Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Cold Start??

Bob Bona_4
Bob Bona_4 Member Posts: 2,083
Ron. Cold start for heat only boilers can be tricky. If the ambient around the boiler is not arid, then there can be problems..


  • JC_7
    JC_7 Member Posts: 4
    Cold Start??

    I just had a 45 gallon indirect installed, what a difference from the tankless coil that I was previously running. Anyway, should I run my heating system cold start? I have a Honeywell L8124A aquastat, so I would have to get a new one that does not have the low limit dial. Also, I have a Tjernlund power vent, no chimney (unfortunately). Should I just leave well enough alone and turn the low limit down to the lowest setting on the L8124A, or should I get a new aquastat?
  • realolman
    realolman Member Posts: 513
    I'm sorry I

    don't have an answer to your question, but as someone who has a tankless in his oil burner, and quit using it because I think it is uneconomical, I would like to know why you like your indirect so much.

    Maybe I'd be interested in getting one.

  • I don`t think

    cold start would hurt your boiler, and perhaps the LL function could be disconnected within the L8124A and still use the HL, not sure. The TJ proves the draft conditions, then tells the burner to start, so nothing there to concern yourself about. Really another "simple" aquastat and a Taco 502 relay are not big-ticket items though. You can even get "priority" if you wish.


  • my opinion would be get rid of the 8124,and put in an 8148 cold start aquastat,you don't need to have the boiler maintain constant temp now
  • David Sutton_6
    David Sutton_6 Member Posts: 1,079

    What kind of boiler is it? if the boiler is large you will reverse the process till the boiler catches up, when the tank sits at temp and the boiler cools down, the tank calls to be reheated the burnner starts and the circulator starts , the 8148 will cool down the inderect before it starts to reheat it, set the low limet to 120, you'll limit this, and help keep the boiler dry during the summer,If you go with the 8148 go with a 6006 to stop the circ from running till the boiler heats up.

  • brucewo1b
    brucewo1b Member Posts: 638
    Just be aware

    That many boilers that have spent years at 160 degrees and above will leak when put in cold start mode I would slowly turn it down over time and see what the results are.
  • JC_8
    JC_8 Member Posts: 2

    Showers were mostly OK, but filling a tub was essentially impossible for me with the tankless coil. The indirect provides a more even temp, while with the tankless, temp would vary (always adjusting the faucet while showering, doing dishes, etc.). Also, my boiler runs less often.
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    Another way around that

    is to pipe it primary-secondary, run the indirect as the priority zone, and put an aquastat (strap-on will do) on the primary loop to keep the indirect secondary circ off until the primary loop reaches 130 or so.

    When the indirect calls, the other zone secondary circs will stop, the boiler will heat up (with primary circ running) until it reaches the setting of the primary-loop aquastat, then the indirect circ will start.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • I have the same setup

    I was using the coil for hot water and added an indirect . Very steady hot water temp and a virtually unlimited supply now . I use the coil for the bathroom radiant ceiling now ( closed loop ) - works great .

    I would keep the 8124 , set the low limit as low as it will go and set the differential as high as it will go . 3 reasons for that -

    Depending on how old the boiler is , if it actually gets to room temperature things might start to leak .

    More than likely the boiler will rarely get to room temperature with a call on the indirect during the day and at night sometimes .

    And if it does get to room temp often , cleaning a cold start boiler can get hairy compared to one that maintains a minimum temp .
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592
    Disable Low Limit Function

    My $.02 I am quite surprised by all the response posted to keep the low limit function. Why would you want to fire the boiler if there was no hot water demand and piss heat energy up the chimney for no purpose. If all these other comments had substantial merit to them, the boiler manufacturers would be shipping packaged boilers with the L-8124A on them, or at worst case offer it as an option.

    Well guess what.......... they don't ship that control on a boiler without a tankless, and they don't offer it as an option. To keep it and maintain boiler a low temp all year, 24/7 in this scenario is ridiculous and wastefull in my view.

