Vitodens 222F Cabinet Combi

Paul Pollets

I like the 222F Combi. It works well with homes that have a lower DHW load. This system has 2 temperature zones, the Main floor is a staple-up with plates, the basement will use 4 wall panel rads and a radiant floor in the new bath.

EzzyT

Nice clean job as always @Paul Pollets

hot_rod

Nice work Paul. How do you define a lower DHW load?

Like the Autofill

Paul Pollets

Less than 3 baths and no more than 5 residents.

SWEI

The 222-F is really a neat unit. Wish we had better Viessmann support down here.

njtommy

Nice job. I was just looking at them for a boiler replacement at a buddies house. Thinking of combi or the viessmann vitocrossal 300 cu3a. More then likely the vitocrossal will be the best bet.

Paul Pollets

the Vitocrossal does not have a built-in water tank. It does have larger BTU outputs, when needed.

hot_rod

Paul Pollets said:

the Vitocrossal does not have a built-in water tank. It does have larger BTU outputs, when needed.

Do they show a gpm rate at temperature rise, like the tankless units do? I've found 120K is inadequate. 130K combis work with a single draw at a time, my mother in law has a Laars/ Baxi combo and has learned to live with it.

What is the high fire output when DHW calls?
Keep in mind winter water ° in much of the NE and upper midwest is as lows as 35°F

I don't think "less than 3 baths or 5 residences" is a good way to market them?

Paul Pollets

I don't market them. I've installed 6 of them so far and the clients never run out of hot water. I'm not into "guessing" the flow rate or recovery rate. I also ask the customer how many teen age daughters he has...
The 222F-35 has a 60gpm peak flow or continous 3.3gpm flowrate based on 50-120 rise. The 222F will high fire at 176 for DHW production. It's the 26.5g storage tank that makes the difference.
http://www.viessmann.ca/content/dam/vi-brands/CA/pdfs/wall-mount/vitodens_222-b2tb_tdm.pdf/_jcr_content/renditions/original.media_file.inline.file/vitodens_222-b2tb_tdm.pdf

CarlosRC

Building New House and seaparate studio. Looking to install Vitodens 222-F 35. Four radiant floor zones, three in House, one in Studio.

Looking for help from someone who is very familiar with Vitodens 222-F installation options.

Have read manual and application guide, seem to be a few options for configuration, but not enough information to make informed decision on how simple or sophisticated to go with controllers and mixing valves and zone pumps. The Application Guide shows simplified configurations from those shown on the Technical Data Manual, not clear which is most efficient for our application.

Paul Pollets

It all depends upon what water temps are required. If you've done a heat loss on a radiant software application, it will tell you what's required. Embedded PEX methods use lower water temps, plated staple-up requires higher temps. If the design temps are within 10 degrees, you can use one mixed temperature, and balance the system at the manifolds. A mixing valve is required if you need more than 1 temperature. So is the low loss header.

CarlosRC

Thanks for quick reply! This is very helpful. Seems our application does not need mixing valves as only have one design supply temperature. Our four zones are all embedded PEX in 4" concrete slab on grade, same supply temp to all zones. Will the low loss header be useful to separate primary from secondary circuits and/or maintain lowest possible return temp to Boiler? Not sure what you mean by "..if design temps within 10 degrees you can use one mixed temperature..." , does this refer to using a mixing valve or a LLH? I may be losing something in the translation, but hopefully getting most of it right.

NYplumber

They're nice units and well made. Unfortunately the replacement parts and overall support from the factory turned me away. Thats after I have installed quiet a few Viessmann boilers. Tech support was a real bummer too. The rep was great!

NTI got my business.

Paul Pollets

The wholesaler needs to stock repair parts. Haven't had a problem with tech services. You should voice your concerns with both the local rep and the US VP (Mr. Lutz)
The LLH is required with the flow rates being used (CarlosRC). If all the zones are the same application (i.e. embedded) a mixing valve isn't needed.

CarlosRC

Awesome! If I may ask a couple more questions: 1- regarding valved versus pumped zones; don't have the design flows on hand, but looking at as built zone areas from 360SF to 700SF, the smallest zone closest to the Mech.Room, the largest zone is the farthest away on separate Studio building, second largest is in main House between the two smallest, think flow control will be critical as zones go on and off. Any thoughts on having either a variable speed pump and four zone valves or, a pump on each zone. 2- Do the Vitrotol controls with zone temperature feedback to Boiler provide any noticeable benefits, or in general, any suggestions on how best to control the zones.

Paul Pollets

The boiler knows what temps to make. I rarely use zone valves and a variable speed pump, but take advantage of the "continuous circulation" and zone by telestats at the radiant manifold, when required.Usually, I install a Vitotrol 200 or 300 thermostat, which provide feedback to the boiler control.

CarlosRC

Thanks again. Telestats are new to me. In fact heating is new to me, borned and raised in tropical climate. Been communicating thru intermediarie to heating system designer. Will be meeting designer Tuesday. No mention of Telestats, just zone valves or zone pumps. Obviously I have a relatively simple design, and different designers / installers have their own preferred way of doing things. I like to learn as muc as I can about how things work, learn what the different options are, and choose what seems best to me. I can't thank you enough for the insightful and to the point answers you have provided. Will do more research and continue to learn.

