Q about proportional control of home heater 1

[nifrabar]

Hi!

Hopefully this is not the wrong forum.Otherwise pls advice me.

I am considering to make a pc-controlled central heating system for at home.
Currently the house is heated by a Vaillant VCW255/3 heater. The heater can be contolled proportional by a thermostat in the living. I like to replace the thermostat with a pc. As far as I have understood the gas-valve is indirect controlled by a ventilator inside the heater. The more under=pressure the more the gas valve gets opened.

But..... How to control the fan external.
There are 3 wires from the heater to the currently used thermostat.
The two outer wires provide 24V AC towards the thermostat. The third wire controls (of course together with one of the others) the fan > valve.

Is there anybody who knows what kind of signal is generated by the thermostat to control the heater?

TIA
-Bart

 

[IRstuff]

Are you doing this just for giggles, or are there design requirements you are trying to achieve?

Most home thermostats are not technically proportional, they are bang-bang, since none of the upstream equipment can be used in a proportional system.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

 

[MintJulep]

Looks like you should be able to find the information you need somewhere here:

http://www.vaillant.nl/professioneel/documentatie-1/

If this is a "just because you can" project move the question to forum1528

If this is an actual work related project it's fine here.

 

[willard3]

Read forum policdies which begin as follows:


>>>>>>>These fora should not be used to bypass your own in-depth research on the issues that affect you, nor is it intended to be a substitute for appropriate professional assistance within your field or geographical region.

 

[nifrabar]

Dear all,
Mint Julep, thanks for pointing me to a useable directon.
Without your help it should have been hard to figure out these matters.
IRstuff; bang-bang, such easy, should not require to ask for help from this helpfull forum.
Thread can be considered as closed.
KR
-Bart