Any Burnham Revolution Experts? I Need Advice

Discussion in 'Boiler Forum' started by lp20th, Sep 9, 2019.

  1. lp20th

    lp20th New Member

    Joined:
    Sep 9, 2019
    Location:
    New England
    I recently purchased a home that was built in 2003 and has an original, propane-fueled Burnham Revolution, Model RV5PSL-12 boiler. I am questioning its fuel consumption as it seems excessive to me and from what I have learned this system may have been installed incorrectly. According to the installation manual I have, the zone circulator pumps should be installed on the send side and they are not. The circulator pumps are on the return side, which is typical for most boilers. There apparently is interference with the internal variable speed mixing circulator having the zone circulators on the return side.

    In speaking with a few service companies I am getting conflicting answers. Some say it makes no difference at all, some say it makes very little difference some say they should be moved per the installation manual and efficiency will improve.

    Before I spend the money to move the curculator pumps I would like to get advice from an expert with these boilers. I reached out to US Boiler (Burnham) but they will not talk technical with a homeowner. I would like to to know if its worth doing given the age of the system . What would the efficiency improvement be in %, if any? Will I get a payback in fuel savings?

    The system runs good, has 3 heat zones plus an indirect domestic hot water heater however the baseboard radiators do take a long time to heat up , thus the system seems to run a long time when there is a call for heat. This is what led me to investigate this further.

    Thanks in advance for any advice you may have.
     
  2. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    The incorrect pumping may take a few percent off it's as-used efficiency. Instead of ~88% efficiency it's only running in the mid-80s (but not under 80%.)

    I suspect a bigger problem is that it's ridiculously oversized for your actual heating load, which means out-sized standby/idling losses (especially in the shoulder seasons.) Run a fuel-used based heat load calculation on wintertime fuel use only (when the solar gain and domestic hot water errors are lowest, and cancelling), which is a measurement of your actual heat load using the boiler as the measuring instrument. For calibrating the measurement assume nameplate efficiency, then derate by 5% to account for system design errors.

    There are almost NO houses in New England built in 2003 that needs a ~130,000 BTU/hr boiler except those larger than 6000 square feet of conditioned space, located on a mountain top in northern Maine. You may not even have the 200'+ baseboard (or other radiation) it takes to even emit the 100,000 - 110,000 BTU/hr of output that the RV5 delivers.

    Measure up the radiation zone by zone, and run the load numbers. Even if you stick with LP fuel you'll want to find something more appropriate than keep tweaking the system as-is. But without the load & radiation sizes it's hard to come up with an optimal solution.
     
  3. Sponsor

    Sponsor Paid Advertisement

     
  4. lp20th

    lp20th New Member

    Joined:
    Sep 9, 2019
    Location:
    New England
    Thank you Dana.

    No one has ever suggested boiler sizing as an issue. I will look into doing the heat load calculations. The propane is supplied through a community tank and is metered and billed monthly so I have some good monthly usage data.

    This house has about 3000 square feet of heated living space and is located in southern New Hampshire. What caught my attention this past wnter was that the house was not lived in full time so the t-stats were set to 58 most of the time. Maybe 6 days of a given month they were turned up to 65-68 degrees. My full time house in Northern Connecticut has an oil fired system and the heating cost was substantially less. I know it’s not comparing apples to apples but none the less the New Hampshire house seemed excessive to me considering the time-stats were lowered most of the time.

    One extra caveat; the main living space has a propane fueled heat-a-lator fireplace. This area is wide open with vaulted ceilings, around 1000 square feet of living space, and when it is used it will warm up this area nicely in the winter. In the latter part of the winter season I started to use it when I was there and it seemed to help keep costs down. It probably will mess up some of the calculations though.
     
  5. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    If it's set to 58F most of the time you'll have to use base 55F heating degree day data to come up the BTU/hr per degree-F slope, then add 10F degrees to the heating-degrees when multiplying it out. eg: If you're near Keene where the design temp is -3F, if 55F is the true balance point it would be 58F heating degrees, but to heat it to 68F the balance point would be nearer to 65F, so at -3F it would be 68F heating degrees x slope = implied load.

