Viessmann 200-19: Using a simple thermostat

TAG

I'm trying to understand what the fancy room controller does vs just using a dry contact thermostat -- what about not having one at all? I'm assuming the boiler controls are like the Buderus Eccomatic/Logmatic -- where the special room Thermostat (think Buderus called it a BFM) is really a modifier. It allowed you to lower the curve and use/not use a setback w/o going down in the basement to the boiler and changing any of the settings. BFM also had an internal sensor -- so it would adjust the curve base on thermostat location space. Is that what the Viessmann does ?

Reading the literature for the Viessmann it seems the boiler can also use a simple thermostat -- is that just going to modify if the temp is reached? High limit maybe? That may be useful in my application as it's going into my weekend house -- with internet thermostat I could remote control a setback.

The first Buderus install I bought the BMF -- actually two -- both the high temp curve for the radiators and the lower temp floor zone. They were really expensive back in the 90's. After I understood how they operated .... I did not use them again. With proper tweaking -- I found they were not necessary.

GW

Yes you’re talking about the Viessmann with the DE terminals. Try not to overthink it. It simply calls the boiler to make heat. Which Viessmann model? There has been a revision. Older B2HB models have the DE terminals but it’s a small pain to program the basic thermostat input. The current B2HB boilers it’s total cake to use the DE terminals for basic stat use.

As you may know- bud 2107 you can not tie a basic stat to it. And the room sensor is BFU, so BMF must be before my time. If you had two that must mean you had a low temp system (mixing valve)

I could blabber on a bit

TAG

GW: It's a Viessmann B2HA 200W-19. Correct: The Buderus ODR system I speak of was prior to the 2107 and they called it Eccomatic. optional room control was the BFM. I did four of them. It was expandable and would take two mixing modules for lower temp water. My first had both tile and wood floors in addition to the radiators.

My later ones and the only 2107 I did was set up without any room thermostat. Turning them on for the season was through the outside temp sensor.

So with the Viessmann a dry contact thermostat will turn it off and on ? Sort of defeats the ODR .... Guess I could use it as an "On/ Off" switch.

The Buderus BFM had a built in setback and you could also modify the curve from the BFM ... It was valuable in a tiled room I had with a lots of windows. Heat gain with the sun -- colder at night.

I'm trying to understand how best to set this up ... having a way to keep the heat off would be nice w/o going to the boiler.

GW

Tag I’m not sure you fully understand, you can use a basic thermostat, kicks on the boiler which will follow a heating curve that you set. Or, skip the outdoor reset and let it bang on high fire.

TAG

I want to use the ODR.

I'm trying to understand what the optional fancy room control does -- the one that goes with the boiler? What f=do I get for $300.

And -- can I use the boiler w/o?

Sounds like if I go with the basic thermostat it will be an on off switch the way I want to use it -- or a limit. So if I have the heating curve set and I have the room thermostat above the desired room temp -- the boiler will follow the curve. I will keep running becsue the curve will keep the room under the thermostat set temp. If I go on vacation -- I could turn down the thermostat and the boiler will be turned off when the room hits that temp. May be useful.

gennady

Viessmann remote controls are just remote controls. You don’t need to go to boiler to make changes.
Thermostat can be used with viessmann if you connect it to boiler internal extention EA1 contacts DE1 then In service level 2 set address
3A:2,
3F:2,
9B: desired heating circuit water temperature in Celsius,

It disables boiler logic and maintains desired room temperature when contacts DE1 are made through thermostat. You will make smart boiler dumb.

GW

Semi dumb, you can still have outdoor reset

gennady

GW said:

Semi dumb, you can still have outdoor reset

Nope. No outdoor reset. Boiler switches to set point temperature instead of outdoor reset temperature.
To use outdoor reset with thermostat as a limit, thermostat should control system pump or zone valve, not a boiler, but setbacks must be disabled and thermostat setting better be higher than outdoor reset curve. Then, why bother? Better install remote and tweak curve.

GW

Disagree 😄 they certainly can to reset with DE input. You set the slope and shift

Obviously not “constant circulation” though

Paul Pollets

I always use the Vitotrol 300 and enable the internal sensor. On a very few occasions had to disable the sensor as the home worked better on pure outdoor reset. It seems kind of a waste not to use the advanced boiler control to its max ability. When the system is correctly dialed in, it holds setpoint to within 1 or 2 degrees. Conventional thermostats are not recommended.

TAG

Thanks: So the Vitotrol is totally optional -- doing about what the similar control does on my old Buderus setups. Correct?

I want to make use of all the Viessmann boiler's advanced features -- ODR w/ constant circulation.

There does not seem to be any -- remote/ cloud based control?

Due to my work. I'm in the city much of the time -- Does the 300 Vitotrol have a setback or "on/off" button? Having someway to adjust the system from a remote location would be great ... even to just turn it on and off in the spring and fall. I'm often not there for weeks at a time -- so turning it on prior to arrival would be ideal.

That's why when I saw the thermostat possibility -- I was thinking maybe it could be an on;off switch .. or maybe high limit. But - I don't want to give up features.

With the Buderus: one system with the room BFM -- I hit the setback button when I leave and it shifts to a lower curve. The other system I go to the boiler and turn down the two curve dials on both primary and secondary curves. It looks like with the Viessmann you have to enter the program control ... not as easy.

This is the old Buderus

Paul Pollets

Here's a link to the control...The internal sensor can be configured to work with either heating circuit 1 or heating circuit 2 (mixing valve) or heating circuit 3 (additional mixing valve)

https://www.viessmann.ca/content/dam/vi-brands/CA/pdfs/doc/vitotrol/vitotrol_300a_oi.pdf/_jcr_content/renditions/original.media_file.inline.file/vitotrol_300a_oi.pdf

TAG

Paul: Thanks -- better information than what I found. Think I better plan on them installing. The override will be worthwhile and make it easier to reduce the temp in the house when it's unoccupied. I will say Viessmann has pricing power!

Paul Pollets

Use shielded thermostat wire when installing these stats. 18/3 will give you an extra lead.