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Mod/Con Parameters

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rbeck
rbeck Member Posts: 56
I have a few questions for installation and service contractors on The Wall.
1. I am not sure what parameters the high efficiency boilers you sell have but do you normally change any of the parameters?
2. If so which ones?
3. Do you think being able to reduce the input by adjusting the boiler RPM's is a usable input?
4. Do you feel more parameter choices are better or fewer are better?
5. Is the availability of two reset curves with the option to chose which one takes priority over the other is a feature you would use frequently?
6. What do you think of not using OD rest on a high efficiency boiler?

Comments

  • Leon82
    Leon82 Member Posts: 684
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    2, Odr, max setpoint
    3, it can be,
    4, more are better. Not all houses are cookie cutter
    5, knight boilers have 3, and it has its uses
    6, not using it is a terrible idea
    Rich_49
  • hot_rod
    hot_rod Member Posts: 22,254
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    being able to electronically derate is nice, especially with a Combi
    Ramp delay is a crowd pleaser
    At least one ODR should be included

    What we really need is a 30 or 50K modcon even if it was only a 5 or 7-1 turndown.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Solid_Fuel_Man
  • Tinman
    Tinman Member Posts: 2,808
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    Lochinvar"s new WHN056 comes in at about 7:1. I've installed a couple so far.
    Steve Minnich
    Gordy
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
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    When the installing contractor installed my mod-con, he did not wish to connect the ODR sensor. He said they did not do any good. That contractor is one with whom I no longer do business. I think he really believed that. They wanted to sell me an oversized mod-con "to be safe."

    I insisted that it be connected, and he did, but left the reset curves at factory default, which was completely incorrect.

    Fortunately, I read the installation and operating manual for the boiler, and Siegenthaler's big book, so I set the reset curves (one for each zone in my case) and they are quite different (no surprise, since one zone is baseboard and the other is radiant slab at grade). The defaults put water at much too high a temperature throughout the entire range from 0F to 70F outside temperature.
    Tinman
  • Tinman
    Tinman Member Posts: 2,808
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    The more parameter options the manufacturer gives, the better in my opinion. The building is part of the system and no two are exactly alike. The X factor is the inhabitants of the building. For some people, energy savings is their primary concern so I can get really aggressive with the reset parameters. Others, could not care less about squeezing every ounce of energy out. They just want it to be as warm (even hot) as possible. Always. For those, I'm much less aggressive.
    Steve Minnich
    CanuckerGordy
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    In addition to the four ODR parameters, I've tweaked:
    CH Anti-Cycling time
    Heating capacity
    DHW capacity
    CH Step Modulation

    I can think of a few additional parameters I'd like to have access to but are not included in my boiler's install menu.

    A second (user programmable) ODR curve would be great for conditions below design day temps.

    Not using the ODR sensor?... poor choice.
    You don't need 180F SWT when it's 50deg outside.
  • kalex1114
    kalex1114 Member Posts: 104
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    My installers when they came over to configure heating side of things had it set to 180f at 35deg outside. I adjusted it later
    Now just need to dial in ramp delays on mine
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    One of the big problems seem to stem from the fact that the output of std fin-tube is so unpredictable at low condensing supply water temps that there's almost no way for an installer to accurately "dial in" a custom ODR curve that will not prove problematic under certain weather conditions. In the end it seems many installers just leave the ODR curve at factory default (which is generally waaaaaay too hot) and move on to the next job.

    How do the pro's here set up their customers ODR curves without making many return trips to the home because the curve can't keep up on a cold windy day?
  • Canucker
    Canucker Member Posts: 722
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    If it were me, I'd do it the same way that car manufacturers explain how to use their options. RTFM. You bought it, might as well learn how it works
    You can have it good, fast or cheap. Pick two
    Gordy
  • kalex1114
    kalex1114 Member Posts: 104
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    Canucker said:

    If it were me, I'd do it the same way that car manufacturers explain how to use their options. RTFM. You bought it, might as well learn how it works

    Thats what I ended up doing.
    Canucker
  • Gordy
    Gordy Member Posts: 9,546
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    While I agree @Canucker the manual for the Average HO can be a bit confusing. More so how to use the anti cycling, ramp delays etc. knowing how to change the parameter, and how to enhance the system with it are two different things.
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    ^ agreed!
    The manual for my HTP mod-con only mentions the four settings that make the ODR curve... no explanation of the theory behind the idea of ODR curve or how to even begin calculating starting points for experimentation.

    Internet connectivity from tech support to the boiler where they could tweak the ODR curve remotely for the customer might help, but a page of good info/theory in the manual would help too.
  • Canucker
    Canucker Member Posts: 722
    edited January 2018
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    @Gordy Could you say there's online support and give them the heating help website address? I've found it's been the best resource for me. :p
    You can have it good, fast or cheap. Pick two
  • Gordy
    Gordy Member Posts: 9,546
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    Yes you could.
  • Brewbeer
    Brewbeer Member Posts: 616
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    I'm still dialing in the ODR curve (two years after install) trying to run constant circulation. The baseboard output really drops when SWT drop into the high 90s. On the mild days, sometimes inside temps fall a couple degrees behind.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread: http://forum.heatinghelp.com/discussion/154385
    System Photo: https://us.v-cdn.net/5021738/uploads/FileUpload/79/451e1f19a1e5b345e0951fbe1ff6ca.jpg
  • kalex1114
    kalex1114 Member Posts: 104
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    I have ConXus board in my lochinvar and I offered to provide connectivity to the company that installed it. Guy who was doing "programming" on my unit looked at me like I was an alien and said "nah, we don't need this"
    I offered him ipad to do intial programming, he also declined and spent an hour clicking joystick on the controls.
    It seems to me that their sales staff is really pushing mod/con hard but their service department is lagging behind in training and support of new technology. or they are doing everything possible not to have call backs.
    I was going to install modbus board that lochinvar provides, they told me straight out "if you install this we can't support it if you make any changes to the boiler and break things". Never mind that I was going to use MODBUS as readonly not read/write mode