    Since the propane is billed monthly, narrow down the analysis to only months when it didn't get above 55F more than a couple of times (or not at all.)

    As a sanity check, typical heat loads of reasonably tight 3000' houses built in 2003 at -3F outdoors, 68F indoors would be 35000-40,000 BTU/hr, not much more unless it has a lot of windows or massive air leaks. If it comes in over 50K let's figure out why. Is there a basement under the 3000' of house (and if yes, how big?).

    Per MMBTU #2 oil is substantially less expensive than propane. A gallon of oil has 138,000 BTU/gallon (0.138MMBTU) whereas propane only has 91,600 BTU/gallon (0.0916), so even when the price per gallon is comparable the oil has 50% more energy content. If you don't already have central air it may be worth considering a couple of cold climate mini-split heat pumps, which can operate much more cheaply than propane boilers in most markets. A single 1.25 ton Fujitsu can deliver 18,500 BTU/hr into a 70F room when it's -5F out, and about 21,000 BTU/hr into a 55F room. (What are the electric rates, and how much are they billing you per gallon of propane?)
     
  6. lp20th

    lp20th New Member

    Joined:
    Sep 9, 2019
    Location:
    New England
    Thank you again Dana.

    To answer some of your questions and comment on your suggestions:

    The house has a main floor of 1825 sq ft finished living space. The lower level is a walk out basement with the perimeter walls being concrete half way up and framed the rest of the way up to the 1st floor deck. The finished living space in the basement is 1200 sq. Ft. and is all studded, insulated and sheet rocked. The remainder of the basement area consists of a 25 x 25 unheated garage at 625 sq ft and a small utility room where the boiler resides. The unheated garage is directly below finished living space. All wall framing in the house 2x6. I need to measure the feet of baseboard for each zone the next time I’m there. The 3 zones are the main living area at 1200 square ft, the area above the garage at 625 sq ft and the finished basement at 1200 sq ft. The house is about 25 miles northeast of Keene NH.

    Propane cost has been $1.999 a gallon this past year.
    Electric rates are currently: $.08825 KWHR (supplier charge) + $.09099 kWHR (delivery charge) = $.17924 KWHR

    Some data points for propane usage:
    November 2018 - 101.68 gallons, 3700 cu. ft. $203.26
    December 2018 - 109.92 gallons, 4000 cu. ft. $219.73
    January 2019 - 134.65 gallons, 4900 cu.ft. $269.75
    February 2019 - 112.57 gallons, 4100 cu. ft. $225.23
    March 2019 - 95.43 gallons, 3400 cu. ft. $186.77
    April 2019 - 52.31 gallons, 1900 cu. ft. $104.37
    May 2019 - 24.73 gallons, 900 cu. ft $49.44
    June 2019 - 5.5 gallons, 200 cu. ft. $10.99
    July 2019 - 13.74 gallons, 500 cu. ft. $27.47
    August 2019 0 8.24 gallons, 300 16.47

    just prior to purchasing the house last October I had a house inspection done. One observation that the inspector made upon testing the heating system was how long it was taking for each heat zone to get hot. The zones eventiually all did get hot but it did take a while. He observed that the zones were filled with antifreeze that had never been changed or serviced and suggested that maybe the antifreeze had coagulated overtime and is impeding flow. At his suggestion the homeowner agreed to have the system serviced and purged of all the antifreeze and refilled with water. This was done. The efficiency of the boiler was tested at that time and it came in at 87.9%

    Once the heating season began I noticed no improvement in the time it took a zone to get hot, thus my investigation began and I did find the info on the zone circulator pump location for this boiler.

    The house does not have central air and I am considering adding it as this house will eventually be becoming our primary and only house within a couple of years. The mini split heat pump is definetly a consideration.

    Sorry for the rambling but I wanted to get this info out to see if you see anything standing out.
     
  7. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    A quick & dirty cost comparison.

    Two buck propane at 88% efficiency is about $25/MMBTU. That's not counting the pumping or control electricity use.

