"New" 111 year old house with boiler control issues..

Discussion in 'Boiler Forum' started by Pippen S., Apr 30, 2021.

  1. Pippen S.

    Pippen S. New Member

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    Hi All!

    I've gotten a crash course over the last 2 months of owning an old Victorian style home in Rhode Island, seems like everything is going wrong with this heating system.

    So a quick description of the heating system: there are a total of 6 zones coming off of a Slant Fin S-120 DP. 4 Zones hit different sections of the main house (2200 SF), 1 controls the guest cottage, and one controls the indirect hot water tank.

    So two weeks after we moved in the coil of the indirect tank went, and I just replaced that. There have been a few other minor issues like the HyVent? and a new control valve but otherwise it's just been acting funky and getting worse, and it just has to do with the honeywell controls I think. What happens at this point is as long as the heating system is firing and staying hot there is no problem, but now that it's getting warmer the boiler is staying cool for long periods of time, and when it cools off at night and the thermostats call for heat, it never kicks back on. The valves will be open but the boiler just sits cold. If I shut off the boiler for a few seconds and restart it it kicks right on and heats up just fine, though it seems to be getting worse? It's like it won't maintain itself at a hot temperature either once it reaches the 180 i've set it to. Any advice would be sorely appreciated, it's been a rough couple of months trying to figure out what I need to do with this system.. and we were trying to replace the roof this year, so that was going to be our big expense. ugh.

    Of course there's another thing that's stressing me out is the return plumbing into the boiler is shot, and I think is part of the reason why the hot water tank coil rusted out in just over 10 years. The connection is TERRIBLE, and I would love to know if there's any way I can replace the connection or if I'm going to replace the entire boiler when it goes? I've literally seen steam escape from the rusted out section as the boiler is reheating over the past few days..

    So this is a layman's account of an incredibly hard system for me (moving from a small house with steam) and I'm just trying to get my "sea legs" under me for what i'm in for trying to get this system up and running well.

    Thanks for all info, let me know if I can provide any more information and I'll follow through with that.

    Pip.
     

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  2. fitter30

    fitter30 Well-Known Member

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    Retired service tech
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    By cycling power it resets the honeywell burner control then tries to restart the burner. Need to get the numbers off control download the manual. Should be a flashing light that corresponds to a failure. Here is a manual to dow load just scroll down to downloads. 180* water is set for probably 0*. Does the hy vent have any numbers? What pressure is the boiler running?
    https://www.supplyhouse.com/Slant-F...on-Boiler-Intermittent-Pilot-Ignition-Nat-Gas
     
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  4. fitter30

    fitter30 Well-Known Member

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    Blue pex with hose clamp is the wrong fitting on the copper. Honeywell L8143 control hi limit. 180* water temp might need that temp at 0* not now 160*. Cycling power resets the the burner control and wipes out its memory. Before cycling power need to look at the flashing light on the.control count the flashes. Diagnostic may be on the control or might have to do a search for the manual. Hy vent any numbers on it and whats the problem. That rusty fitting next to that tee going into the boiler thats the return leaking? Leaks in any boiler steam or water brings in fresh water with that oxygen and can shorten the life of the boiler.
     
  5. Pippen S.

    Pippen S. New Member

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    Thanks for the replies man super appreciate it, there's no lights or anything on the control panel, I'm totally in the dark when it comes to understanding these controls. I'll download the control manual and take a look through it.

    The Aquastat is the Honeywell L8148 E 1273, like you said. i'm a little confused about what you're saying about switching the 180* to 0*, when i look at the temp controls it goes from 140* to 220*, what would putting it to 0* do, would that mean it would never heat up? Sorry just confused about the whole 0* thing you're talking about. the boiler cycles from 180* to 0* right now if no heat has been called for a while.

    I'll attach photos of the box. I don't see any flashing lights or anything telling me that something is wrong with the Aquastat, but that's gotta be the issue right?

    Hy Vent just had a slow leak from the top so I replaced it in kind, it says 240F. Attached a photo of that.

