Viessman Vitola 200-DHW but no radiant heat

Roytreellc

Hey Folks,  I apologize in advance if this has been covered before, but I searched the topic and couldn't find anything.



I have a viessmann vitola gas boiler (circa 2001) that has performed flawlessly up until now. My house is roughly 1700 square feet and is heated with staple-up heat tubing on the main floor and in the basement slab. Each floor has 5 zones a piece and uponer valves to control them.



Like I said, it all worked flawlessly until today, I walked into the house and it was cold. When I checked out the boiler it appeared to be normal. The control panel showed the boiler temp at 160 degrees, as normal and was still set on the "heat/hot water" program, like normal. The hot water is working fine, as always.



Looking further, both of the heat supply manifolds are cold. The grundfos circulator on the back of the boiler supplying them is also cold, so cold that both the supply and return temp. guages aren't even registering. I put my ear against the circulator and it appears to be circulating, cold water. The uponer valves on the heat manifolds are responding to a call for heat from their respective thermostats, but all they are getting is cold water.



Feel free to ask any questions to clarify, i'm not a boiler man but I understand the basic principles of the system.



Thanks in advance!



Josh

Ironman

Your Ear...

May be deceiving you.



If you have 160* at the boiler and it's cold at the supply manifold, then it's not circulating water. Whether it's a bad circ, air bound or something other will have to be pin-pointed.



Post some pics of the boiler and its piping would be helpful.

Roytreellc

It may be

Hi bob, thank you for the quick reply, here's a few pics of the operation. Don't mind the clutter!

Ironman

Circ

You have another circ (the red one) that appears to be your radiant circulator. That may not be pumping.



I'm not familiar with the details of the mixing block at the boiler or the specifics of the Viessmann control. Maybe one of the Viessmann guys on here can help, but you may have to get a pro to your house.



Looking at the pex tubing near your manifolds: is that "AquaPex"? If it is, then it's not o2 barrier and that could cause pump and eventually boiler failure. Look to see if has a brand name or "oxygen barrier" on it. The cast iron components of your system cannot withstand oxygenated water.

Paul Pollets

Questions

You have a Divicon pump module on the boiler. The Divicon has a motorized actuator. You have a Viessmann 4 way mixing valve without a motor actuator or a pump. Why? The heating circuit will have a hard time getting warm with out a pump on the mixing valve supply. You'll need a pro with Viessmann experience to help you with this. If the tubing does not have an 02 barrier, the system will not last long.

Ironman

Paul

I was wondering about the reasoning behind the manual 4 way also. If the radiant is in slab, I don't see how it could properly regulate the slab temp.

Roytreellc

I think it may be....

Airbound... The circulator on the back of the boiler is working, I can hear/feel it working. That mixing block on the rear of the boiler serves only the upstairs side of the system and doesn't work by way of the 4-way valve. That block is the only path for the upstairs side of the system, one feed and one return back to the block. The four way only serves the basement slab side of the system, which is also the red grunfos circulator that you can see in the pictures. The basement side of the system is working flawlessly, I am getting a pipe temp of 90-95 degrees on the supply side and good response on the return side of the manifold.



The main floor side if the system is showing only 70 degrees on both the supple and return at the block on the back of the boiler. It seems like something isn't letting the heated water into the system for the upstairs side. I definitely heard some air movement tonight through that zone when I got home and cranked the thermostats to load the system, I'm gonna hit the bleed points and see what happens.



Also, the tubing run throughout the house is Wirsbo HEpex tubing, not sure if it's O2 barrier of not but I am going to do my research.



I appreciate the help thus far, please keep it coming



-Josh

Paul Pollets

Mixing Valve

The 4 way won't do well without the motor actuator & #2 sensor. Someone didn't understand the design & equipment requirements when installing this system. Viessmann prefers constant circulation with their systems...telestats are to be used sparingly, not on every port.

At least there is barrier PEX.

Weezbo

Howdy ,

Habby Thanksgiving ,

is there an additional header in a closet or behind an inspection panel , or maybe under a stairway on your floor with low temp ?



have you tried say, closing the blue handle valve a couple times , to see if the needle on the temp gauge bounced or moved ?



does the pressure gauge say one bar ?



Weezbo.

Weezbo

oh now i remember...

did you check your Circ with the little Grundfoss spinny tool?



Way more reliable gizmo ...



*~//:)

it is one of those tools that seems to be able to hang in with me for whatever the reason ... comes with "Operation instructions lol..



if the blue handle side is in the 2 oclock position i think it would give some indication on one of the two gauges ...

Roytreellc

Airbound

Thank you guys for all the responses. It seems like the system has air in it. Does the silver thumb screw on the top right side of the manifold shown in the picture act as an air purge? Or do these systems typically have a way of bleeding themselves out? I can hear the circulator on the divicon block chewing on some air but it's still pushing. Unfortunately the supply temperature is still way too low. Even with all the zones calling for heat, it still isn't giving heat.



I have a friend/acquaintance who is a plumber with viessmann experience so I may have to call on him to look at it. I have a feeling it's more than just some air bubbles. Will the air going through the boiler cause trouble? It may be a few days before I can gget him over here. I have 2 wood stoves in the house so heat won't be an issue if I have to shut it down for a bit.



Thanks again for the help,

Josh

Roytreellc

weezbo

I tried closing the blue valve a few times with no reaction from either temp guages.



I can't seem to locate another header anywhere in the house, the system is centrally located and it seems all the pex goes directly from the manifolds out to their respective zones.



Unfortunately I don't possess a grundfos spinny tool, I think it's time for a pro to come in.