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boiler suggestions, buffer tanks

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Comments

  • jrkeat
    jrkeat Member Posts: 71
    edited April 2020
    Does the shape of the tank make much difference, or will those short fat water heaters do fine in terms of stratification?
  • hot_rod
    hot_rod Member Posts: 22,024
    Tall tanks do tend to stack better. In the affordable, common residential size tanks there are not a lot of choices for tank dimensions
    Around 30 gallon to 50 you can find stubby or standard height options

    Stubbies are nice for under wall mounted boilers if space is at a premium
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jrkeat
    jrkeat Member Posts: 71
    What kind of plywood do you use for mounting? It seems like I should use a structural rated plywood, but most structural plywood looks ugly, and I'm trying to get my boiler room to a more finished look.
  • clammy
    clammy Member Posts: 3,103
    When I do plywood panels for mounting I tend to use at at min 3/4 interior and usually will paint before I mount . I’ll sometimes ask the ho what color or I’ll what there nationality is Brazilian ,Italian ,Germany or American and give them that cola4 scheme it’s really up to you . I always use a hi quality exterior paint stands up better and good hardware for mounting Spatz 2 inch screws work great and 1 1/2 for mount plates ,verse bar and piping brackets. As I always use the right screw and don’t use sheet rock screws the name should indicate what they should be used for . In a quick read if you need a buffer go w a 4 port tall and narrow either a 30 for smaller boiler and system and 50 for large I de be looking at your lowest boiler mod and smallest load to assist in sizing . Listen to hot rod the guy is a vast wealth of very helpful and truthful knowledge one of the top in this field and a hell & a nice guy . He speaks the truth peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • jrkeat
    jrkeat Member Posts: 71
    Exterior paint is a great suggestion.

    For the plywood, would you use something like this:
    https://www.lowes.com/pd/Plytanium-23-32-CAT-PS1-09-Square-Structural-Plywood-Pine-Application-as-4-x-8/3010111

    I'm happy to spend more or go to a proper lumber yard.

    It's incredible the number of things I've had to learn about.
  • hot_rod
    hot_rod Member Posts: 22,024
    When you go to a box store, shop their damages sheet goods. I've found some nice 3/4 finished surface, oak, birch, etc panels with small damage for less than new AC or CDX. Menards always has a rack full of damaged sheets.

    I don't like any of the coated particle board, they don't like being wet :)

    MDO if you can find it is the very best, it's what they make highway sign with, extremely hard surface, very durable. Sign supply shops are where you can find it, they often have partial sheets also.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jrkeat
    jrkeat Member Posts: 71
    I just did a gas pressure test BEFORE doing anything.

    The result: If I pressurize to 4 PSI, it loses .1 PSI per hour over 10 hours.

    This would pass under the official rules: pressurize to 3 PSI (using a meter with a full scale of no more than 15 PSI) and wait for 10 minutes. Over that time, you would have a .02 PSI loss, and you wouldn't see it on the meter.

    I've tested the meter for leaks (close the adjacent valve and see if it can hold 10 PSI for an hour), and I've coated each valve with bubble solution, and haven't found anything.

    Can I rate this as a pass? Is there anything else I can do without breaking into walls?

  • hot_rod
    hot_rod Member Posts: 22,024
    jrkeat said:

    I just did a gas pressure test BEFORE doing anything.

    The result: If I pressurize to 4 PSI, it loses .1 PSI per hour over 10 hours.

    This would pass under the official rules: pressurize to 3 PSI (using a meter with a full scale of no more than 15 PSI) and wait for 10 minutes. Over that time, you would have a .02 PSI loss, and you wouldn't see it on the meter.

    I've tested the meter for leaks (close the adjacent valve and see if it can hold 10 PSI for an hour), and I've coated each valve with bubble solution, and haven't found anything.

    Can I rate this as a pass? Is there anything else I can do without breaking into walls?

    Sounds like it is leak free. Know that pressure will change a small amount with temperature. Compressor air usually goes in warm, cools to ambient temperature. That could account for a small drop.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jrkeat
    jrkeat Member Posts: 71
    The pressure dropped from 4 PSI to 3 PSI over 10 hours. Isn't that larger than temperature can account for?
  • hot_rod
    hot_rod Member Posts: 22,024
    jrkeat said:

    The pressure dropped from 4 PSI to 3 PSI over 10 hours. Isn't that larger than temperature can account for?

    Its would depend on how much temperature change, and the volume of air in the system.

    Does it keep dropping or stop and stay at 3 psi?

    Test gauges and connections are prone to leak also, be sure to soap that.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jrkeat
    jrkeat Member Posts: 71
    edited April 2020
    hot_rod said:

    Does it keep dropping or stop and stay at 3 psi?

    Test gauges and connections are prone to leak also, be sure to soap that.

    It goes down pretty close 0.1 PSI each hour--I stopped after it got to 2.5 PSI. The tester is attached where the boiler used to go, after its valve. If you close the valve to the tester, that little space between the valve an the tester maintains it's pressure. Then, if you open it after, say, 2 hours, it will drop by 0.2 PSI. So it's clearly not leaking through the tester.
  • hot_rod
    hot_rod Member Posts: 22,024
    Well, if it drops to 0 you have a leak. Can you take it to 15 psi, easier to find a leak. Is it black steel pipe?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jrkeat
    jrkeat Member Posts: 71
    edited April 2020
    hot_rod said:

    Well, if it drops to 0 you have a leak. Can you take it to 15 psi, easier to find a leak. Is it black steel pipe?