    The rusty fitting is the the return going back into the boiler, yes. I think that's part of why the coil in the indirect hot water tank corroded in ~ 10 years, and i'm wondering what I can do to replace the connector and why it's rusted out so bad? or should i just plan on replacing the boiler if that piece goes, which i'd hate to do
     

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  6. Pippen S.

    Pippen S. New Member

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    oh also what should I do with that blue Pex supply to the copper connection? Want to make sure everything is legit with this system while i'm at it.
     
  7. Dana

    Dana In the trades

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    01609
    I don't have any better insight as to what's confusing the controls than fitter20, but the boiler is pretty ridiculously oversized for the load, and firing at a very low duty cycle even during the middle of the heating season. T

    The Slant Fin S-120 DP has a DOE output of 101,000 BTU/hr which makes it ~3x or more oversized for an insulated (except for the basement/foundation walls) 2200' house in RI, assuming there is glass in the windows and the exterior doors can close. Even if it's an uninsulated leaky balloon framed house it's likely to be more than 2x oversized for the design load. (ASHRAE recommends 1.4x, AFUE testing presumes 1.7x.)

    If it's more than 20 years old it may be worth considering retiring it before it's dead (or not), depending on your goals for comfort, efficiency & boiler lifespan. Fixing minor control issues is cost effective, but at your likely oversize factor it's probably worth at the VERY least retrofitting a heat purging economizer control (DIY-able on the cheap for those with reasonable electrician skills), bypassing/replacing some of the aquastat controls. A heat purging economizer will retrieve most of the efficiency hit from being grossly oversized. At 3-4x oversizing that can easily hit a 10-15% or higher reduction in fuel use.

    If you've been in the place since December it's possible to use the boiler's namplate efficiency, local weather data, and the January/February gas bills to directly measure the 99% design load, if you're curious. That would give you a good idea as to the actual oversize factor and how much a heat purging boiler control might save.

    If considering outright replacing the boiler it would be important to know the amount & type of radiation, as well as the 99% design load to properly size the boiler, including higher efficiency modulating condensing boilers. If it happens to be mostly high volume Victorian era radiators the boilers often need to be grossly oversized to avoid excessive & destructive condensation on the boiler's cast iron heat exchanger plates from excessive return water that's too cool, whereas modulating condensing boilers are designed to not only tolerate but take advantage of condensing temperatures in the boiler to gain significantly higher efficiencies.

    But if the oversized boiler is still in good shape and you're keeping the money is usually better spent on air sealing and insulating the house (including the foundation walls & band joists) to achieve the same fuel savings as swapping in a mod-con. The improvements to the house last longer than a new boiler, and do more for improving comfort & indoor air quality than a mere boiler swap ever could.
     
  8. fitter30

    fitter30 Well-Known Member

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    Retired service tech
    Location:
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  9. Pippen S.

    Pippen S. New Member

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    Hey Guys,

    Thanks as a novice this gives me a lot to look over.

    So in terms of the boiler being oversized - i don't think we have much in the way of exterior insulation currently. The house is around 2200' but there is a large attic we plan on finishing that will add another 300-sf, and there is a 20x20' guest cottage on the property about 25' away from the house that is also heated from the boiler in the main house. My previous house was steam and was built in 1920, this is an old Victorian that has been converted from steam radiators at some point in the past (you can see obvious holes in the floors and water leak damage indicative of steam radiators) to baseboard heating throughout both houses.. I'll need to measure the general lengths of all of those if I do want to size a new boiler.

    That being said, Dana, I do think it's pretty oversized, it fires up super quick and gets to temp, then shuts off and on pretty quickly when it's calling for heat continuously. It's not happening now that the weather is turning but was in the colder months. I did attach a photo confirming the BTUs of the system(partially covered by a switch now)

    Also, we moved into the house in mid-February, which is the coldest month here, I'll definitely use your links to try and determine 99% load from the data I have, even though it's a little incomplete.

