Is ISeries the right choice?

cheftim_2

With a lot of help from you all here, I installed a new Buderus oil fired system with one floor of radiant and one floor of baseboard few years back. I have the Buderus controller as well so the radiant floor is in continuous circulation with outdoor reset. All works well.



I've done some remodeling and ended up changing the second level to radiant as well. Since the Buderus can't control two separate radiant loops with separate temps, I installed a Taco ISeries to do the mixing for the second floor. It has outdoor reset as well. Here's where I went wrong. I put a regular tstat controlling the power to the upstairs loop. I was wrongly thinking this was going to work like the first floor which has the Buderus BFU in the living room. This new loop obviously isn't running in continuous circulation.



I'm figuring I can remove the tstat from the upstairs loop and piggy back the power for the circulator and ISeries off the circulator for the first floor radiant loop. My thinking is that once the first floor is in heat mode, that will put the second floor in heat mode as well and then I can set the ISeries appropriately to handle the load.



What I don't like about this approach is there's no feedback from the upstairs like in the first floor with the BFU. Is there a different controller that can accomplish this or should I just let the ISeries do it's thing?

cheftim_2

Anybody?

bump

Mark Eatherton

Tough call...

If the rooms had nearly identical heat losses, which I doubt they do, or you would have just added the 2nd floor to the first floor package, it MIGHT work.



You could add a non electric TRV to the second floor to control over temp conditions.



That might require that you add a pressure differential valve to the package serving floor 2 to avoid dead heading a pump, however, it has been my experience that 2nd floors always lose more heat than do 1st floors, unless there is a significantly different foot print between the two floors.



They make remote capillary tubes up to 10 meters long for these puppies.



Best o' luck.



ME

Hydro

Buderus Radiant

When you say you have the "Buderus control" does that mean a Logimatic R2107? with a FM241 module controlling the radiant temp. through a motorized mixing valve? and why does the other radiant zone have to be another temp?

CMadatMe

If Your Interested

You may want to think about changing it out to something like the attached. It's may cost you a few bucks but in the long run may give you what you are looking for. You could temporarily get the existing up and running for the rest of the heat season and plan on this for the next.

cheftim_2

Here's my setup

Thanks for the responses folks. I looked at the Vito but it doesn't appear to be able to run two separate radiant zones. Maybe I'm missing something. Plus, I've a bit of money already in the 2107



First Floor



Install:

Retro using thick gauge aluminum plates under floor

900 sq ft brand new ceramic tile

350 sq ft Bamboo flooring



Temp Control:

RS2107 with FM241 card, Buderus 3-way mixer, outdoor reset module, BFU indoor sensor, appropriate heating curve in 2107



Flow Control:

FM 241 using warm weather shut down controlling circulator in constant flow when on as well as mixing valve



Pros:

Wife is happy

Man I love radiant under ceramic flooring

Get feedback from the zone with the BFU

Can override auto op and set the desired temp via BFU

System only sips fuel



Cons:

None yet



Second Floor



Install:

Had the ceilings down for some remodel so did same heavy gauge aluminum under flooring

Some radiant wall in a section where I didn't remove ceiling below (thanks to Mark for convincing me this is such a great approach)

New Berber carpet, some linoleum, some Cork flooring



Temp Control:

Taco iSeries motorized/intelligent 3-way mixing valve, outdoor reset module, appropriate heating curve settings in iSeries via dip switches/roto switch



Flow Control:

Wired in parallel to the circulator for the first floor. This approach puts the circulator in constant flow when the 2107 goes below the WWSD target so both the first and second floors are in constant flow/temperature modulation when needed.



Pros:

Now that this floor is in constant flow, the wife is happy.

Radiant wall works like charm.



Cons:

I miss the ability to override and tweak the upstairs level via an indoor control as with the first floor BFU sensor. I suppose if I have my iSeries set correctly, it shouldn't really matter, but, I like control.



So, at the end of the day, I'm really just looking for a way to get some room level control over the system when desired.

cheftim_2

Because of the BFU

Hey Hydro,



The BFU indoor sensor is on the first floor providing feedback about that zone. The second floor may end up too hot or too cool because of that. Yes, I have the 2107. FM241, and Buderus 3-way motorized mixer in constant circulation.

Hydro

Buderus Radiant

The 2107 is not really a thermostat its usually installed in the common area of the home (the place where the family hangs out the most)  thats one of the places it will take information back to the 2107, its main job is to control the 2107 from a remote location, and to override the program that you have set it to, like when its in night mode, in which it sutracts 3-5 deg.from your day temp setting, and its a holiday, you stay up later than normal and you want the heat to stay on till 11pm instead of 9pm. you override the 2107 from the room sensor. you can still use a thermostat on the zone, and the boiler will still function the same, with a multi pump relay, and conventional t-stat. you can install a second room controller (or room sensor) one is on the 241 module and one on the 2107, both are marked bf brown on the circut boards. then you could have lowered the temp in circut 1 via the programing, as circut 2 is the 241 module, then manually mix the zone if need be. My question is why do you need a second temp anyway? unless you have a large area of rug, just run it at a lower temp for the hardwood, tile etc, and put it all on circut 2, if not check your piping and switch setting on the I series valve, see.attch.

  

cheftim_2

Yeah, lots of rug

In the upstairs zone. The flrst floor is mostly tile with a bit of bamboo. The upstairs is 80% new berber and the rest cork, tile, linoleum. Besides, I like the upstairs to be a bit cooler than the main living area. It might make sense to just run it off the downstairs loop and it would probably have ended up a bit cooler anyways. May have over thought it, just wanted to have some control. I'm a software developer by trade and have figured most of this out on my own with help from this board. Figured if I screwed up the calcs and what not, having a control device upstairs might compensate for getting yelled at if it's too cool. :-)



I believe the BFU room sensor also contributes to the control logic in the FM241 and is not just a simple override. I may be mistaken though.