OWB and Vitodens
Trying to get my Central Boiler classic edge connected into my heating system. Currently I have a 90 plate heat exchanger in the primary loop with a low loss header. The issue I have is being able to keep my vitodens powered on but not running when I am burning wood. I’ve had a Viessmann rep here trying to adjust settings based on aquastat incoming from OWB, but we have not been able to keep the Vitodens from firing. To date, I just power the Vitodens off while heating with wood, but I’d really like to have the backup in case of fire going out.
Something I have considered is running a 45 gallon dual coil indirect storage tank with my OWB on one coil and the Viessmann on the other coil. Then putting in an aquastat in the storage tank to control the Viessmann. I would assume that this would work, but is it the best application?
For clarification, my OWB modulates its own temperature to keep water temp between 175-185F. I’m running radiant heat in the home with an indirect storage tank for DHW.
Thanks in advance for the help!
Comments
-
Put an aquastat on the OWB supply and interrupt the TT signal to the Vitodens with it. Then it'll only kick in when the OWB is below setpoint. I do this all the time and it works flawlessly.
1 -
Which Viessmann Boiler?
If the Boiler has a LLH and a accociated sensor the Viessmann should modulate down when you apply an other heat source such as the Outdoor Wood boiler…Can you please post some pictures.
0 -
Do you have a freeze protection method for the OWF? What protects it if the fire goes out and you are running on the Viessmann?
How are you mixing down for the radiant? Is it a mix valve with outdoor reset?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
It is a vitodens 200 boiler. Here are some pictures.
For reference I have a 6 way relay switch that is connected to the vitodens and controls the circ pumps for the 6 zones. The relay switch is connected to TT I believe. The 90 plate heat exchanger is in the primary loop and that circ pump is always running keeping the water circulating through the LLH.
What ends up happening is the Viessmann will fire and then basically short cycle. What I’d like is if the Viessmann didn’t fire up at all unless necessary.
0 -
VITODENS 100 OR VITODENS 200.?Do you have the Low loos header sensor installed?
0 -
0
-
I have a thermostatic valve which basically sends a couple gallons of hot water back to the OWB for freeze protection. The issue right now is that I keep the Viessmann off it doesn’t keep short cycling. So essentially I have no freeze protection at this point. I have mixing valves at each zone to bring temp down to radiant temps.
0 -
Setup the Viessmann like they do in Deutschland...Constant circulation and adjust your curve/ Shift ...If you have a 200 you may be able to use the Solar programming aspect of the Viessmann to you advantage.
0 -
vitodens 200. And yes, I do have the sensor installed. Thought the sensor was the issue. I don’t know what temp the Viessmann likes to keep the LLH at.
0 -
If it's setup correctly the Viessmann will base the LLH temperature on the outside temperature and any negotiations to the programs..i.e room temperature.
Have you Ohmed out the LLH sensor yet?
0 -
I’m not sure what ohming out the sensor entails, so I’d probably say no, I haven’t. Maybe they did on install.
0 -
Or just wire in the aquastat as mentioned above. No need to try to reinvent the wheel
0 -
The first part, keeping the V off is as simple as @GroundUp mentioned.
A sensor wire to the OWF would be helpful to know it's temperature to make the on/ off decision.
There is a piping arrangement to use a small shunt pump controlled with a tight delta to offer freeze protection. Instead of running the large OWF pump. Shown below.
You want to use the least amount of the Viessmanns output for freeze protection, or that will get $$ I guess it depends on how often the OWF is left unattended in the winter? Someone needs to feed the beast, daily.
With thermostatic mixer on the radiant you will need to run the boiler temperature 15- 20 degrees hotter that the desired SWT. Running the boiler direct to the radiant or a motorized mix valve would allow you to use the Viessmann onboard ODR
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Ohming the sensor means. Checking the resistance of it and making sure that it is in accordance with the temperature it is subjected to...
0 -
The Vitodens 200 series boiler has many features build into the coding....Coding level 2 is the one you want to look into…adding an aquastat will just complicate things. can you please take some picture from further away.
0 -
here’s a picture from further away.
so I have an aquastat on incoming water from OWB. Set it at 150F. OWB pumps out 175-185F water. Aquastat is hooked into DE1 on Viessmann. 6 zone switching relay from zone thermostats control zone circ pumps. The switching relay is hooked into TT on Viessmann.
turned on controls in coding level 2 to enable DE1. Boiler still fires on despite having 180F water incoming from OWB.
0
Categories
- All Categories
- 86.5K THE MAIN WALL
- 3.1K A-C, Heat Pumps & Refrigeration
- 54 Biomass
- 423 Carbon Monoxide Awareness
- 96 Chimneys & Flues
- 2K Domestic Hot Water
- 5.5K Gas Heating
- 101 Geothermal
- 157 Indoor-Air Quality
- 3.5K Oil Heating
- 64 Pipe Deterioration
- 929 Plumbing
- 6.2K Radiant Heating
- 384 Solar
- 15.2K Strictly Steam
- 3.3K Thermostats and Controls
- 54 Water Quality
- 42 Industry Classes
- 48 Job Opportunities
- 17 Recall Announcements