    I'd really rather not replace the boiler if I don't have to, it seems to be fine other than the return pipe that is rusting out pretty bad. Fitter30 - I'm sure that's where the leak is happening (see attached photo), I'm worried about disintegrating the connection if I wire brush the area, and if I'll then be able to replace the connection to the boiler or at that point need to replace the whole thing. I also think that connection is why the water in the system so quickly rusted the indirect hot water tank I just had to replace.

    in summary - i'd like to keep the boiler and replace the return piping that's totally rusted out, I'm definitely going to look into retrofitting a heat purging economizer control thanks for the tip, and I'm going to work on getting the house much better insulated than it already is. We have a program out in RI run by the state where they send an efficiency engineering contractor out to inspect the house and give you basically 50-75% off the work with a 2-5yr interest free loan, which we have an appointment for in the next couple of months.

    Thanks for your help ! you think that rusting return pipe is replaceable?! I'm gonna read through that controls manual and see if I can't figure out what the heck is wrong with the controls and why it doesn't always fire up when it's calling for heat right now.
     

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  10. Dana

    Dana In the trades

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    You absolutely DON'T want size hydronic boilers by the size of the radiation- that would only be appropriate for a STEAM boiler.

    The baseboard lengths become relevant with a modulating condensing boiler in order to know whether it not it will short-cycle when in operating at condensing temps. It's the MINIMUM modulated output of the boiler that matters more than the maximum.

    If you're finishing the attic to the current code air tightness & insulation requirement the it's likely that whole house load will go DOWN, even with the additional 300' of conditioned space.

    Heating a 400' guest cottage 25' away from the house with the same boiler incurs significant distribution losses,(unless the heating plumbing is buried more than 2' down and insulated to at least R8) but shouldn't add more than ~10,000 BTU/hr to the peak load, even with the distribution losses. It may be worth decommissioning that zone at some point and installing a 3/4 ton mini-split heat pump instead.

    Cycling on/off during a continuous call for heat is an indication that the boiler is oversized even for the radiation. If under those conditions the burn times are <5 minutes with 10 or more burns per hour it's taking a significant toll on efficiency, and shortening the life of the ignition controls.

    At an entering water temp (EWT) of 180F (average water temp of ~170F) it takes about 200' of typical baseboard to emit the full 101,000 BTU/hr DOE output of that beast without any cycling at all. If the system is broken up into several separately controlled zones (how many thermostats are there? Looks like 4 zone valves, plus a 5th for the indirect) it could be short cycling on zone calls, since no single zone has anywhere near 200' of baseboard. If the main house zone has at least 150' of baseboard all operated as a single zone it would cycle, but shouldn't short cycle. Measure up the baseboard zone by zone, see what you come up with.

    I'm guessing the (against all rational reason) upsized the boiler for the indirect water heater. A 50 gallon water heater with a ~30,000 BTU/hr output is sufficient for most homes, and unless you have large spa tubs to fill you don't need anywhere near 100K of boiler output to keep up with both the hot water load and the heating load(s). (Upsizing the tank is usually a better solution than upsizing the boiler for serving spa tubs.)


    I'm practically your neighbor, less than 50 crow-miles to the NNW of your ZIP code. This February/March was unusually warm & sunny, which is going to skew the load numbers a bit, but go ahead and run the numbers on your very first gas bill anyway (or post the move-in and first meter reading dates and gas amounts here and I'll run them for you), it won't be quite as accurate but close enough to estimate the oversize factor.

    [​IMG]

    That looks like the seal between the first cast iron plate in the boiler and nipple is leaking. It may be worth trying to fix, but it's likely to just breaking/stripping the threads on the casting when pulling the nipple out. Don't attempt the repair until the heating season is actually done, so you have time to deal with whatever happens and not forced into a panic decision. It's one thing to be without hot water for a few days/weeks, quite another to deal without heat, even during only mildly cold spring weather.

    Given that picture, as long as you can get the boiler to fire by resetting it with a power-cycle you might as well put off fixing the ignition problem until you're sure the casting in the boiler isn't going to crumble when fixing the leak.

    In the mean time, run the fuel use heat load numbers, and measure up the baseboard zone by zone. At condensing temps the same baseboard only puts out ~200 BTU/hr per running foot (instead of 500 BTU/hr per foot at an AWT of 170F).

