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Direct vent oil fired boilers

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Hvac tech_2
Hvac tech_2 Member Posts: 21
Direct vent vs power vent and are the direct vent reliable when it's - 5 outside

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  • clammy
    clammy Member Posts: 3,113
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    From my past experences i ,ve only had a few direct vent boilers some burmhan and a few dunkirk and i will say that they where both very finkey to set and rid oneself from issues like sooting .From what i have seen one must be keen on proper installation not only with the flue and air intake but with the oil supply and boiler piping espically with the low mass boilers to hi mass and even boilers that are tightly sized .A few helpful points are use a tiger loop ,install the fresh air intake and use a pre and post relay with a oil delay valve and of course use a combustion anz to test.Also if it s a cold start and a large mass system make sure you install a by pass to warm that boiler up quick other wise you will end up with a issue espicqally with smaller sized boilers.As for power vents i have used a few tjerlund ss1 and have found alot less issues using them then with direct vent .I found it much easier to set the draft properly reguardless of out side factors .I have one thats been in a a burmham for over 14 years without any issues .There pretty quite and with the restriction baffle you can get the draft and stack down to the proper level.The zero clearance and fitting in a 16 in oc beam space is also a plus It s kinda sad that alot of newer homes are being built with no chimmeys and oil fired direct venters you look at the side of the house and it s black and usually they never install the fresh air duct work and have even extra issues being the house is new and as tight as a drum .If i was comtenplating oil and had no chimney i would be looking at a tjerlund ss1 or 2 .In the many years of oil service i did i ve rarely had a soot loaded boiler with them compared to the direct vent evn though the dir4ect vent is cheaper if the unit does not get serviced yearly you will be cleaning her on a late night service call i don t think soot sticks work well on them .Just my advice peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
    icesailor
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
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    I have had less than positive experiences with oil DV, of various brands and avoid them.
    icesailor
  • billtwocase
    billtwocase Member Posts: 2,385
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    Power vent over direct vent any day
    icesailorSuperTech
  • Hvac tech_2
    Hvac tech_2 Member Posts: 21
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    Is the direct vent a large diameter hole in the house then the powerventer may be my first direct vent install for oil always have powervented have a customer who wants direct in place of powerventer leaking boiler
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
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    Generally the same size hole give or take. Your question is garbled but I *think* that's what you're asking.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,542
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    A boiler built for direct venting would be my choice,rather than an existing design converted to DV by slathering the sections and cleanouts with RTV! Firebird and Peerless Pinnacle Oil are built from ground up for DV and although capable of chimney venting,the Buderus G125BE seems to DV quite well. Power venters are mechanical chimneys and will fail,sometimes at the worst moment!
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    icesailorZman
  • Jack
    Jack Member Posts: 1,047
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    Years ago, when the ASHRAE show was in Atlanta, my partner and I were the Tjernlund reps. All the folks from Tj and we had a meeting to discuss what a new product for oil PV would look like. It was great. Ordered in pizza and hammered out the SSII. The original hope for that product was that manuf would test it with their boilers/furnaces and certify them as a package and therefore be able to eliminate the barometric. The draft adjustment is very fine on the II and we figured it would really fill a need. It was that very year where all the manuf decided that direct venting with the burner was the hot set-up. Knowing what I know about sidewall venting I think you are asking a burner to do a lot over a long period in widely varying conditions. That is especially so when you consider how well folks maintain their equipment.
    kcopp
  • icesailor
    icesailor Member Posts: 7,265
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    @Jack:

    I didn't know your relationship with Tlund.

    In my case, where environmental conditions were so bad with high winds from any point of the compass, I decided that I preferred to use a SS-1 rather than a masonry chimney because I had so much more adjustment with the PV. I didn't like the SS-2 because with my high winds applications, the fan didn't have enough nuts to overcome direct, head on winds. Then, there were the applications. A WA furnace where they tried as hard as they could to get the exhaust directly under the PV'er, and to fork on them, you had to crawl up on top of the supply piping, if disconnect it.
  • Jack
    Jack Member Posts: 1,047
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    The thing about all side wall vented equipment is that it is tested to a 40 mph sustained wind. There were always those situations on the coast of Maine...and elsewhere, where it was necessary when a low pressure blew in to put something out ahead of the vent termination to break up that sustained or gusting pressure. The II has the material handling fan so it will shed the build up that the I will just hold in that curve blade wheel. So from a cleaning standpoint the II is just much better. It peaked at 1.25 gph.

