refuse to operate. To prevent this, it is good practice to operate the
valve or pump once a day, the creepage function does this for you.
Once enabled the UH8-RF V2 will operate each valve or pump for 1
minute, if the outputs have not been operated by a thermostat, within
the preceding 24 hours. This function does not operate the boiler
output.
Pump delay
Some valves or actuators can take more than a minute to open, if
the boiler and pump operate before the valve is open it can force a
boiler to go to lockout and stop operating. This function delays the
operation of the pump and boiler to give the actuators and valves
time to open.
