Computherm Q4Z, Operating Instructions Manual

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circuit). If there are no such zones, then in order to prevent the heating system 

from an event in which all heating circuits are closed but a pump is switched on, 

the zone controller has two types of delay function.

5.1 Turn on delay

If this function is activated and the outputs of the thermostats are switched off, 

then in order to open the valves of the given heating circuit before starting the 

pump(s), the zone controller 

NO

-

COM

 and 

Z1-4

 output, and depending on the 

zone the 

Z1-2

 or 

Z3-4

 output switches on only after a delay of 4 minutes from  the 

1st switch-on signal of the thermostats, while 230 V appears immediately at the 

output for that zone (eg. 

Z2

). The delay is especially recommended if the zone 

valves are opened/closed by slow-acting electrothermal actuators, because their 

opening/closing time is approx. 4 min. If at least 1 zone is already switched on, 

then the Turn on delay function will not be activated when additional thermostats 

switch on. 

The active state of the Turn on delay function is indicated by the blue LED flashing 

with 3-second intervals. 
If the “

A

/

M

” button is pressed while the Turn on delay is active (blue LED flashes 

with  3-second  intervals),  the  LED  stops  flashing  and  indicates  the  current 

operating mode (Automatic/Manual). Then the working mode can be changed 

by pressing the “

A

/

M

” button again. After 10 seconds, the blue LED continues to 

flash with 3-second intervals until the delay stops.

5.2 Turn off delay

If this function is activated and some thermostat outputs of zone controller are 

switched on, then in order for the valves belonging to the given zone to be 

open during the recirculation of the pump(s), the 230 V AC voltage disappears 

from the zone output of the given zone (eg 

Z2

), output 

Z1-4

 and, depending 

on the switched zone, output 

Z1-2

 or 

Z3-4

 only after a delay of 6 minutes from 

the switch-off signal of the last thermostat, while the 

NO

-

COM

 output switches 

off immediately. The delay is especially recommended if the zone valves are 

opened/closed by quick-acting motorized actuators, as their opening/closing 

time is only a few seconds. Activating the function in this case ensures that the 

heating circuits are open during the circulation of the pump and thus protects 

the pump from overload. This function is only activated when the last thermostat 

sends the switch-off signal to the zone controller.
The  active  state  of  the  Turn  off  delay  function  is  indicated  by  the  3-second 

interval flashing of the red LED of the last zone switched off.