CarlosRC

I couldn't find much information on telestats. But, been getting a better understanding of heating system dynamics between primary/secondary circuits. So, seems The Vitodens will use temp feedback from LLH to set supply temp., so "boiler will know what temps to make". Also, seems with piping already built into our new floors, I'm getting Into the design aspects of our new House's heating system a bit late! It all started with getting what seemed conflicting information from General Contractor and Sub Contractor. But, it's all getting cleared up, and now that I got interested, I'll be meeting with the designer. At this point, any decision making left to do is on setup at the Mech room. Our designer had suggested zoning by valves, and in response to my inquiries, also suggested zoning by pumps. You seem to have suggested a third option, "continuous circulation and zone by telestats". I'm interested in clarifying and learning more about all options. If you can provide more detail or any links to more Information I'd greatly appreciate it!

Long story, no need to read it! It's about recent learning experience relevant to my newfound interest in heating systems design and operation. We are currently going thru second winter in temporary Home while we build. The 20 yr old boiler was replaced at end of last winter with a Navien NCB 240. Very noticeable improvement in comfort, will see how much improvement in reduced gas consumption at end of winter. The current House has two zones, all embedded piping, an old section about 20 yrs old has one (1) Honeywell zone valve and two circuits or sub-zones, and a new section about 3 yrs old has a second Honeywell zone valve and a single circuit. There is one new Grundfos UPS 15-58 three speed circulating pump for the zones, new globe valves and Temperature Gauge at each of three return circuits. Have used the return globe valves (possibly not the best for balancing) to "balance" return temps; one of the old circuits was returning much higher temps than any other no matter the pump speed, as much as 15-20°F higher. But also recently noticed, that even at max circ. pump speed and all valves fully open, the return temp. at the Boiler was always at least 15°F higher than the zone return temps. Also noticed that delta-T's at zones were at best 38-43°F (Boiler supply temp 138°F and zone returns averaging around 95°F). Don't want to make this post any longer. Will be talking to plumber who installed the system about possibility of making any improvements, which at this point are limited to a combination of increasing flow thru zones; And/or increasing supply temp from Boiler, especially on the very cold mornings when Boiler seems to struggle to overcome any and all inefficiencies in the old House's Insulation and embedded piping (adding outdoor reset may help in this regard). Perhaps there isn't much to be gained at the Boiler, and more to be gained from improvements in insulation, windows, doors...but as a temporary tenant I can only consider low cost improvements at the Boiler for one more winter.

Paul Pollets

Here's the thesis describing the process. It was written before modulating wall-hung boilers were available:
http://www.comfortableheat.net/pdfs/continuous.pdf

CarlosRC

Thanks for the link. I like the idea! I guess it's not something that is being done much or at all around here, but sounds like a great application for our design with the Vitodens Boiler. I will look into it and see what I find in terms of manufacturers and equipment. I hate to keep asking you for more information, but whatever you can add within the limitations of this blog is always welcomed. Thanks a lot again !

Alan (California Radiant) Forbes

Tell me if I'm wrong: Bell & Gossett coined the name Telestat for their zone valve. So when Paul says he's zoning with telestats, it means he's using zone valves.

So, there are two ways to zone hydronic systems:
1) zone valves
2) pumps

CarlosRC

Can't say you're wrong Alan. Below is an example of what a newcomer has to decipher when trying to figure out the details. From blog titled Taco Zone Controls and Telestats, I read one response and I get what seem to be good detailed specs, then I read a follow up response that says: "What is described is sub zoning on a manifold. Easily done with 1 manifold, actuators and alpha pump. Loving a Grundfos fixed velocity pump while sub-zoning with actuators would be the lesser choice in this application." http://www.greenbuildingtalk.com/Forums/tabid/53/aff/12/aft/82626/afv/topic/Default.aspx

The devil is in the details, is it not?

After meeting with our Contractor and the Viessman reseller in our area: Continuous flow is not something they are used to doing; they understand what it's about, basically zone valves with a mixing valve or loop back to the zones to maintain flow. In the end, I'll go with what they know how to do, and in our case I prefer that it be zone pumps. Experience living in the House will tell if it's worth making any changes in the future. Had I known what I know now, I would have been involved in the design from the beginning and perhaps would do things different.

CarlosRC

Paul, I was told yesterday that I can only have one Vitotrol 300 or 200 communicating back to the Vitodens. I think I read somewhere that there can be one Vitotrol 200 in each zone, connected in series back to Vitodens. It sounds like the Vitodens can take advantage of temperature feedback from the zones, but can it work with multiple zones ? Perhaps one 300 receiving signal from the 200's and relaying to the Vitodens ?

Alan (California Radiant) Forbes

Yes, very confusing, indeed.

