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Is there a Lochinvar Knight settings tutorial? Esp. to increase modulation.

Is there tutorial for Lochinvar Knight boiler control settings?

That would be a big help to me.

OR should I just buy the control software (CD and cable) ASAP, and things will then soon be much clearer?  :-)

A specific question I now have: how to force (encourage?) the Knight to modulate more -- lower and longer firing.

How can I COMMAND it (settings),

and/or how many ways can I CAJOLE it (design, installation)?


The Knight's firing seems aggressive.  

Is default to aim for 100% firing?  

(I know that without software this can be tamed just a bit with ramping parameter G3.)

Does the Knight then modulate only as far down as needed to match ODR curve, or some other Knight rules about I/O temperature rise?

Pushing down the ODR curve does not seem sufficient to really promote modulation, but I should try again.

And I do dearly wish I knew what triggers the end of the boiler's cycle.  

Small loads (insulated bungalow, with CI radiators) leads to short firings,

more frequently than I would like.

I have read and re-read the Knight manual, which is sparse; and I made notes,

and tried to reconceptualize the material to suit my brain.  ;-)

I have taken the one-day Lochinvar Knight class.

And have paid attention here over the years, to the best of my ability.  ;-)

Thank you!


  • Paul Rohrs_14
    Paul Rohrs_14 Member Posts: 80
    edited March 2011
    Smart System Features


    When hearing about cycling issues on high mass systems it makes me wonder about system sensor placement and the flow thru the boiler but we will work with the information provided.

    To answer your question directly, you don’t have a DIRECT means to change the modulation rate of the boiler. 

    You mentioned you wanted the boiler to modulate “more, lower, and longer”.  To accomplish this you have several means available.  As you talked about smaller loads with CI radiators and the potential for short cycling, the 1st best means is to add mass to your system as in a buffer tank.  Normally a CI rad system has a high enough water volume so that the low-mass boiler doesn’t operate with erratic behavior so I can’t really decipher if you have a low mass system with high mass radiators or what, but a buffer tank can always take up the slack for the short-cycles you are trying to avoid.

    A second possibility is to engage the ramp delay feature.  This applies only to space heating mode and will in effect, limit the firing rate for a measure of time.   Both the rate and time are adjustable so this will give you added response time for the boiler firing rate reacting to the system.

    “Triggering the end of the boiler cycle” wouldn’t be the terminology I would use but I understand what you are driving at.  Upon a call for heat, the boiler will fire, and provided the outdoor sensor is utilized, a target temp (based on current ambient conditions) will be established.   Interacting with that setpoint are two adjustable parameters.   They are the Offset and Differential.  See attached JPEG.  The Offset is the temperature that you can adjust that the boiler and then allow it to travel over the setpoint.  I.e. - if target temp is 150 and you have the offset for 10, then the boiler will then be allowed to fire up to 160F.   The differential, (again, also adjustable) is the temperature difference needed to fall below the setpoint plus the offset.  If diferential is at 25, then the boiler will come on again at 135. 

    Setpoint 150 + 10F Offset = 160  minus the differential (25) then equals 135F and at that point the boiler will fire provided the call for heat has not been met.

    You may consider making a slight increase for your Offset which would allow the boiler a little more response time.   Be advised that this adjustable temperature can pose detrimental side effects if set to high in that it could surpass a manual reset high limit temperature or other temperature limiting devices you may have field supplied and installed. 

    One other tool you have available in the Knight Control Arsenal is that of Anti-Cycling.  You can program in a length of off time needed before allowing the boiler to fire again.

    To recap, look at adding mass, try the Ramp Delay feature,  make small incremental changes to the Offset, and finally, deploy the Anti-Cycling feature.

    The Smart Control platform is fully loaded and really equips you to detail your system and provide minor corrective actions without any piping and equipment changes.   Pretty terrific if you ask me…but of course, I am only SLIGHTLY biased.

    As always, Lochinvar is poised and ready to answer any system related questions you may have.   Pictures are always a great reference point for us as it pertains to system design questions but we look forward to hearing the results of the tweaking you do.