    If your like most people, you use hot water 1-2 hours a day. Your indirect I'm sure is very well insulated and probably has a standby loss of approx 1/2 - 1 degree per hour. If no one were home for the day, the indirect may turn the boiler on 2-3 times during a 24 hr period. During these cycles, it heating water to replace the standby loss of the tank -which is minimal due to the amount and R-Value of the insulation used to make it. Bottom line,you don't want to burn fuel unless you need to. Thats why the instantaneous wall hung hot heater market is growing so quickly.

    Your boiler is not well insulated and has a bunch of pipes sticking out it to conduct the heat away - it loses heat to the room its in. It's probably in your basement and you probably have no heat down there. But the basement is never really cold is it. I wonder why that might be??

    If you recall when you had your coil, the boiler probably fired 2-3 times an hour even if you weren't using hot water. Why? Because the boiler is not well insulated, and neither were the pipes connected to it. Plenty of extraneous heat transfer to your basement. Every time the boiler fired to maintain the low temperature, your were sending approximately $ .15 -.18 up the chimney for every dollar of fuel you burned - never getting any benefit from it.

    Disable the function on the existing control, or replace it with an L-8148A. Better yet, get a tekmar 256 indoor out door reset and then you'll really see how much money you can save.

  • Leo
    Leo Member Posts: 770
    Some brands

    Some brands can handle cold start while others make up in long service calls what was saved in oil. Post the make and model boiler you have so we can give you an honest opinion.

  • Agree w/ Ron Jr.

    Very little extra oil burned & older boilers that have been kept hot do weird things (read expensive) when that warm security blanket is completely removed.

    Ron (I believe that's 3 for this thread)

  • Ken_40
    Ken_40 Member Posts: 1,320

    Leaks that have been there for years, but so small that the water evaporates faster than it can puddle or drool, will suddenly be visible - because now, they will not evaporate and will be able to form, puddle and drool.

    This is not likely, but most certaoinly possible. One could "know" this beforehand if it were noted that system pressure slowly dropped over a year or two - without any other possible cause. If the pressure has stayed the same for years (and the PRV has not been feeding water on occassion) the system and boiler are tight, and - not to worry.
  • JC_7
    JC_7 Member Posts: 4

    Thanks for all the feedback. Pros and Cons to both, I guess. My boiler is a Utica, a little over 4 years old.
  • Ken_40
    Ken_40 Member Posts: 1,320
    Four year old Utica?

    > Thanks for all the feedback. Pros and Cons to

    > both, I guess. My boiler is a Utica, a little

    > over 4 years old.

  • Ken_40
    Ken_40 Member Posts: 1,320
    Four year old Utica?

    No problem!

    It's probably twice the size of the actual heat load, so cold start is not an issue either. (The load being smaller than the boiler output will make the boiler warm far quicker than the connected emitters can deliver, assuring over 140F operation almost any and every time. Turn it off during summer and enjoy the cool basement.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537

    don't you take this question to www.oiltechtalk.com? No one who services oil boilers on a daily basis would think cold starting a pin type boiler is a good idea

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    I concur w/ Mr. Secor

    The boiler will run enough with a properly piped and sized indirect to stay dry.

    Cold start it.
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592
    True but still disagree

    Hey Dave

    The reason the customer has the indirect is to store hot water to have on demand and not rely soley on the btu recovery capacity provided by the boiler. Following your example - if it is that close, that the ambient temp water fed by the boiler is going to have a negative impact on hot water consumption/usesage of the homeowner, I would say the indirect is undersized for the job.

    Increase the tank size by 10 gallons or so. The extra jacket losses would be insignificant. To maintain the 120 boiler temp for 24hrs when the actual draw occurs for average of an hour or so a day is costing the customer money besides the fuel.

