OpenTherm protocol PDF document

Forum about Opentherm, Hvac, House heating, Boilers

Moderator: hvxl

phil_in_china
Starting Member
Starting Member
Posts: 8
Joined: Fri Jan 23, 2009 5:58 pm
Location: China

OpenTherm protocol PDF document

Post by phil_in_china »

Then seriously buy an OpenTherm thermostat that will display the information that you want to see. But I fail to really see "why" that info: temperature of the water, speed of the fan, Water pressure etc is needed. The only ones that could be useful is the temperature drop across the flow and return from the boiler and the CH flow rate as these could then could be used to calculate a total load figure for the boiler. Anything else to me is just uninteresting numbers.
With the temperatures (flow and return) you could fit a pair of temperature pipe sensors and for the flow rate you could use a flow meter.

What good is it to know the fan speed is 58Hz and 10 minutes later its 62Hz, does it tell you anything useful? Will knowing that the CH water pressure is 3 bar make your home anymore energy efficient?

Phil
User avatar
Snelvuur
Forum Moderator
Forum Moderator
Posts: 3156
Joined: Fri Apr 06, 2007 11:01 pm
Location: Netherlands
Contact:

OpenTherm protocol PDF document

Post by Snelvuur »

Phil, we are home automation geeks, it doesn't really matter i mean most of us has a temperature reader in every room. Or has a website which shows the speed of the fan of the pc, neither of those you really need to have a normal life/house. But still its just fun to have. We know its possible thats why we want it, not because we want to screw up the intelligent factor behind most heating devices, we just want data. we like data..

// Erik (binkey.nl)
phil_in_china
Starting Member
Starting Member
Posts: 8
Joined: Fri Jan 23, 2009 5:58 pm
Location: China

OpenTherm protocol PDF document

Post by phil_in_china »

Hehe OK I understand, I know person who collects stamps is called a philatelist, not sure what a person who collects any numbers is called?
Anyway here is some more data to add to your collection 0,25,1,14,0,25,1,17,0,25,1,16,0,25,1,24.

Phil
User avatar
RDNZL
Forum Moderator
Forum Moderator
Posts: 1008
Joined: Sun Sep 24, 2006 1:45 pm
Location: Dordrecht, The Netherlands
Contact:

OpenTherm protocol PDF document

Post by RDNZL »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by phil_in_china</i>
0,25,1,14,0,25,1,17,0,25,1,16,0,25,1,24.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

They are no good for me, I have those already [8D]

My point above was, being able to control the heating when I'm away (by the use of the picbasic potmeter trick), and still have the possibility to control it manually and see the temp setting, and heating on symbol when i'm at home. Later when I have more confidence in my HA app, I can settle with only the potmeter control trick I guess.
Note I have a Nefit, so no open-therm, hence the picbasic idea.

Regards,
Ron.
phil_in_china
Starting Member
Starting Member
Posts: 8
Joined: Fri Jan 23, 2009 5:58 pm
Location: China

OpenTherm protocol PDF document

Post by phil_in_china »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by RDNZL</i>
<br /><blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by phil_in_china</i>
0,25,1,14,0,25,1,17,0,25,1,16,0,25,1,24.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

They are no good for me, I have those already [8D]

<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
But I thought you do not have Opentherm?
So how come you already have them?
They are only meaningful anyway to anyone who has OpenTherm ;-)

But to answer your point, so you want two heating controls, one for remote control and one for home use?
Either you will need two thermostats, one for each situation (remote and home)and have a method of switching them in or out of the heating circuit.
Or you could design the PIC mod so that you can switch it in or out
of the thermostat dependent on the need.

Phil
amelia
Starting Member
Starting Member
Posts: 5
Joined: Sun Oct 21, 2007 1:16 pm

OpenTherm protocol PDF document

Post by amelia »

I followed the discussion with attention.
I have an HVAC with Opentherm.
I am building my own integrated home-control:
1- every room as it own system that controls all the local events (light, power, temperature, alarm, ...), sending requests directly to another room or to the central system.
2- every room has it direct hot water supply for cooling, controlled by a modulated-motorized valve, all sited into the central-heating-room.
3- my wish is to be able to modulate the maximum temperature of HVAC depending on the actual requests of all rooms, in the range of 40-55 C, for example; also the temperature of sanitary water can be modulate during the day, using historic consumption-habits tables.
4- depending on the point 3-, I need to communicate with the HVAC, but here I stop my development.

