Proper Vitodens Programming

Mike T., Swampeast MO

Was just told by someone definitely "in the know" that the Comfortrol still ships with address 042 (Maximum boiler water temp in heating mode) set to 75C or 167F.

Sounds like someone changed the setting during setup.

Perry_3

Proper Vitodens Programming, a\"find\" and a Question

So, today I learned how to program my Vitodens so it would heat the house properly in our current balmy weather (-10 when I checked this AM). But the house was about 60 F.

I knew that something had to be wrong... I had never noticed the boiler temp going above 142 F ever; and I have never seen the LLH outlet above about 135F.

So I dug into the manuals - and checked out the system.

My Vitodens had been originaly programed with a system temperature limit of 131 F (Address 042, setting 055). Now the Vitodens would often overshoot this a bit to reduce cycling.

But, it is not enough to handle near design day weather.

So I changed the seeting to 159 F (065) and watched the boiler kick in and start to raise my system temp. (current target is 149 F based on -4F outdoor temp).


What I don't understand is for a system that was designed to operate at 140 F, and was known to not quite keep up at 140F during the coldest days of the year... - why place a limit of 131 F on it when setting up the program?


I also found that by accessing the diagnostic program that I can read the outdoor temperature, the boiler temp, and the system temp (LLH outlet) at the same time...

One question: Since I have the RS controller - which is susposed to feedback room temp (and does)... Is their any way to get the Vitodens control system to give me a room temp reading on the display? Currently room temp shows up as blank.


Perry

Mike T., Swampeast MO

My manual says that address 042 is set to 75C (167F) by default. The 75C limit is based on EU law that's now a few years old. (Note that the boiler itself can though go up to 172F (78C) for DHW and to maintain 75C in the LLH.

55C (131F) sounds familiar though. I'm thinking it's a newer limit imposed for new residential structures in the EU. Perhaps the Comfortrol now ships with a different setting because of new regulations in the EU.

I'm not positive of this, but from what I've read in Viessmann literature regarding the RS, it doesn't really feed back room temperature, it feeds back the effect of room temperature on the sun/moon dial settings. I suspect if it did feed back actual room temperature that you'd see such in the display. There are other temps (like return temp) that aren't active with the Vitodens either.

Perry_3

I adjusted the setting again - to \"075\"

OK we are below design temps here now - and I adjusted the maximum limit up again. This should work better as I'm now running a supply circuit temp of 160 F.

The partial insulation of the walls is real obvious now... as the inside walls are cold to the touch...

Current reading... -13 F; and off to work I go...

Perry

Glen

defaults

042:075, range is 0 to 82 deg C. And check address 020, should be 001 with RS or WS control unit. Also check timer schedule - often can lead to boiler off - when heat is still needed.

Perry_3

Code 20 is OK

I checked all code address settings for my setup. Code location 20 was correctly set at 1.

I have not yet enabled the clock switching function between day and night schedules. Someday I will do that, but this winter I'm just making sure other things work. I can manually swithch between the two modes on my RS control. Also, this was not the problem in this case.

Perry

Perry_3

Thanks Mike

So, this was programmmed wrong at startup.

Good thing I am computer literate and have all the manuals - now isn't it.

Perry

Mike T., Swampeast MO

Found a Way to Display Room Temp on the Comfortrol

This is weird...

See page 57 of the Start-up/Service instructions. Page numbers might change, but it's the page IMMEDIATELY after the Coding tables.

"The following desired and actual temperature values can be accessed and shown on the display of the Comfortrol programming unit: Outdoor, Boiler, Mixing Supply, Room temperature if Comfortrol programming unit is mounted and used as a remote control." [Condensed some and added some emphasis]

The "Wall Mount Base" (part 7133 385) has a built-in temperature sensor. Insert the Comfortrol and it will act as EITHER the WS remote OR the RS remote. However when you remote mount the Comfortrol you MUST install the "Boiler Temperature Indication Unit" (part 7133-384) in the boiler itself. According to Viessmann literature such indication unit ONLY dislays the "boiler water temperature and fault messages".