    Having the boiler cycle 1-2 times an hour to maintain temperature just shortens the useful life span of the burner and the other electo-mechanical devices on the system such as pumps, relays,etc. I suppose if you were in the service end of things, this would be good for the service company but its bad for the consumer. You will increase his fuel bill unneccessarily and shorten the useful life of the heating equiptment.

    Disable the low limit funtion of the L8124A, or install a L8148A. Spend an additional approx $220 for and indoor/outdoor reset. This guys fuel bill savings would probably be 25% or more based on what he had before.

  • Glenn

    Cold starting a boiler has a time and a place . Buderus , MPO , Ultra , Viessmann and a few more triple pass cast iron boilers work amazing as cold start . System 2000 too .

    But there are serious drawbacks to making a pin style boiler cold start . Gaskets will leak , and cleaning the fireside of the boiler can become a disaster . Like Techheat said , check out Oiltechtalk and search for cold start threads . The majority of the fine technicians who work on oil equipment every day and post there concur .

    I have serious doubts the boiler fired 2 to 3 times an hour with no call for heat or hot water . Unles , maybe , it was a tin can or a Repco ( which is a tin can ) .

    I know my boiler fired maybe 2 times during the day when it was maintaining 180 for the coil - and ran for 2 or 3 minutes at a clip . My math is very rusty so bear with me . Figure 4 times a day just to maintain temp ( call it a cold boiler room or standby losses up the chimney ) - 15 mintues a day ? Burning at .75 or thereabouts I figure maybe 1/5 a gallon a day to maintain 180 . And you can only count that for the warm months , right ? Because in the cold months even a cold start boiler will be hot most of the day and night ? Figure 6 months , works out to an extra 36 gallons .

    But wait , we weren't talking about maintaining 180 . We were talking about maintaining the minimum setting on a triple aquastat - 120 or so ? BIG Difference in the gallon used . My fuzzy math says keeping some heat in the boiler all the time isn't as ridiculous and wasteful as you might think . Just my humble opinion .

    I do agree with you that a cold start control would be OK on a boiler with an indirect . My guess is the boiler will always have some heat in it or pumped in it from the indirect .
  • ralman
    ralman Member Posts: 231
    This is my experience.

    I have a peerless oil fired boiler with a tankless coil. It has a 105,000 BTU IBR rating. The aquastat is 140 low, 170 high with a 20 degree differential. The output of the coil is piped into an electric hot water heater. There are 3 adults showering, laundry, not much cooking. We never use the automatic dishwasher. From 7/29/2004 to 10/20/2004(83 days) I used 127 gallons of heating oil for the domestic coil only. That figures to about 1.53 gallons a day to heat hot water. I don't really know the daily cost to operate an electric hot water heater. I shut my boiler down in the summer now because the heat in the basement is unbearable. My electric bill is about 50 dollars more during the summer months with the boiler shut down, using the electric hot water tank only. I do use two 12,000 BTU window air conditioners which is responsible for some of the electric bill increase. EDIT: The oil burner is a Beckett model AFG. My nozzle size is .85 80 A Delavan and my pump pressure is set at 140 PSI which makes the firing rate one gallon per hour. The system is about 5 years old now.
  • Ken_40
    Ken_40 Member Posts: 1,320
    In my experience,

    boilers that had tankless coils, and later stopped using that aspect (using a separate gas H/W/H instead) all had the minimal water temp operating limit diasabled (otherwise, why would you want to get a gas 40-gallon water heater; other than to reduce scalding or tub fill shortfalls).

    I suspect I have done, or seen that done, many hundreds of times. To no detrimant of the boiler. Remember, I serviced everythjing I sold, and had 600 customers that we serviced at any given time, so my experience was not limited to new stuff only.

    I could count on one hand the number of leakers that were exposed by this chamge. I'm also positive the leaks were there for years, they were merely masked by heated evaporation!

