3 or 4-way valve regulation adjustment Centratherm ZG 254 for heated floors?

[Christophe]

I have just resoldered (about 1 year late) the "clock" part of which 1 end of the plate was "broken into 2".

The clock ticks it's a good sign, by moving it by hand, it never stops the circulator.

I would indeed, preferred that the circulator be stopped completely "at night" rather than lowering the setpoint (electricity saving) you think it is possible or not with the centratherm of which I give the photo:



According to the doc it does not seem possible ... https://www.econologie.info/share/partag ... NR0djs.pdf

For the moment the circulator is managed by the thermostat in the living room.

[swift2540]

For the moment the circulator is managed by the thermostat in the living room.

Is the thermostat not connected to the external regulator?
If the TA cuts the circulator, why cut it in + with the regulator?

The doc in French: https://www.econologie.info/share/partag ... 3eIEqL.pdf

[Christophe]

Is the thermostat not connected to the external regulator? If the TA cuts the circulator, why cut it in + with the regulator?

Well not to make it run at night (off-peak hours) ... but it may be an FBI (false good idea) ... given the thermal inertia?

Thank you for the doc in FR.

[Christophe]

Here are some pictures of the interior of the centratherm ZG254 taken for this topic: voltage-of-the-battery-located-in-the-centratherm-clock-t8818.html

[dirk pitt]

... Well not to make it run at night (off-peak hours) ... but it may be an FBI (false good idea) ... given the thermal inertia?
.

if you turn off the circulator, the heating power goes to ZERO so you no longer have any regulation.
it's a choice
this implies that the restart will be longer and will depend on the temperature at which the floor is lowered. so you will have a hard time controlling the time when the comfort temperature returns.

[Christophe]

My Centratherm regulation (which has still worked every winter since the creation of this subject is 2008) seems out of order.

It lights up but can no longer regulate the 4-way valve other than around the minimum heating position ... I presume that electronic components have aged (potentiometer, capacitor ..) and no longer give the right values ...

The action on the adjustment potentiometers no longer has any effect whatever the temperatures ...

Or it is one of the 2 temperature probes which is out of order: I have one outside and one on the valve outlet (therefore the underfloor heating inlet) ...

After nearly 40 years of service I think it deserves to be changed ... unless there is a simple solution? I don't really want to spend time on this site ...

[Christophe]

The cow !! I can not believe ! The Centratherm ZG 254 regulation is still available (old stock or reconditioned: 320 € anyway ...)! Proof that it's good stuff!

So I found the wiring and I will be able to test the 2 probes (thermistors apparently):

centratherm-zg-254-kk-wf-with-analog-clock-tp ~ 2.jpg (128.51 KiB) Viewed 2656 times

[Christophe]

Here are the datasheet of the AF20 and VF20 probes, they are NTC 20K thermistors, there is even the table of values ​​to check if they are still ok :

Screenshot 2021-11-02 at 13-14-23 vf20-ft-fr0c0008fr03r1295 pdf.png (62.99 KiB) Viewed 2650 times

Yapluka!!

If they are ok it means that the regulator is out of order and I would try to find a new regulator compatible with NTC 20K probes ...

ps: the TW20 (room thermostat) is optional and had never been wired to my installation ...

[Christophe]

I measured VF = 50 kOhm and AF = 48 kOhm ...

According to the table above, 48 kOhm = 7 ° C which is seems right ... but 50 kOhm = 6.5 ° inside

The indoor sensor therefore seems out of order since it indicates a lower value than the outdoor sensor ...

Which explains, logically, that the setpoint is blocked on the coldest! So I have hope that the regulator is still working!

You just have to change the interior sensor!

[GuyGadeboisTheBack]

I admit .... all this is exciting! Almost bewitching! (I go out)