    As long as I'm on PV's I have to say that a big part of the problem with them was that they were seldom serviced. I cannot tell you how many homeowner calls I would get and the guy would be asking for a new wheel for his PV. I would ask why he was looking for it rather than his oil company. To which they replied, "my oil company won't service PV's". I would then ask why they bought oil from them. The doctor says I will give you a physical but I don't do hearts and lungs:)
  • clammy
    clammy Member Posts: 3,113
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    I totally agree w jack .I have serviced direct vent oil boilers and every one had draft issues and all vented no more then 6 to 8 ft of pipe with maybe 2 elbows .Every one i worked on had no fresh air duct ran as suggested and every one was packed w soot.As many may say that they would rather put a dv instead of a power venter it seems to always be the heating /plumber who does not want to put the power venter but also they are never the ones who service the unit and if they are be prepared had one guy want to charge the HO like 6oo bucks to open and vacume it out and he stated that this is normal they had put the boiler in no more then 6 months earlier and the soot was not from making heat but hot water it was the summer.Changed the outside termantion and used the fresh air inlet and set her up and did a combustion azy throw on a tiger loop and that was that .I gave the HO up was about ! hr away and needed some major repiping low mass burmham and tight sizing they did not what to re pipe so i tossed them back to the sea who wants to have to clean something everycouple of months because the boiler is condensing upon start up and you know it goes out always at nite .The guy who installed it says it s normal i guess in that neighborhood the side of every house is black w soot and they all installed by the same guy his bussiness is right down the street ,they rarely do service but when they do they are heartless and do just about zippo .Do your HO a favor install the ss2 if not have them call a manson and do a chimney when they get that price that ss2 will look like a cheap bargain or have them price some all fuel stainless vent pipe have the paddles ready same applies for the masonary chimmey why u think the builder didn t have one speced because he put that coin in his pocket.As for the peerless hi eff there great but without proper set up and annaul cleaningby some one who will do the right thing that thing will be trash and a service nightmare .In the past i worked for oil co and did installs and 24 /7 service and nothing and i mean nothing is worse then having to clean and try to re set up a dv boiler say at 1 or 2 in the morn do a couple of those and u will understand reasoning for the power vent .peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • clammy
    clammy Member Posts: 3,113
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    On a side note ,key to service is proper installation and as some might know and guess that all things have a life span.I personally after 10 to 13 years on a power venter would want it completly serviced or replaced it s done alot of work at that point and as you know it will die onthe coldest nite of the year.Some may bauk at my thinking but put it this way that pv er is about 1 /16 of the cost of a real chimney that you do not have .And as funny as it seems alot of oil guys won t work on them and have no clue and carry no parts The last one i had to talk the guy through said it was to complcated told HO they need a real oil service co lol peace and good luck clammy PS at this point i very rarely do oil only for a chosen few
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • billtwocase
    billtwocase Member Posts: 2,385
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    We service them. I stock all the SWG motor assemblies, SS1 motor assembly, I won't mess with trying to replace just the blower wheel, never works out. Also stock fan provers, spillage switches, timer relays , brake line for prover tubes, and so on. All part of the job to me
    SWEI
  • RJMCTAFO
    RJMCTAFO Member Posts: 113
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    If you have to go DV we have had good luck with the Buderus/Riello combo. Have a lot of DV in our area and find just like anything else if installed and maintained properly they run well. Have 5 houses in a development that are all DV Utica SF3 boilers with AF2 burners. Have to put your hand on the connector to the vent to see if it fired they are so quiet.

    Only problem one is installed with the vent on the side of the house that faces a 300 acre corn field with nothing to block the wind. :/
  • Jack
    Jack Member Posts: 1,047
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    RJMCTAFO....ok man, what does that mean? Your cornfield story reminds me that selling pv's I would always make the statement that if X side of the house is the right location for the DV boiler, but the Y side is more convenient for the builder/homeowner, which side are 90% of the jobs going to end up on?

    Clammy, I look at masonry chimneys as 11th century technology venting 21st century appliances. Masonry is jus always oversized and the mass of the system is so great that you end up with issues. I don't have a problem with chimneys. I just think a factory built chimney is 5 times what a masonry flue is. I've had good luck with Pellet vent on liner systems for oil down to 4"...if everything else is right.

    Appendix E in 31 is spot on with sizing.
  • RJMCTAFO
    RJMCTAFO Member Posts: 113
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    RJM initials
    CT Connecticut
    AFO American Fuel Oil Name of my parents oil company. I am working for myself now so I need to change my handle.
  • clammy
    clammy Member Posts: 3,113
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    Jack in agreement with old chimney tech and the shabby work on alot of them .But the b vent in a outside built chase is allways in builders budget but try to get then to do a all fuel pipe for oil and there arms get short with the money .Every boiler has it s place including DV but i don t want to be the one servicing it at nite usually means a cleaning .I know other di slike them but when i worked for a oil co i never dis liked the af 2 i always had good luck w them while others i worked w hated them like the plauge .peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • icesailor
    icesailor Member Posts: 7,265
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    "B" vent is for Gas, not oil. B Vent has an aluminum inside. It needs to be stainless.

    "Contractors would insist on gas B-Vent for an oil application rather that all fuel because it is cheap.

    I think a lot of "contractors were born they the genetic cheap gene. A requirement of being a "contractor". Especially the ones that always haggle you over a price and then don't pay.

    JMO&E