    By far, the nrom is to have a boiler sized for D/H/W use, not heating laod. Because of this, virually all homes had two to four times the output required to heat the home; resulting in boiler water temps always shooting into the 140+ range on every cycle, simply because of the boiler being three times the load.

    Then too, adding more evidence of there being no condensing boogey-man, think of all the gas boilers installed in gravity systems, left as gravity! I did at least ten. One 20 years ago! The boiler got over 160 maybe 50 times in 20 years. No rust, no leaks. Even pumped gravities, most without any bypass, still run well - and in the 120-150F "problem" range.

    It is a potential problem, but IMO very over-blown as to certainty and actual impact.

    Think about this as well: When the R/A aquastat works, all heat goes into the shower water making. That water temp will almost always be in the 115-135F and the boiler on, constantly. During the entire shower, which in summer will be the only demand made, the boiler is almost always running in the sub-140F water temp range! The only exception being, when you get out of the shower and the low limit is satisfied - which might take what, a minute?
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592
    Cold Start fave less cycles to cause expansion

    All your points are valid. I would question that your boiler w/tankless only fires up 4 x during the course of 24hrs with DHW demand. Even if did, it is still radiating usually unwanted heat energy to the area it is in -wasting heat energy. It is not insulated the same as today's indirects are.

    If it only turned on a few times a day, you probably had a very wide differential setting, which would mean when it did fire, it would tend to fire longer. If it fired as infrequently as you say, it must be a big ol' boiler that had a very high thermal mass- 400lbs +, 8-12 gallons of water content, and a nice big nozzel?? Lot of unusued heat energy stored there.

    But here is the real test, if you had a sampling of 100 installations that were cold start, what percentage of them would leak after 5 years? What about 10 years? The point I'm making is, while leaks can and do happen, it is an insignificant percentage of the total installations out there. If this was a real frequent problem, we would see alot more warranty claims on leaking boilers. Now as a service man, you would see a higher perecentage of these leakers because thats what you do - take care of problems.

    Think about this -how much expansion/contraction is happening when you put the boiler through a firing cycle?
    When that flame comes on, what kind of temperature difference are you talking about in te boiler at the gaskets or push nipples? I don't know what it actually is, but clearly its hundreds degrees higher than the water inside. That where the real expansion/contraction takes place, and it happens whether or not you have a tankless coil.

    Infact, I would contend that the number of on/off cycles of an oil boiler with a tankless is 10 - 15 times or more than that of the boiler using an indirect. It is logical to assume this increased cycling would be what creates the potential for the leaks - not the cold start. If you maintain a minimal temperature, your cycling your boiler. Cycles = wear and tear.

    It's all in the numbers. Think about the installations you did over the past 10 years. How many times did you get a call to pull one out because it leaked? And if you did, what percentage of the total installs was it? I rest my case.
  • mikea23
    mikea23 Member Posts: 224
    Cold start

    Most boilers are intended to be cold start. If in fact leaks happen how much sooner are we talking about.

    If cold start systems reduce life expectancy by a few years who cares your fuel savings will pay for that and then some.

    No boiler should be in a home for 30+ years. In fact all of us including myself do a diservice to the customer by keeping old units runing. And to still be installing boilers with a coil is more of a diservice.

    Fuel costs are way to high in todays world. If we need to sacrifise longevity or even dependiblity in some cases so be it.

    Things like outdoor reset and cold start should be standard on all systems today. Some guys say people cant aford it but the fact is that the people that dont have alot of mony cant afford not to do it.

    Mike A
  • The 4 times a day

    was added to the times it fired up for hot water ( which I didn't count ) . More than likely with no call fo heat we ran about an hour a day total for hot water demand and to maintain 180 . I gotta work around the house today , so I'll do a little experiment . I'll let the boiler coast to 180 and shut er down and see how long it takes to drop in temp .