    Taking a "Hail Mary" at where the load and zone-baseboard numbers are going to fall, there are several decent 80K-in mod-cons out there with 10:1 turn-down ratios capable of throttling back to ~7600 BTU/hr-out at low fire. When set up correctly they can run a zone with only (7600/200=) 38' of baseboard with NO cycling at all during continuous calls for heat, yet can ramp up to 70,000 BTU/hr or more at high temp when needed.

    One of the less expensive and decent-value boilers in that range is HTP's UFT-080, (<$2KUSD for the "-W " wall hung version), which comes pre-plumbed with a second port out the bottom of the boiler to support an indirect water heater. It has fewer bells & whistles to program than some others, but it's pretty decent, and easy to design around.

    Unlike water-tube boilers can usually be dropped in directly to baseboard systems like yours without any significant changes to the system plumbing. With a zone-valve based system like yours you'd want to replace the system pump with a "smart" ECM drive pump that responds to pressure feedback, and run a dedicated pump (like a Taco 007e, or re-use the existing pump) for the indirect but it's not a rocket science hydronics design problem to make that boiler work well on your system with minimal changes. Take a look at the system schematic in Figure 8 of the manual , and compare it to what's currently there. With your system it is even DIY-able for people with reasonable plumbing & electrical skills- a competent pro with one apprentice helper could/should easily be able to knock it out in an afternoon, maybe a full day if working alone.

    HTP's company HQ is less than an hour's drive from your ZIP code, so I would expect local product support for the UFT series boilers to be pretty good. (It's pretty good in my area.) The UFT-80W exactly the boiler I would install at my house if the tankless water heater I'm currently using as a boiler were to crap out this week.
     
    Last edited: May 5, 2021 at 3:10 PM
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  11. fitter30

    fitter30 Well-Known Member

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    Location:
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    If you don't know how old the boiler is serial number looks like it 485648
    Identify the serial number on the rating plate of the boiler and then call Tech. Service at (800) 873-4346
    With a standing pilot probably 35-40 years old.
     
    Last edited: May 5, 2021 at 5:41 PM
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  12. Pippen S.

    Pippen S. New Member

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    Thanks! I'll check it out the age of the boiler when I have some free time tomorrow today or tomorrow.
     
  13. Pippen S.

    Pippen S. New Member

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    do you include the lengths running to the baseboards from the boiler, or just baseboard length?

    That's good to know, at the rate projects are piling up on this old house it'll be a few years before it gets done though...
    The cottage is fed through a 4" conduit direct buried about 6' below grade, so not losing a lot of heat to distribution I don't think.

    That was definitely happening in the Winter. I'm so frustrated as the the previous two days the boiler would fire right up in the morning when called for heat and get to temp and stay there for the day, this morning it just didn't turn on, the inconsistency is driving me crazy.

    I should just measure baseboard lengths, correct? Don't (or do?) include the lengths running up and to the baseboard?

    There are 4 Zone valves in the main house, +1 Zone for the indirect, and +1 zone for the guest cottage.

    No large spa tubs or anything like that, just an oversized boiler! I will look at the age of the boiler as it may just be a remnant of the steam radiator system that was in here before?

    Howdy Neighbor! Let me buy you lunch or a beer or both if you're in the Providence region sometime, I definitely appreciate the plumbing info you're passing along. Guess I'll be resetting the boiler for another few months then, good to know. I'll post the numbers but it might also be skewed by the fact that the boiler was heating the water tank to 180F when the indirect's coil failed out a few weeks after we moved in (what timing!) I'll have to double check but i know our gas bill was fairly large after that happened and we spent a few weeks dealing with that.

    I'll definitely wait until July to try anything with that nipple repair.

    Just to reiterate, do I want to use just baseboard lengths, or do I need to estimate lengths of the piping from the boiler to the baseboards?