About what you quoted: Telestats, zone valves, actuators: They are all the same thing. People use them interchangeably and you always need a pump to circulate the water.

I am a fan of Viessmann products. Take a look at their piping diagrams in their installation manual. If you are concerned with micro-zoning, install a low-loss header. Install it anyway. It's good ju-ju.

You probably already know that a Viessmann boiler will turn on when the outside temperature drops below 68° whether or not any zones are calling for heat which is another good reason to install a low-loss header so that the water has somewhere to go.

Simply Rad

Continuous circulation is the art of comfort and efficiency. It has amazed me for years. There are a few ways to do it as Paul has explained his method using the Vitotronic 200 or 300. To better understand...lets say the home has 3 levels. One would install a Vitotronic control for each level. Each Vitotronic is then coupled with a Viessmann mixing valve. The Vitotronic provide indoor feed back to the mixing valve and boiler. I have had great success with using what I call comfort dials, which are Oventrop non electric wall mounted thermostats. These are basically TRVs only with a wall mounted dial combined with a 6',15' or 33' capillary tube to reach my control valve on my manifold.

http://www.oventrop-us.com/catalog/pc/viewCategories.asp?idCategory=6

I used a variable speed pump and let er run. I also set up the system with no thermostats and use the ODR to dial in the lowest supply temp to keep the highest heatloss zone at 68F. The comfort dial them mouduate the flow and wahlah....the art of comfort and efficiency. I have this control system coupled with Warmboard and its truly amazing. I have a bout 100 systems like this ranging from 900ft2-18,000 ft2. Everything is modulating from my zone comfort dials flow rate, to the variable speed pump, to the ODR system temps, and the boiler gas modulation. As for the" Triple Deuce"(222) I have 5 units out there over the last 2 yrs and they ROCK. very clean neat and tight. I included a pic of an install from last year. I think of Viessmann boilers as appliances. Above the unit is an access panel to the piping.

Lastly, I would like to talk about the Vitocrossal boilers. I installed a CU3A unit on a 8000fts house this fall. The unit is also AMAZING. The fact that the boiler contains 20 gallons of system fluid storage helps alot with short cycling. The boiler modulates from 43K-199K. Without this storage even an 8000ftf2 house load on the shoulder seasons would cause the unit to short cycle, but the 20 gallon storage helps. Also, the unit has extremely low pressure drop through the HX so therefore I used only one pump for both the system and boiler. This also produces highers boiler efficiency with direct system fluid return to the boiler(no mixing). Also, this is simpler because I am not using a LLH and an additional pump for either the system or boiler. Also, the unit is ridiculously quiet.

CarlosRC

Thank you Paul, Alan, and Simply Rad for helping me navigate the sea of confusion that is heating systems terminology and applications. Would have liked to have one of you in our design team from the beginning, but, can't always get what you want...

I have narrowed down to two choices for our two building, piped as four zones, new House and Studio. Total heated area of 2160 SF. The Boiler will be the Vitodens 222-F 35, with LLH. Zone controls will be either four pumped zones, or two zones with mixing valves. I like the idea of a continuous flow system with the Boiler and mixing valves taking care of adjusting supply temps to zones. I think the House (1460 SF, 2BR/2BA) can function well as one zone due to its open design and all spaces being subject to similar solar gain. The Studio (700 SF, 1BA) is also an open space, but will be subject to different solar gain and use than the House, full time Artist Studio, part time Guest House.

For the two zone mixing valve setup, I think the Vitotrol 300 or other can be located in House's Great Room, optionally take input from Vitotrol 200's or others at BR's, and communicate with mixing valve. At the Studio one Vitotrol 200 or other can communicate to its mixing valve.

Simply Rad

If you are using the mixing valve concept, I would recommend that you loop each room separately and use a manifold that you can control the flows with a simple adjustment. You can then fine tune the zone with micro adjustments at the manifold with a flow adjustment. This is one example of a manifold I use

http://www.caleffi.com/sites/default/files/styles/product_photo/public/file/6687E5S1.jpg?itok=TsQYh_0c

CarlosRC

That's what I had in mind, each room looped separately and a flow control valve at each loop. Thanks for the link to the manifold.

Let's be clear, Our contractor did a rule of thumb type design and I didn't catch it until the tubing had been laid out and concrete poured. I saw the entire process trusting there was a solid design behind it, at least I know by sight the job itself wasn't poorly done. I am now doing a reverse engineering project with only the zone control options left to select. I received heat load calculations per room from equipment supplier, they were done after the fact. Will be getting as built piping layout from plumber. For now, I know there's one loop per room (zone), spacing is closer near exterior walls going to no more than 12" towards center. As evidenced by two in wall PEX headers, the two zones farthest from Boiler were split in two and three circuits. I'll get loop lengths from plumber and with that and heat loads "reverse engineer" head and flow calculations. I still think (gut feeling) that the mixing valve approach with balancing valves at manifold will work best for the three zones at the House; the separate Studio zone could be added be added as fourth zone, but I may give myself more flexibility at reasonable cost by treating it as separate temperature zone with its own mixing valve.