[OpenTRV-interest] Tinkering kit / Conrad radiator valve and security code

Mon May 19 10:24:53 BST 2014

Last night I tried to fit my Conrad TRV to a radiator, in order that I
could try to establish a dialogue between the TRV and my OpenTRV tinkering

Fitting the TRV proved to be a very frustrating experience, primarily
because the Conrad instructions assume that you have additional kit, and
that some relevant instructions will be available in the instructions for
that kit.

Conrad instructions for "Valve Drive 57 00 56":

"In the case of valves made by Danfoss, you first have to put on one of the
supplied adaptors (see the operating manual for the complete system)".

Here's a link to the Conrad website for the Valve in question, which has
been sitting next to my PC for the past 6 or 7 weeks:



I found the clue that I required in the manual for the other part in this
2-piece set:


Here's the link to the manual for the FHZ1000 set:


The photos marked figures 10 / 11 / 12 are included in the instructions for
the Valve, tiny pictures of course, but the photos marked figures 14 / 15 /
16 are NOT in the valve manual. The fittings on my radiators required the
adaptor that is identified in figure 14, "type RA". It wasn't clear to me
that this was the correct fitting, mostly because it's by no means a snug
male/female fit. The nut and bolt hold the collar around the existing
metalwork, but there is no lip or ridge that could prevent movement of the
collar. I don't know if this is a peculiariaty of my fitting, or if all
Danfoss "RA" would be like this (mine doesn't exactly resemble the

Additionally, I used a plastic extender for the radiator actuator pin; this
was supplied with the Conrad Valve (and is probably visible in the manual
in figure 15). But right now I can't say that it's correctly positioned, or
if the movement in the valve actuator up to the time might have knocked it
out of position. The pin and extender piece - both currently hidden from
view - have rounded tips, so although the pin does have a recess that
allowed me to place it appropriately on top of the existing radiator pin, I
don't know if the movement of the actuator pin will cause it to move out of

Which brings me to my next point.

I followed the instructions in the Valve manual for setting up the valve.
Refer back to 550000-574999/570056-an-03-ml-Ventilantrieb_de_en_fr_nl.pdf .
As the valve is powered, I see the readouts described in the manual. First
C1, then "93", then C2, then "74", then A1. I understand that 93 / 74 is
the house code pre-programmed into this valve.

Manual states to press the button for 3+ seconds to put the valve into a
state where it may expect to receive a "security code". The valve has been
awaiting this security code since ~1am last night.

I logged in to the openTRV controller (it has either lost ~10 minutes in
the past 7 weeks, or I must have switched it off / on at an appropriate
time -10 minutes past midnight?). I previously reported that my controller
did NOT reboot when I fired up the Arduino IDE. Certainly today (a few
minutes ago), it DID reboot; the first things that I saw in my terminal
screen were the reboot messages.

Last night I tried to execute the House Code command to the controller. It
looks as though it has succeeded somewhat; every line of output now
terminates with "HC93 74 s".

I also got some new "FHT8V" messages, and I don't know what to make of

Here's some output from last night. I've removed some greater than signs
from the output, in case your mail reader might misinterpret or hide the
lines in question.

"Normal" output, before I started tinkering:

=F0%@22C7;T0 50 W255 0 F255 0 W255 0 F255 0;S10 10 21 cffO

So I tried to send the "Set Wireless House Codes" command, per the help
text, and using the codes displayed by my Conrad valve:

H 93 74
=F0%@22C7;T0 50 W255 0 F255 0 W255 0 F255 0;S10 10 21 cffO;HC93 74 s
50:52:0 FHT8V SYNC...

So the output has ";HC93 74 s" appended, and some new output has begun to


More "normal" output, with the HC stuff at the end:

=F0%@22C8;T0 51 W255 0 F255 0 W255 0 F255 0;S10 10 21 cffO;HC93 74 s

And some exciting new output, which I don't know how to interpret (this was
around 1am; the OpenTRV board seems to be saying that it is 0:55am in the
output below):

54:52:73 FHT8V TX
=F0%@22CA;T0 55 W255 0 F255 0 W255 0 F255 0;S10 10 21 cffO;HC93 74

56:48:73 FHT8V TX
58:44:73 FHT8V TX
=F0%@22CA;T0 58 W255 0 F255 0 W255 0 F255 0;S10 10 21 cffO;HC93 74

Here I input the correct time at 1:04am:
T 01 04
=F0%@22CA;T1 4 W255 0 F255 0 W255 0 F255 0;S10 10 21 cffO;HC93 74

66:40:73 FHT8V TX

This morning I am getting stuff like:

610:26:74 FHT8V SYNC FINAL
612:22:73 FHT8V TX
=F0%@23CD;T10 12 W255 0 F255 0 W255 0 F255 0;S10 10 21 cffO;HC93 74

614:18:73 FHT8V TX

However, my Conrad TRV still seems to be awaiting receipt of a "security
code". I would like to send this from the OpenTRV controller, but I can't
figure out from the help text what I should send (and is timing
important??). The valve STILL shows "AC" with a flashing antenna; so
according to the manual it's awaiting said code.

So ... how do I send it?
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