    I think there is no wrong answer here . Cold start can and does work . But I would never try to convert a 5 or 10 + year old boiler that maintained a high temperature all that time . A boiler that has a years old coil gasket , sectional O rings , circ gaskets , whatever leaks when a boiler goes cold . Believe me , I get my hands dirty working on ALOT old equipment - adding baseboard , cutting in an indirect , changing bleeders on convectors , changing a burner . Ulike Ken Secor's field experience , a very good percentage of the equipment we cut into does leak at the gaskets till the boiler heats up . I have to say though we do have a far greater percentage of boilers with coils in them than Kenny did .

    Don't pat yourself on the back so fast and rest your case . The past 10 years I've installed between 750 and 1000 boilers , ALL of them maintaining temperature . I've pulled out maybe a handful from section leaks .

    I won't rest my case , but it does favor my humble opinion , no ?
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592

    Mike Very well put.

    Being on the wholesale side, we sell 6 different brands of boilers. Get alot of exposure over the years to warranty claims. The typical cast iron boiler has 20year or longer warranty. If they leaked, people would be making leaker claims. Don't see very many leakers compared to the number of units we sell.
  • How many are

    cold start ? How many fire periodically for an indirect every day so there's always some temp in the boiler anyway ? Does every pin type oil boiler you sell go out with a cold start aquastat ? If not , what's the percentage ? We work on Long Island , and you would be very hard pressed to find any boiler cold start . This is the land of the COIL :)

  • Ken_40
    Ken_40 Member Posts: 1,320
    Since boilers with working coils

    are your experience, the question becomes, "What about the millions of boilers WITHOUT coils that the rest of earth sees more of"? And, they cold start, gas, oil, pins, no pins, slots, tubes, etc.

    Hell, even C/B 400HP water boilers in steel do cold starts.

    It is NOT an issue most of the time. Underline MOST.

    Look at steam boilers? Always cold start!
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592
    Maintaining Temp

    I understand and agree, there is a higher probablitly that a boiler installed for 10+ years maintaining temp would have a higher probability of leaking if changed over to cold start. The question is, whats is that probability? Is it significant? 1 in 10 (10% of the time), 1 in 20 (5% of the time, 1 in 50 (2% of the time)?? And if it did leak (from sections of course), does converting from a tankless to no tankless void the boiler warranty ? A good question but I don't think it does. If it did, make a warranty claim and get the customer a newer more efficient boiler. The customer is already spending dollars to install the indirect. The homeowner should be asking, and I would consider offering the marginal cost to change boiler too. Of course some can't afford to, but if they were shown that they would experience 10-15% savings in fuel consumption , that might be a big incentive.

    Ifthe boiler is over 10 years old, what is the forward useful life? I would think that would be a factor also. I still maintain excessive cycles shorten the useful life of any appliance.
  • Quick reply and the results

    I turned the boiler off for 3 hours . Peerless WBV3 ( 10 years old ) , BF3 , 30 Gal. Weil Plus .

    12 degree temperature drop . I'm not sure if the drop in outdoor temperature , or me going in and out of the house like a lunatic had any influence .

    Gotta run , I'll respond a little better later , take care Glenn .
  • Good point

    but I thought this discussion was centered around one type of system - pin style oil boilers with a coil .

    A 4 year old Utica boiler with a coil , to be exact . Which I believe is pin style ?

    Putting aside the gasket and O - ring issue , did you find cleaning cold start pin style boilers any different that boilers that maintained some temperature ? I'm sure you got your hands dirty on many a 68 series ? Any of them cold start ?