    I do think I have a leak BUT it is so small that the system would still pass the code leak test. It will take many days to get to 0.4. PSI the lower limit of the meter. It will probably take 8 hours to go from 0.5 to 0.4.

    Yes, I can take it to 15 PSI. Yes, it's black steel. I'm not optimistic it isn't somewhere in the walls, though. I've checked the exterior of the 5 valves that are visible in the system.
  • jrkeat
    jrkeat Member Posts: 71
    edited April 2020
    I found a leak! The pipe coming out of the wall to my stove leaks just a little. Thanks for the 15 PSI recommendation!
    rick in Alaska
  • jrkeat
    jrkeat Member Posts: 71
    edited April 2020
    I'm wondering about my air intake vent.

    I've pulled out all the old stuff (all 530 lb of the cast iron boiler) and temporarily installed the little electric water heater, allowing me to work on venting. I installed 3" Centrotherm Innoflue SW in the chimney for the exhaust.

    I was planing to use the old air intake for the new boiler. It's a 4" flexible vent which runs horizontally about 25', shown in this picture:



    I notice, however, it's not on the list of approved materials in the Laars manual (though maybe they're just talking about the exhaust vent), and I've never seen it used with a condensing boiler. The Lochinvar Knight lists "Dryer Vent" as an acceptable material.

    Is there a good reason to not use the existing vent?

    I could put in a second 3" Innoflue SW line up the chimney for the intake.
  • SuperTech
    SuperTech Member Posts: 2,139
    That flexible vent pretty much is dryer vent. It should be ok to use, I'd rather see it done in sheet metal pipe, looks more professional.
  • jrkeat
    jrkeat Member Posts: 71
    I'm having a exhaust temperature measurement problem, and I'm wondering if anybody has any ideas.

    Things are set up enough that the DHW is working.

    The exhaust temperature reading is weird. When I turn the machine on, it produces a random number, sometimes in the >200 range, giving an error that shuts the machine down.

    The exhaust temperature never updates except when I unplug it and plug it back in. So if the boiler fires, the reading stays the same. But then if you unplug it (which shuts down the boiler) and plug it back in, you can get a new temperature reading.

    The temperatures it gives are SORT OF 10k Type 2 sensor temperatures, but not exactly. For example, when the sensor is 4.77k , the boiler gives 101F (should be 109 for a Type 2) and 4.00k = 109F (should be 117).

    Laars support is telling me that I should replace the sensor. I think Laars support is fabulous, but I think they're probably wrong.

    But I have no idea what the right answer is.

    Does anyone have any ideas?
  • jrkeat
    jrkeat Member Posts: 71
    It was a main board problem. Laars overnighted a new one, and it's fixed.
  • jrkeat
    jrkeat Member Posts: 71
    edited June 2020
    Old boiler (some zones are above the picture):

    New boiler and room finishing:






    I'm mostly done and about to leave town, so I thought I'd post an update. Please note any code violations you see.

    I reused the circulators, the control valves, and the control electronics.

    All the zones and the indirect tank work. I executed basically the last plan I proposed. It was a huge amount of work! The primary and the buffer loops run whenever there is a call. (In the discussion, I talked about running the buffer loop only when the boiler was firing, but I'll finish everything else before thinking about that.)

    The air removal works quite well, though it can't clear the radiators without bleeding them (as you would expect), and everything runs quietly after just minutes of run time after filling the system. Such an improvement from what it replaced! The pex loops have air vents on the returns, which I almost didn't put in, and those are absolutely critical. The big air separator is also important--the indirect loop, which has a regular air valve, takes days to clear itself if you don't run the buffer loop after filling the system.

    I added a circuit setter to the buffer loop, and dial it so that it matches the velocity of the primary loop. This produces a minor efficiency gain and may improve air separation.

    I wound up not putting in any check valves in the pumps. There is a bit of ghost flow through the buffer loop when the indirect tank runs, maybe a foot per minute. The buffer loop is set up run in reverse if the buffer tank/water heater is used to heat the indirect tank, so I can't put a check valve that loop. (Really, I'd like to have a check valve that will allow flow either way to prevent the ghost flow. If such a thing exists, please tell me about it!) I'll have to shut off the buffer loop in the summer--it make a big difference in terms of how hot the room gets.

    My remaining tasks:
    1) The boiler throws a fan speed error (error 61) on startup and every few days. I need to figure that out, but it's not hurting anything in the short term. Laars has been helpful, but their suggestions haven't resolved the problem.

    2) Replace the intake dryer tube with PVC.

    3) Patch all the holes. I had to make 11 of them for the ODR and two for the exhaust.

    4) Wire up the buffer tank to act as a backup heat source.

    5) I think I need a secondary low water cutoff to meet local code.

    6) Think about shutting down the buffer loop when the boiler isn't heating to avoid destroying its stratification.

    7) More insulation.