  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    I might add...

    that the software that comes with the new Smart System is extremely user friendly, and allows you to control the adjustable parameters to the point that you can make the boiler stand on its head and spit wooden nickels.

    OK, I may have overstated the capabilities just a LITTLE bit, but from actual field experience, I can tell you that you can fine tune the connected appliance(s) to the Nth degree, and NO ONE else is offering this kind of access on the open market that I am aware of.

    I hooked my boiler in the mountains up to the desk top PC that will be controlling my home up there. I ran into a slight problem. I attempted to extend the USB cable from the mechanical room to the PC's location using 18/2 multi strand shielded cable, and couldn't get it to communicate at all. Then, through research, I found out that USB cables are not meant to be longer than 6' in length. I guess my 25' run may have violated this rule. No problem, additional research caused me to find a USB "Repeater" cable that will allow you to install USB cables up to 25 meters in length (using 25'ers)

    $25.00 later, it works like a charm now. And any time my heart desires, I can bring up the graphics program, and see how the little Lochy is working, and adjust and or tweak or just simply watch what's going on.

    Great stuff there Lochinvar. A true wet headed geeks dream come true :-)


    There was an error rendering this rich post.

  • aemeeich
    aemeeich Member Posts: 16
    LCD display

    A bit off topic here, but do you find the LCD on the new Smart System hard to read?

    The contrast is so low and the viewing angle so narrow that it is really hard to read the display.

    I love the Knight and as mentioned all the adjustable parameters, but find the display very disappointing.
  • Kal Row
    Kal Row Member Posts: 1,520
    i havent posted in a long time but here goes...

    use "ramp delay" which slows the ramp up timing of the boiler

    u get a few steps and u can limit the max firing percentage

    i usually keep it at 20% for 2 min  then ramp up 20 every min

    also for a small load i set a deeper offset - so the boiler slows down when it gets to setpoint-offset and approaches the setpoint at a slower rate

    these two together should keep u from short cycling - after that u need a buffer tank

    a trip to Lochinvar university at the factory is well worth it - been there and am going again

    i like the new display and  haven't had problems reading it and i like the knob input, perhaps because i am a pilot and we have that on our radios and navigators - so u can count clicks as u r turning so u can keep ur eyes on the attitude indicator when ur flying in instrument conditions - and can only afford to glance over to the radio or gps for a sec - that is, if u want to keep the aircraft upright, and not spiral out of control ;)
  • GreggShadduck
    GreggShadduck Member Posts: 9
    Thanks, Mark -- software it is

    Thanks, Mark, for your help.

    I will sign up for the head-standing, nickle-spitting deal, which sounds attractive, and did not come WITH my Knight about 2 years ago.  An add-on, and well worth it, it seems.

    It must be true that interactive "playing" (via software) with the system should advance my inadequate knowledge.  :-)

    Thanks again.
  • GreggShadduck
    GreggShadduck Member Posts: 9
    Ramping it is

    Thanks for making sure I focus on ramping.

    If I remember correctly, any real control of this feature is via software, not via the menu system... whether by button (my older one) or via rotary control, which you make sound very attractive!

    Thanks again!
  • rlaggren
    rlaggren Member Posts: 160
    from the BTDT department

    When you fine tune settings (computer, engine, appliance, whatever) record those settings (all of them) and the reasons for such. I try to leave the record at the point of use as well as keeping a copy for the file. For some strange reason I can _never_ remember why I made a particular setting and it's way, way easier to look them up then it is to deduce them again after a hard reset or replacing a controller or noticing something isn't set at the default and wondering if that could be the source of a problem...

    Sad experience makes me conclude it's well worth any time it takes.


    disclaimer - I'm a plumber, not a heating pro.
  • GreggShadduck
    GreggShadduck Member Posts: 9
    Yes, time for settings work, continuous circ, buffer

    Thanks very much, Paul, for your prompt response, for your time, and for your help.  

    I appreciate it, and am just now catching up after competing for the single PC here.

    I apologize that I am slow to respond... to collect my thoughts, which have kept scattering.  