    Okay, a few things. Looks like a solid boiler and i'm definitely interested. Does it make sense to get the Wall mounted or can I just put the free standing version in the area of the existing and re-pipe in that way. I do think I could do most of this myself, but the controls aspect are what end up throwing me off. Have a plumber acquaintance from work I could probably hire for a day to get it in. I could just tie it directly into the existing blower as well? The 3" Vent Screens from the components list is throwing me off.

    Figure 8 shows pretty much exactly what I have, except for maybe the differential pressure bypass valve? and what is the 'makeup water', do I have that? is the low-water cutoff integrated into the boiler?

    I just bought an HTP SSC-50 as my indirect, good to know they're so close and responsive. Good to know the UFT-80W is what you would install! I'm tempted to buy it and have it on hand for when I try to repair the boiler and it invariably is un-fixable..
     
  14. Pippen S.

    Pippen S. New Member

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    Might as well attach this note here: our Gas Bills have been as follows so far:
    02/06 - 03/15: 55.566 Therms
    03/5 - 04/07: 149.205 Therms (big jump from the broken indirect coil we were dealing with for 3 wks)
    04/07 - Current: 94 Therms approximately

    I have my parents in town (in the guest house) through the weekend and a lot going on, but I plan on going through all of the information you've given me next week and really trying to get a good grip on how I should be focusing my efforts to resolving my boiler issues.

    Thanks to both of you!
     
  15. Dana

    Dana In the trades

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    Only the baseboards themselves are counted in the baseboard lengths. Any plumbing external to the baseboard housing does not count.

    A 4" conduit carrying both the supply & returns would need to be full of closed cell foam insulation to not have a measurable impact on distribution loss. I'm guessing it's not insulated, which makes it about the same loss as an additional 50-100' of uninsulated plumbing in an unheated basement that has insulation in the basement ceiling (guaranteeing that the heat lost from the distribution pipe doesn't support the heating of the floor above.) It's still pretty small in the grand scheme of things- a low single-digits percentage of the total heating bill in the house at it's current state of air sealing & insulation.

    The UFT-80F floor mounted version is usually a couple hundred USD more than the UFT-80W wall-mount, so if it makes the installation any easier it's not a big deal to go with one vs. the other. Internally they are functionally identical using all the same parts, just arranged slightly differently.

    The "makeup water" is basically an auto-fill/pressure reducing valve, which you probably have. They are not essential. You DO want to include a differential pressure bypass valve, which reduces the "water hammer" effect of when the zone valves close. It's just easier on all the system components to have that bypass valve open up, limiting the peak pressure.

    You don't necessarily have to buy the boiler ahead of time- just be sure to call and check that the local distributor (or HTP on in Fall River) has it in stock the day before you dive into repair attempt. The floor mounted version is more likely to be out of stock than the more popular wall mount. If you're not finding the floor mount in stock, note that the exact same boilers are sold under the Westinghouse brand label as the WBRUNG-080W (or 080F) The tech help line for Westinghouse rings at HTP headquarters- they are truly identical from a hardware point of view, but the marketing & distribution & warranty support channels are different.
     
  16. Pippen S.

    Pippen S. New Member

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    Boiler was put in in 2006.. Thought it would be older!
     
  17. Pippen S.

    Pippen S. New Member

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    Thanks, that's smart. I'll give you guys an update when I take an attempt at it once the weather heats up a bit.
     
  18. Dana

    Dana In the trades

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    It's rare but not unheard of for a cast iron boiler's casting to fail in only 15 years, so if you're lucky the nipple will come out easily and the replacement can be sealed. You might pull the burners out for a cleaning and with a bright light & mirror take a peek up into the fire-side of the boiler plates (or reach in and snap a pic with a phone camera) to see how rusty crusty they are. If they are very rusty it's likely to have been chronically operated with entering/return water in the condensing zone (<<130F) for a good part of it's life, which may be over.

    If it's caked in soot the pressure on the gas valve needs to be adjusted (by a qualified burner tech), and the soot cleaned out.

    Something like this would be pretty good:

    [​IMG]

    If it's all clogged with flaking rust it has been operated too cold. If clogged with soot it can be cleaned, and the fuel/air mixture adjusted by a tech.
     
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