Boiler Buddy?

BBAA

Does anyone out there think it prudent to install a boiler buddy (or equivalent) into a conventional hydronic 3 zone system (3 floors, 1 zone/floor), the goal being to increase efficiency?  Current setup = Ultimate PFO3T oil-fired boiler, bottom two floors use CI radiators, top floor finned copper baseboard, total square footage being heated = 3300, no floor radiant heat.   Boiler does not supply DHW, each floor has its own electric water heater.  Already insulated supply & return piping, installed automatic vent damper & Heat Timer outdoor reset which have all helped reduce cost of operation.  Increasing/upgrading  existing building insulation from blown cellulose to foam (an ongoing project) has obviously helped as well. 



I realize there is a point where increased efficiency isn't worth the extra cost and the addition of a holding tank or boiler buddy may fall into that category, thus the request for your opinion.  Any other advice to increase efficiency would be most welcome.  Thanks in advance for suggestions!

crazy907ak

I would think so

but it depends on how bad your short cycling is i would think



Ive been doing allot of research lately into this problem for myself. Their is a few good research papers concerning the efficiencies that can be reclaimed from your boiler not short cycling if that is in fact why you would want a buffer tank. One i recently read is www.heatinghelp.com/files/posts/8258/BufferringKPWhitePaper.pd

hope that link works other wise just google "double digit saving buffer tank"

that will take you there.

long read but basically states improvement of 15% or greater.



am interested in how your automatic vent damper did by itself?



I bought one myself and had it installed by a local heating specialist but he messed it up

so now I'm waiting for its replacement. Hence thats why i'm doing my own research now

BBAA

Boiler Buddy

I'll check out that link, thank you.  If I could get a 15% increase in efficiency it would be worth the cost of installing a buffer tank. 



As far as the oil vent damper is concerned, I wanted to give it a try because my boiler has a fresh air intake, it does not pull combustion air from inside the building.  So in cold weather I was getting a constant cold air flow through the boiler & up the chimney when the boiler was off, which I figured couldn't possibly be good!  We haven't had a particularly cold winter this year in NH so it is difficult to give a fair comparison, but it certainly seems to me the boiler does a lot less short-cycling than it used to.  In fact, this is the first year I've been able to make it until January on one tank of oil (275 gallons) which pleases me greatly! Problem is there are other factors to be considered, i.e. I completed the insulation of the basement with spray foam this past fall.  (Did you know you can lose 1 million BTUs/day through uninsulated concrete basement walls?)  Field Controls says installing their automatic oil vent damper gives a 2-3% AFUE increase. I would say in my case it is at least that, but I'm afraid my estimate isn't very scientific.  In any case I figure every little bit helps.  I installed mine myself--don't trust installers!  I have had one "nuisance" lockout during very windy weather about 2 weeks ago, probably got a puffback down the chimney and it tripped the thermal safety.  Easy fix; just hit the thermal reset button. Other than that no problems so far!   Curious to know how your local heating specialist screwed it up, there isn't all that much to screw up on those things unless he/she miswired it or bent it out of round when it was installed.

SWEI

buffer tank

An electric tank-type water heater is the least expensive buffer you can get.  If you want maximum comfort and efficiency, install an outdoor reset controlled motorized mixing valve on the distribution side and run that on constant circulation.

crazy907ak

You wouldn't believe it

First off installer wired it in reverse polarity even though it says not to on almost every page !

And then i noticed he used the wrong wire for the burner control only to track the other wire had been jumped with a wire he ran down into burners control box where it was wired to the same wire!! The OVD was only getting one message to be on during boiler on and when it was off to be on. The guy was a moron! I have tried calling him but he wont call me back, go figure.

BBAA

Boiler Buddy/ Buffer Tank

Thanks Mr. SWEI and crazy907ek for your posts.  I have sent a separate reply to Mr. SWEI. 



As for the problem you (crazy907ek) had with the "technician", do you really want him to call you back??  He's trying to do you a favor!  It would seem there is a crying need for you to locate a new--competent--technician.  OR do what I did--do it yourself.  The OVD (Oil Vent Damper) is not that difficult to install, mine is wired to a Honeywell 7184U primary/Honeywell 8151A aquastat, the OVD wires in between the two.  Specifically, OVD orange wire goes to Aquastat B1,OVD yellow goes to red limit on the primary, OVD black & white go to Aquastat L1 & L2 terminals respectively, OVD green is wired to ground.  This ensures the boiler can't fire unless the damper is open.  And you're right, it says throughout the directions to be certain of the wiring polarity.  I don't know your setup, but if you can determine that you should be ok.  If you have questions you can also call Field Controls tech support, which I did prior to installation just to verify my wiring after I had figured it out.  The other thing they caution the installer about is making sure you don't squash the OVD out-of-round when you install it in the flue pipe, and be sure to observe the suggested placement of the MOV thermal safety switch.  Both can give you nuisance lockouts.  It's all there in the directions.   Sorry to hear of your misfortune, hopefully this will help. 

crazy907ak

Tech guy

Pretty much ran out, left one of his tools behind too. I figured out what the right way to wire the OVD right after he left but it was to late damage done, now i have to wait 6 weeks for an exchanged replacement. I have no problem doing stuff myself usually doing my homework first then after i feel comfortable enough i tackle it. Oil boilers are still new to me so i thought it would have been nice to help someone and get some infield training so to speak but i guess i just gained an experience .



There is some very competent installers in my town but they are a bit out of my price range at the moment though, i will be using their company for the next tune-up so i can pick their brain while they are working though.