  • brucewo1b
    brucewo1b Member Posts: 638
    I agree with Ron Jr here

    in the land of tankless coils when a boiler goes down with a no heat call the most common complaint is water on the floor, and that is 90 percent of the time, buT also live where the Weil Mclean P-68 series was king at one time with the elastomer seals, also a common complaint with Utica SF series. Now I have also seen cold start P-68 with out boiler protection that had lost pins to rust over the year but still didn't leak at the seals because it was cold start from day one. Therefore my warning above and would it not be cheaper to keep turning down the LL before buying a cold start control to find out the boiler leaks when cold. I bet a warm start at 120 degrees will not be as ineffecent as claimed here many degress saved between 160 or 170 and 120LL.
  • mikea23
    mikea23 Member Posts: 224

    If it leaks it sounds like its time for replacement. Expanding the CI is not a fix. If your roof only leaked when it was closed you would still replace it. No heating system should leak hot or cold.

    Mike A
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537

    real problem is condensing not leaking coil gaskets.The boiler spends too much time below the condensing point in most cases even with an Indirect. I would not cold start a pin type oil boiler.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592
    temp drop

    > I turned the boiler off for 3 hours . Peerless

    > WBV3 ( 10 years old ) , BF3 , 30 Gal. Weil Plus .

    > 12 degree temperature drop . I'm not sure if the

    > drop in outdoor temperature , or me going in and

    > out of the house like a lunatic had any influence

    > .


    > Gotta run , I'll respond a little better

    > later , take care Glenn .

  • Ken_40
    Ken_40 Member Posts: 1,320
    I don't think so.

    You were the one whp brought upa concern over "pin style" boilers. The question was about cold start period. And yes, I've cleaned a ton of 68's. about half with coils and half without; the latter, being all cold starts. I found once we cleaned them annually, the soot and/or scale buildup was minimal. We took a full 10-15 minutes just to clean the pin "beds" completelky, even using the great trick of water dousing the pins after wire brushing. We had both the oversized bristles and the stiff shorty. Damaging the fire box by being forceful was a learning experience! We ran them all at a trace to zero smoke, finding the sulphur at less than zero worse than a dusting of soft soot at zero to a trace. Setup was time consuming, but worth it IMO. Not including travel and setup time, we would take 1.00 to 1.5 hours per cleaning of 98's, and we knew the filter size, .85X80H nozzle by heart. When no coil was present, we'd downfire 'em all to .65's We'd order them with the F-3 end cone, not the suggested F-5 (I think), just so we could downfire them. Hell, they were twice the size needed at full in/output anyhow!

    I believe we still service close to 50 of 'em. If cleaned and maintained, those suckers will still be runing when I'm dead. Beckett AF's on all of them - if memory serves.
  • Ken_40
    Ken_40 Member Posts: 1,320

    However, many ALREADY leak - but it evaporates faster than it can puddle -making it APPEAR the cooler boiler caused the leak; which is completely incorrect. It always leaked, you just couldn't see it!
  • The 68 series

    was a fine boiler . We used them to replace GE hangers in the kitchen .

    I did assume it was an oil fired pin boiler at first . The homeowner wanted advice tailored to his situation and I gave my very educated opinion on that assumption . My bad .

    But the thread did not start off about " cold start , period " , it's about cold starting a heating system that has an indirect and 8124 , but previously had a coil . " Cold start , period , is a little more broad subject than this homeowner was interested in , don't you think ?

    Ken , did you ever upgrade those 68s with a Riello ? If you did , how were the results ?
  • But one part of the question becomes

    does the boiler ever cool down enough to warrant the change out of the triple aquastat ? If it just sits there overnight and drops 40 , 50 degrees till a call for hot water , wouldn't the triple aquastat , set as low as it'll go , do the same job ?
  • Ken_40
    Ken_40 Member Posts: 1,320
    Well, when I respond under a post by anyone,

    It's usually in reponse to that person, not the first post in the thread. Had I been directly responding to the initial post, I would not have answered under your post, or anyone elses for that matter.

    That is how it's supposed to work right?

    And no. I never "upgraded" the AF to a Riello. In my mind, that's a down grade, not an upgade anyhow. I had so few problems with the AF, and got such good efficiency, under what basis would I even think of changing it?
This discussion has been closed.