Using RGBW air dimmer to control heating

[Yves-Julien Regamey]

Hi,
I thinking of investing into a loxone go , and want to control some 24 V underfloor heating valves (wax type 2 w). I was thinking of using an RGBW dimmer for that purpose .
Did anyone tried this ? Or see a reason that it might not work ?
BR
Yves-Julien

[tzajaczk]

RGBW Dimmer works through a PWM (Pulse Width Modulation). Il some old versions of Loxone Config, there was a parameter which indicates PWM frequency. Right now, the only parameter I saw is a Perception Corrction for a human eye.

In the Loxone Config version 7.4.6.1. you'll see "configurable frequency" but there is no configuration parameter ... as in 8.0.7.19



There is no way of using PWM dimmer to drive a heating 24V valves

But ... you can use the "Intellignet Room Controller" with an output : "Q" for PWM digital output valves

Hope it helps.

[Duncan]

if they are a wax type, then they rely on the heating effect and these valves should be either on or off but dont offer any proportional control i presume - in theory then pwm control will work fine, because the response time of the heater/wax will be a lot slower than the pwm frequency,but you would need to set the configuration so that the pwm output is fully off or on to get the valves to work

[Yves-Julien Regamey]

Hello,
Yes they are waxtype so if I Think using the following schemes it should work. Though I m not sure if I have to include the RGB controller ...
What do you think ?

[Thomas]

Dear Yves-Julien,

You have to understand that a wax-type valves (24V or 230V) uses a PTC resistor-heated elastic element and a compression spring. The wax element is heated by applying the operating voltage and moves the integrated piston. The force generated by the movement is transferred on the piston lifter and thus opens and closes the valve.

On the Normally Closed (NC) valve, the valve is opened steadily by the piston motion upon switching on the operating voltage and AFTER EXPIRY OF THE DEAD TIME. The wax element cools down after the operating voltage is cut and AFTER EXPIRY OF THE HOLD TIME, the valve is closed evenly by the closing force of the compression spring.

The DEAD TIME and the HOLD TIME can be about 3 MINUTES !!!

Using RGBW dimmer gives you the working frequency about 400 Hz (pulses by second) or even more (600 Hz)
Using wax-type valve, you are about 6 minutes OFF so if your pulse is 1 by 20 min it means: 0,00005 Hz

Those valves are used for floor heating system with the high inertia of a concrete floor ...

Your schema :

... is goo up to this point. Intelligent room controller is auto-adaptive : it takes a while to detect the zone insulation and the PWM frequency.
Put the temperature and the Q output on statistics and "wait and see".


Hope it helps.

[Duncan]

if you simply use the rgbw controller as a 4 channel on/off device, the operating frequency of the pwm doesnt matter, and you dont need to use the complexity of the rgb elements

1) add the rgbw driver as 4 consecutive separate dmx channels
2) use each of the 4 channels as outputs connected to the q output of 4 IRC blocks
3) alter the dmx correction parameters so that a 0 output is 0, and a 1 output is 100 - that way the IRC being on will drive the dmx decoder fully on, and it will apply the voltage to the valve actuator with 100% i.e. no on/off at all.

[Santeri / Finlandia Automation Ltd.]

Hi,

does this work on all types of acuators or only wax-type?

Santeri

[Duncan]

it specifically works with off/on types that run on low voltage dc such as 12v, 24v types that the dmx dimmer can switch - the usual limit for dmx dimmers is generally 48v but they all vary,  - they dont have to be wax type but obviously mains 240v would require relay switches and 0-10v types would need to be driven from an analog 0-10v output