    18 cent electricity at an HSPF of 11 (reasonable to expect from a typical mini-ducted mini-split with a cool climate compressor) means seasonally it averages 11 BTU/watt-hour, or 11,000 BTU/kwh , which works out to about $16/MMBTU. It's a real discount! A bigger air handler type central air might come in at an HSPF of 10, or about $17/MMBTU. Get the size right and you can sometimes beat the nameplate spec on efficiency.

    Some smaller ducted minisplits have even higher efficiency, and some ductless minisplits are in the 13s and 14s which is much higher. The 1.25 ton Fujitsu I linked to in the prior post is in the 13s, it's 3/4 ton baby sister tests in the 14s. The cold-climate Mitsubishi FH series & LG ductless mini-splits also test in the HSPF 12-14 range. Depending on the floor plan you could do part of it ductless, part of it ducted, making it easier to avoid having to run the ducts outside of the thermal and pressure boundary of the house.

    With a ZIP code I can find the nearest weather station on degreedays.net (or you can find it yourself) to run the fuel use load numbers on. Exact meter reading dates would be necessary to get this right.

    Is the boiler room insulated?

    How many feet of baseboard is there on each zone, zone by zone?
     
  8. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    Very crudely (large error without meter reading dates) the cumulative monthly base 55 HDD at the Dillant-Hopkins Airport in Keene for last December through February came to 2644 HDD55F.

    Over that time you used:

    December 2018 - 109.92 +
    January 2019 - 134.65 +
    February 2019 - 112.57 =

    357 gallons

    So that's 357 gallons/2644 HDD= 0.1350 gallons/HDD, which at 91,600 BTU/gallon is 12,366 BTU per degree day (source fuel BTU), which at 88% efficiency becomes 0.88 x 12,366 = 10,882 BTU per degree day delivered into the heating system. In a 24 hour day that becomes 10,882/24= 453 BTU per degree-hour.

    When it's 65-70F indoors the heating/cooling balance point becomes something between 60-65F, so lets use 65F to be a bit conservative. When it's 0F outside there are 65F - 0F= 65F heating-degrees, with an implied load of 65F x 453 BTU per degree-hour= 29,445 BTU/hr (which would imply a pretty tight, well insulated 3000' house if it were all above grade, which it isn't.) At -10F there would be 75 heating-degrees, and an implied load of 75F x 453 BTU per degree-hour= 33,975 BTU/hr.

    Your actual design temp (and load) is likely be between those numbers, but the error bars are large due to the distance to the weather station and the imprecise meter reading dates. Better precision on the exact meter reading dates would be necessary to be able to size a heat pump solution, and more information on the zone radiation sizing would be necessary to drill down with more precision on what makes sense on a boiler (or water heater) solution.

    The real load at -10F could easily be in the low 40Ks or the low 3oKs, but there is clearly no need for a 130KBTU/hr boiler for heating the place. The 3x-4x oversizing is buying nothing but excess standby loss- there probably isn't even enough baseboard in the whole house to emit the full output of the RV5.

    For a heat pump solution it's well worth running a room-by-room Manual-J or I=B=R type heat load calculation to be able to properly size the cassettes/heads/ducts with reasonable room to room temperature balance. If the temperature balance seems pretty good with the existing baseboards the relative amount of baseboard in each room could be used to infer the relative loads as a sanity check on the system design. The cooling & heating loads of the walk-out basement portion have very different characteristics than the fully above grade spaces, so it will have to be zoned at least by floor to have reasonably good comfort control.

    Typical tight fully above-grade 1200' of living space with low-E windows and 2x6/R20 over an unheated but insulated basement would come in at about 17,000 BTU/hr @-10F, so there may be some low hanging fruit on the air sealing and insulation front. If the boiler room isn't inside the insulated space that could be exaggerating the fuel-use load numbers, since most of the standby losses are then truly lost.
     
  9. lp20th

    lp20th New Member

    Joined:
    Sep 9, 2019
    Location:
    New England
    Thank you once again, you are going well above and beyond anything that I would expect to see from anyone responding to this post. I am learning a great deal from your analysis and am grateful.

    As I mentioned before I need to get to the house and measure up all linear feet of baseboards for each zone, hopefully some time next week.

