Wouldn't Believe It If I Hadn't Seen It

CMadatMe

With my on eyes. Went to a job this morning at a contractor house where we put in the new Vitodens 200. This customer has installed alot of mod/cons but his house was his first Viessmann. a WB2B-26.  The house is all baseboard, 5 zones of it. He did put in some Suntemp 800 series in a couple of the zones the rest is basic residential board. It is zoned with zone valves and we used a Grundfos Alpha as our system pump.  The main zone also has a Vitorol 300. This morning it was 27 degree outside and the boiler water temp was 108 and on the system side of the low loss header was 98 degrees. 98 degree water was supplying this house and every single zone in the house was 70 degrees and comfortable. The boiler has been in for a month and he has yet seen any water temp above 120 degrees. The coldest it has gotten here to this point is 17 degrees or so. Has anyone else experienced this in this type of application? 



This has my brain asking the question. If I can design/do this in a baseboard application properly controlled with a Mod/Con is it a bigger bang for the buck for the customer than installing a complete radiant system? Is the money/efficiency savings for radiant truly any better than what is being experienced here?

Steve Ebels_3

B/B ratio

Low temp operation is all about the emitters and how well the building is wrapped. Obviously the customer isn't enjoying warm floors but hey....... some extra BB costs far less than Climate Panel or tube and plates. I say the Bang/Buck ratio is pretty good.  

CMadatMe

Warm Floors

Would have been nice to have some radiant but retro-fit job. My customer really wanted to see what he could do with the boiler on retrofit baseboard jobs. He does alot of replacment boilers in exisiting homes. The goal is to make the boiler  as affordable as possible with the best payback. He using his own house as a test case.

CMadatMe

Warm Floors

Would have been nice to have some radiant but retro-fit job. My customer really wanted to see what he could do with the boiler on retrofit baseboard jobs. He does alot of replacment boilers in exisiting homes. The goal is to make the boiler  as affordable as possible with the best payback. He using his own house as a test case.

Tom Blackwell_2

Temperature

As was previously said, it is up to the ratio of emitters vs heat loss. We did an old (1927) house 2 weeks ago using a mod-con with existing cast-iron radiators that were originally gravity. The house is 5,000 square feet with 12 foot ceilings and no insulation. The system was started up on a cold afternoon and that night the temp got down to 20 degrees with wind. The next morning the boiler had cycled off on room temp and the max temperature had been 145 degrees. I might add that the new boiler replaced a cast-iron atmospheric that was over twice it's size. Comfort has a lot to do with the areas our bodies are radiating TO, and the warm emitters give far more comfort than warm air. One of the reasons that radiant has gotten a bad rap in the past is that a lot of systems have been designed using 200 degree water in an effort to limit emitter cost-the result is uneven heating because of the high temperature output of the smaller emitters. The cooler the emitters are while handling the load the more efficient-and comfortable the system will be. The previously mentioned job was a fight, because several local contractors had "advised" the owner that warm air was more comfortable and more efficient. Luckily the owner was a friend of a friend.