I have on my hands a QAA73 but it does not speak.
User avatar
RDNZL
Forum Moderator
Forum Moderator
Posts: 1008
Joined: Sun Sep 24, 2006 1:45 pm
Location: Dordrecht, The Netherlands
Contact:

Re: OpenTherm protocol PDF document

Post by RDNZL »

I moved to another home a few months ago, so I don't have a Nefit boiler anymore, but these links may interest people having one... :D

wiki.neo-soft.org/index.php/Heizungssch ... ServiceKey

A lot more info and other links are to be found is this long thread...
http://www.mikrocontroller.net/topic/141831

The protocol is called "EMS-bus", eBus seems to be similar...
http://www.mikrocontroller.net/topic/75698#new

Disclaimer:
I cannot be held responsible for any injury, loss, expense or damage of any
kind whatsoever suffered or incurred by any person who uses this information!
Regards, Ron.
Bwired
Administrator
Administrator
Posts: 4704
Joined: Sat Mar 25, 2006 1:07 am
Location: Netherlands
Contact:

Re: OpenTherm protocol PDF document

Post by Bwired »

Thanks for the info
The Germans are way ahead of us!
phoenixb
Advanced Member
Advanced Member
Posts: 512
Joined: Thu Jul 23, 2009 1:00 pm
Location: Netherlands

Re: OpenTherm protocol PDF document

Post by phoenixb »

while originally it's a Dutch invention, right?
__________________
User avatar
Rene
Global Moderator
Global Moderator
Posts: 1689
Joined: Wed Oct 08, 2008 3:54 pm
Location: Netherlands

Re: OpenTherm protocol PDF document

Post by Rene »

Pieter,

When you build the electronics and get it up and running in combination with some software, I can just copy it over to my place;-)
Rene.
Bwired
Administrator
Administrator
Posts: 4704
Joined: Sat Mar 25, 2006 1:07 am
Location: Netherlands
Contact:

Re: OpenTherm protocol PDF document

Post by Bwired »

I have the original service key (tool) from Nefit, with rs232, IR and even bluetooth.
http://www.nefit.nl/SiteCollectionDocum ... cetool.pdf
These links will help me a bit more, but hack, the servicetool is number 23 on my todo list :?
nefit.jpg
nefit.jpg (13.07 KiB) Viewed 16131 times
User avatar
Rene
Global Moderator
Global Moderator
Posts: 1689
Joined: Wed Oct 08, 2008 3:54 pm
Location: Netherlands

Re: OpenTherm protocol PDF document

Post by Rene »

You do not have a second set do you? ;-)
Rene.
User avatar
RDNZL
Forum Moderator
Forum Moderator
Posts: 1008
Joined: Sun Sep 24, 2006 1:45 pm
Location: Dordrecht, The Netherlands
Contact:

Re: OpenTherm protocol PDF document

Post by RDNZL »

@Rene
I have ServiceKey hw and sw laying around here useless, it's a version without Bluetooth, but has IR and serial cable support.
Mail me your address and I will sent it to you.
Regards, Ron.
Bwired
Administrator
Administrator
Posts: 4704
Joined: Sat Mar 25, 2006 1:07 am
Location: Netherlands
Contact:

Re: OpenTherm protocol PDF document

Post by Bwired »

solved :)
gjniewenhuijse
Member
Member
Posts: 140
Joined: Thu Jul 16, 2009 12:04 pm
Location: Netherlands

Re: OpenTherm protocol PDF document

Post by gjniewenhuijse »

Bwired wrote:I have the original service key (tool) from Nefit, with rs232, IR and even bluetooth.
http://www.nefit.nl/SiteCollectionDocum ... cetool.pdf
These links will help me a bit more, but hack, the servicetool is number 23 on my todo list :?
nefit.jpg
Is it already posible to monitor my Nefit with this tool. I have already a service key from nefit.
Post Reply

Return to “Hvac, Heating Opentherm Forum”