    I actually do have the meter read dates and should have included them before:

    Some data points for propane usage:
    November 2018 - 101.68 gallons, 3700 cu. ft. $203.26 read date 11/27/18
    December 2018 - 109.92 gallons, 4000 cu. ft. $219.73 read date 12/27/18
    January 2019 - 134.65 gallons, 4900 cu.ft. $269.75 read date 1/28/2019
    February 2019 - 112.57 gallons, 4100 cu. ft. $225.23 read date 2/25/2019
    March 2019 - 95.43 gallons, 3400 cu. ft. $186.77 read date 3/25/2019
    April 2019 - 52.31 gallons, 1900 cu. ft. $104.37 read date 4/24/2019
    May 2019 - 24.73 gallons, 900 cu. ft $49.44 read date 5/28/2019
    June 2019 - 5.5 gallons, 200 cu. ft. $10.99 read date 6/18/2019
    July 2019 - 13.74 gallons, 500 cu. ft. $27.47 read date 7/26/2019
    August 2019 0 8.24 gallons, 300 16.47 read date 8/27/2019

    The house has vaulted ceilings over the main living area which is about 1200 sq ft. The roof is open truss design with blown in fiberglass insulation, about 16-18” deep. Other areas are conventional ceilings again with the blown in insulation. The basement ceiling is a suspended drop panel acoustical tile, there is no insulation in the ceiling joists between the floors.. The utility room is insulated but not sheet rocked. One thing I noticed and am going to remedy is that the band/rim joist in the basement has no insulation, it is hidden above the drop ceiling but I think something should be in place there. I am thinking about installing 2” rigid foam, to get about an R10 and help seal up any air leakage. The pipe runs for the upstairs radiators are very close to the rim joists and that is of some concern especially in an extended power outage in the winter.

    The southern exposure of the house has 3 large sliders, two 8’ and one 6’ on the main level and one 8’ at the basement level. They appear to be of good quality and tight for sliders but they are sliders, great on a bright sunny winter day. There are no skylights.
     
  10. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    Are you in US climate zone 6 (in blue) or zone 5 (green) on this map (you're pretty close to the boundary in any event.) Cheshire & Hillsborough county is still zone 5, Merrimack & Sullivan counties are zone 6:

    [​IMG]

    The air leakage at the foundation sill and band joist is usually more than all window & door crackage combined in most homes (!). In your climate insulating it with closed cell spray polyurethane from the subfloor above down to and over the top of the foundation will also air seal it quite well, and is usually a good investment in comfort & efficiency.

    IRC 2018 code minimum for basement walls (including band joists) in either zone 5 or 6 is R15 continuous insulation, or the performance equivalent thereof where thermally bridged by studs/joists, not R10. With expensive fuels such as LPG it's definitely worth taking it to at least that current code minimum.

    That would take ~3" of climate-damaging HFC blown closed cell foam (at about $3 per square foot at typical pricing) on the band joist, or ~2.5" if using more benign HFO blown foam (at about $3.50 per square foot).

    If that's a bit too rich for you, it's fine in your climate to use 2" of foam + "contractor roll" R13 batts nicely sculpted to fit with no gaps using a batt knife, saving a small amount if done DIY, but for most people it's not worth it when only looking at the band joists. If insulating the walls, 2" of cheap EPS foam (or 1.5" of rigid polyiso) + 2x4/R13 wall gets you there with low moisture risk on walls that will be fully finished conditioned space. If you're in zone 5 it's moisture-safe to back off to 1.5" of EPS or 1" of polyiso on the foam layer.

    Is the utility room insulated at both the foundation and the garage side? Are the exterior walls (and door) of the garage insulated and reasonably air tight? (Garage doors can be pretty leaky.)

    Taking the daily HDD55 data from 11/27 through 2/24 comes to 2581.1 HDD, taking it from 11/28 through 2/25 comes to 2586.1. Since the HDD for the day the meter was read isn't a full day, averaging them is the right thing to do, which comes to 2583.6 HDD55.

