Viessmann question

Simply Rad_2

I see says the blind man
Great job Bernie. Your eyes are 20/10. Told you somedays I see 20/100. I was looking at the F-05 which leads me to the fan speed/combustion. Steve has an F-5 which leads to a mixing valve sensor problem. Steve how are you with the fault. Thanks Bernie for the clarity.
Jeffrey

Steve Ebels_2

Got one making me nuts..........

I've been working sans cell phone for the last week due to location and haven't taken the time to call James regarding an intermittent fault. I hate to call the poor guy after hours for a non emergency situation so I'm throwing it out here to see if anyone has run into this or has an idea what I'm overlooking.
The system is an 8-32 Vito with circuit A (panel rads), circuit B (mix valve for floor) DHW and a LLH. The fault that appears about every 2-3 days is an F-5 which is a mixing valve problem or a communication problem with the mix valve. I've triple checked all the connections, wiring and programming and it all looks to be correct. At least to my eyes and in accordance with the installers manual.

When I clear the fault it'll stay gone for 2-3 days and then show up again. The system seems to be operating correctly on all circuits yet the fault still shows up. What's going on?

Simply Rad_2

Still driving you nuts?

I just started up a system using a two temp distribution for radiant and radiant panels. I installed Roth panel over existing slab and Myson Panel radiators in the upper level. I used the Viessmann 3 way and actuating valve. Mine is running great. I will look at the manual today at the job. You said it was an F-5. I need to figure out how to display the 3way sensor temperature on the comfortrol? I figure if I atleast post it will bring the subject back up to the top. Maybe someone else will post.
Jeffrey

J.C.A._3

Steve,

Have you done an OHM check on the mixing valve sensor to see if it's in the ballpark?

Don't know why, but I've had a couple of 10K sensors go bad in the last couple of months. The computer is only as good as the information it's fed and if it goes out of whack in any way, it will show as some kind of fault code to protect itself.

Let us know what you find. Inquiring minds want to know! Chris

Mi39ke

VITOTALK 4

Just scanned through the back issues of VITOTALK and #4 seems to talk about mix valves and Vitodens to a great extent. Good reading, even if you don't find your answer.

Michael Ward

myles_2

f-5 fault

Steve please check the the fan the speed may be to low at start. also check your venting for cross contamination.

Simply Rad_2

F-5 Fault

I was able to look at installation manual and yeas look at fan speed and cross contamination. Use a combustion analyzer to test the combustion air for CO2. I know you can change fan speed if needed also. Does anyone know if the Comfortrol can produce the mixing valve sensor supply temeprature?
There's my 2 cents
Jeffrey

S Ebels

What am I missing?

(I mean besides the various body parts they have taken out over the years)

The F-5 fault code alludes to a mixing valve problem. What's up with checking the fan speed and CO2?

BTW the mix valve is operating normally from all appearances, although it is hard to tell because the weather has been mild. That's about to change according to the NOAA website. Winter is here.

Simply Rad_2

Are you missing your eyes?

Steve
Here is the information straight out of the Vitodens 200 start up and service book.
F-5 Burner fault(red light) Burner control swithces to lock out. Cause of fault= fan speed too low(incorrect fan RPM). Corrective action check fan and flue gas system.
What manuals are you looking at that tells you its a mixing valve problem?
Jeffrey

S Ebels

Hmmmmmmmmm

The Vito manual that I have (5285 583 v1.0 10/2003) says the following on page 30 and 31:

Fault F5:

Burner fault indicator (off)

System behavior: -- (in other words, variable)

Cause of fault: Error message extension kit for heating circuit with mixing valve

Corrective action: Check coding for extension kit and the extension kit itself. Check sensor 2 of mixing valve

Check yours and see what it says. Maybe I have a typo. Still have my eyes @ 20/15 vision. (with glasses)

Simply Rad_2

Vitola or Vitodens

What boiler did you install. You keep saying Vito that could be Vitola or Vitodens. I am reading from the Vitodens 200 Guide. I believe the Vitola uses a different control which would explain the mix up. If it is your sensor perform an ohm test there is also a chart with the valve actuator-temp VS resistence. Some days my eyes are 20/20 others tthey are 20/100? This morning is a good day to test systems outside temperature here is 8 degrees.
Good Luck Jeffrey

S Ebels

Sorry

It's an 8-32 Vitodens. There is no 8-32 Vitola. The manual I'm reading from is for a Vitodens 200 boiler Startup/Service Instructions.

J.C.A._3

No questions on your eyesight ...Steve

But, again....I'm going to refer to a couple of sensors that have proven faulty in the last couple of months.

Maybe it's an environmental condition that is rearing it's ugly head when noone is awake/around to observe.Something maybe dumping water on a sensor area that drys out before it is noticed ? Could even be a "misplaced" sensor. I've seen that more than once.
In the cases of bad sensors, I actually placed another 10K in the same area to compare the outputs and it showed that one was way off, and it proved to be the one attached to the control panel.A sensor giving a high temp. reading WILL cause a "low fan speed" if it only wants to modulate a little bit as opposed to what the other sensors are telling it, and there a quite a few other perameters that will tell the main computer what is or ISN'T happenning.
Most are great and last a long time, but they are mechanical devices and are prone to failure. Just my 2Cents
Chris

bernie_3

Each of you are looking at the same manual. One is looking at an F5 fault and the other is looking at an 05 fault(page 32).

S Ebels

Wierd

The mixing valve circuit and everything on it are functioning normally as far as I can tell. The fault still shows up but no change occurs in system operation. Even though the sensor ohm's out OK, I'm going to change it later this week and see what happens. It's an interesting problem.

[Deleted User]

Glen

sensor wire -

are you using shielded sensor wire. Had a similar problem with a Vertomat sensor - temps went sideways when the shop lights were turned on. shielded wire corrected it. The goodfy fault drove me nuts for a time ....

S Ebels

That'll be

That'll be the second course of action that I try. I'd like to do these one at a time so I can positively identify what was causing the fault. There is nothing that I can see which would cause freaky, stray EMF or current. Incadescent lighting and no other major electronic stuff in the boiler room. Having fun with this one.