    Your response prompted study, and I learned something.  Thanks!

    I apologize, too, for lumping three questions.

    They were:

    1. Tutorials, or other elaborations on Knight documentation.

    I would still love to hear if there is something more online at Lochinvar, or used in their classes, or at some other site, or...

    2.  Software -- its value.  About which we get enthusiasm.  OK!

    3.  Ways to promote modulation in the Knight.

    I still wish a fuller understanding, but sure expect it is time for ME to put in more time to run and record trials.

    In response to your comments:

    These are probably famous last words to say "I plumbed it as directed in the I and O

    manual."  ;-)  e.g. Where the Knight manual said, e.g. Thou shalt use 1" near-boiler piping (No matter the size of the boiler, or flow?) I did it.  Thou shalt only plumb it P/S in this fashion.  (No mention of allowable/reliable buffer configuration.)  Well, I did it.  etc.

    (And thanks for the suggestion of the photo.  Maybe my daughter can show me how to do it.  Old dog, new trick.)

    So, yes: there is short near-boiler piping, connected through closely-spaced tees into the system (house-heating) loop, with system monitor (thermocouple) mounted 4 inches downstream on this loop.

    This is the old-style Knight 80 (no support of variable-speed circulators, which sounds cool)

    Installed now 2 winters, in a 1-1/2 story bungalow,

    which had an old gravity boiler (1,000 pounds of cast iron scrap removed, plus jacket water) --

    with standing CI rads,

    and cast iron radiation actually increased a bit, with standing CI radiators and added CIBB.

    TRVs added to all (though now just run full open, when I forsook continuous circ)

    and a kludge DPBV was implemented.

    You said "buffer," and that has been on my mind, and is now on my worktable.


    Your couple examples (Offset and Differential), and comments by others on Ramping, were enough to clue me in, and send me back to the manual, where I (gasp!) learned something.

    Namely, that I can improve control methods, from crude to finer (with head slap, after returning to the manual): a room thermostat is unnecessary; instead use flow, setting, and sensor.

    I had simply been using a room thermostat --> on/off call for heat --> Knight controller uses default settings (or as modified).  The result: on/off, with a variable overlay of modulation.

    It is now clear that continuous circulation may have benefits in smooth heat delivery,

    BUT also provides a feedback loop:

    [no thermostat]

    continuous circulation --> flow past system sensor --> Knight operates according to settings.

    The result: Proportional response, until demand for heat falls below Knight ability to modulate, which finally results in on/off operation, until repeated.

    Comment: Knight setting H2 (SH Source) has a value = "thermostat," (=1)

    which I took (I thought reasonably) to be a switching device: on/off.

    Wrong!  This value shifts control to a sensor: system sensor.  

    As you well know.

    Now, yes, I will explore these Knight settings you mentioned to encourage modulation:

    B4  Offset and B5  Differential

    G3  Ramp delay -- using software

    F9  Boost time and F8 Boost temperature

    A question, please:

    Is the Knight descined to become less aggressive in firing as it exceeds the setpoint and closes in on the higher point set by offset?

    Thanks again for your help.
  • GreggShadduck
    GreggShadduck Member Posts: 9
    Fat fingers, poor threading -- sorry, Paul

    I am sorry, Paul, that I seem not to have properly replied to you so that my response would be sure to get to you; namely thanks!

    It lies elsewhere on this thread.
  • Paul Rohrs_14
    Paul Rohrs_14 Member Posts: 80
    edited April 2011

    As it pertains to tutorials, VIP Contractors have free access on our Knightheatingboiler.com site to multiple resources.   We have two presentations available titled, "Smart System Parameters" parts I and II.   They are great at illustrating all of the control options available to you with our Knight boilers and other products that feature our "Smart System Control".There are several other things available at that site that contractors find valuable, but out of respect for Dan's site, maybe I can walk you thru these off-line and directly.Feel free to get ahold of me via prohrs@lochinvar.com and we can discuss all of the great things Lochinvar is doing to raise the bar in the industry.Regards,Paul
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