    That's 2.3% fewer than in the 2466 HDD used previous analysis, so it's a slightly higher BTU/degree-hour, so the implied loads are about 2.3% higher. Rather than 33,975 BTU/hr @ -10F it's really 1.023 x 33,975= 34,756 BTU/hr @ -10F, not that it's enough to affect the equipment choice. Equipment that can supply 35K @ -10F is going to cover it. Since the output of that boiler is 144K (at least for the gas version) it's more than 3x oversized for the load, and the as-used AFUE is going to be lower than the nameplate numbers. A heat pump solution capable of 30K @ -5F would probably still have you covered at -10F without any auxiliary heating backup. Most 2.5-ton cold climate mini-splits would cover it and all 3 tonners will. Using separate, right sized systems for each zone is usually more efficient (and often cheaper to install) than a single outdoor compressor unit serving multiple zones.

    Getting this totally right would require a more formal room-by-room heating & cooling load analysis of the "after upgrades" condition of the house, if more air sealing and insulation improvements are planned.

    There are some fairly cheap modulating-condensing LPG boilers that could work and would probably save more than 15% on the fuel use, but if you'll be installing a cold climate heat pump solution for the AC and using the heat as your primary heat there's no "payback" in swapping out the ridiculously oversized beastie boiler that works for a shiny-new mod-con. Keeping the boiler operable but using it sparely works just fine as the "Hail Mary" backup for when it hits -25F during a major Polar Vortex a disturbance cold snap and the capacity of the heat pumps are sliding off a cliff and they can't keep up.
     
  11. lp20th

    lp20th New Member

    Joined:
    Sep 9, 2019
    Location:
    New England
    I am in Zone 5, Antrim, in Hillsborough county, right on the Antrim/Hillsborough town line.

    I need to take a closer look at the rim joists and see the best most practical way to insulate them. I see that there are DIY foam kits but I could see this as being a mess and cumbersome to apply especially when dealing get with a drop ceiling and an already finished living space. The rigid foam board with additional Batts added may be the route to go. But It would be good to seal/insulate the sill plate as well.
     
  12. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    It's possible to do an OK job on the foundation sill & sill plate using cut'n'cobbled foam board. To make life easier insulating any ledge of foundation in front of the sill plate use 1.5" foam board (same thickness as the milled 2x lumber sill plate, caulking it in place with either a polyurethane caulk forulated for concrete (but not the "self leveling" stuff), can foam, or foam board construction adhesive. Insulate the band joist with the same stuff, and install R15 batts (rock wool preferred, but fiberglass is OK) on top of that, and against the foam in the band joist bays. When insulating the band joist between floor joists cut the rectangles 1/2" smaller than the available space, tack it to the band joist with a few blobs of foam board construction adhesive (or 1-2 cap-nails) to have enough space to insert the tip of a can-foam gun for sealing it in place.

    To take the pain & mess out of the foam cut'n'cobble, take a 4-5" steel wallboard taping knife or putty knife and sharpen the edges. With a 4' level or other straight edge as a guide it's dead-easy to make quick clean cuts in 2" or thinner foam, as demonstrated here. Foil faced polyiso is the easiest/cleanest, with the least amount of mess. Type- I EPS with facers on both sides would also be pretty clean, but there'll be some amount of bead-crumb if using unfaced EPS (though only a tiny fraction of the mess of cutting it with a saw.)

    For sculpting the batts to near-perfection, use a 10" bread knife or a purpose made batt knife, and cut the batts ~3/8" - 1/2" taller than the available space to guarantee a compression fit. Tuck in the edges & corners make sure there are no voids, then gently tug it out to the original 3.5" loft.
     
Similar Threads: Burnham Revolution
Forum Title Date
Boiler Forum Burnham Hydronic acting strange after Bleeding May 26, 2019
Boiler Forum Burnham ES2-4 Apr 11, 2019
Boiler Forum New controls for older Burnham boiler? Dec 10, 2018
Boiler Forum Recommended Burnham thermocouple? Oct 18, 2018
Boiler Forum Burnham Alpine 150 ModCon likely oversized and not working at highest efficiency Jan 8, 2018

Share This Page