Click here to Find a Contractor in your area.
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/.

Primary/Secondary mod con boiler issues

I just installed a lochinvar nobel 199 combi boiler we a primary/secondary configuration with 5 zones. While tuning the ODR I was getting system water temps that don't make since to me so though someone here might know what's up.

 The issue I'm seeing is my boiler outlet temp is 177, my inlet temp is 169 (primary loop), my secondary manifold supply temp is 157 (system temp), and my  secondary monidold return temp is around 151.

The issue I'm having understanding is how is this possible. If I'm over pumping on the primary side you would expect to see the secondary manifold supply temp the same as the boiler outlet temp. If I'm over pumping on the secondary loop you would expect to see the boiler inlet the same as the boiler manifold return.  Can someone explain what's happening?! 

for the boiler inlet and outlet Im getting that from the boiler control panel, for the secondary loop manifold I'm getting that from a boiler supply temp & a mechanical t&p gauge, and for the secondary loop manifold return I'm getting that from only a mechanical T&P gauge.


Lastly let me know if you see any glaring issue with my install. I realized I didn't level 12" above the zone circulators as dictated by taco so I will be fixing that on a warm day by dropping the mainfold down a little. Also the 5th zone is not hooked up yet as that will be a future garage as and I haven't hooked up the condensate neutralizing piping.

The boiler is running and heating but I just can't make since of the #s

Comments

  • Tom_133
    Tom_133 Member Posts: 735
    If your taco pumps are pumping up, then you got the supply and return backwards on your primary secondary. The supply is on the left the return is on the right. At least thats my memory of which is which
    Tom
    Montpelier Vt
    Jeff_SudaGroundUpAlan (California Radiant) Forbes
  • Jeff_Suda
    Jeff_Suda Member Posts: 3
    Holy crap you are correct... How did I messs that up and not realize that until now!!!... Time to flip the pumps until a warmer day when I can fix it

    @Tom_133 thank you Soo much!!!!! I have been banging me head trying to figure this out for hours.
  • hot_rod
    hot_rod Member Posts: 14,785
    What type of heat emitters? that you are running the boiler that hot.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • GroundUp
    GroundUp Member Posts: 1,175
    Yes, the boiler loop is piped backwards and if you simply flip the pumps then the secondary will be backwards and you'll be pumping toward the expansion tank. Just fix it right and switch the boiler piping around
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,980
    Lots of nice pro press scrap copper too bad.

    Everyone occasionally pipes something wrong occasionally. I had a guy helping me pipe a warm air gas furnace . I was doing the gas and he was doing the pvc flue and intake.

    he had the flue on the left and intake on the right in the basement. He went outside and put the terminations on the wrong pipe.

  • hot_rod
    hot_rod Member Posts: 14,785
    The temperature to the zone circulators will change based in the gpm, or how many circulators are running.
    Assume the boiler has a single speed, non variable circulator 15 gpm flow perhaps?
    If one 2 gpm circ is running the mixed temperature will be different compared to when 4 circs are running, may be an 8 gpm load.
    With some data or assumptions you can calculate or predict what the temperatures will be. Usually one side has a larger flow rate, on some occasions the boiler flow and the distribution match exactly, then there is no mixing and expect to dee boiler outlet temperature at the distribution.
    Are you using the boiler supply sensor to maintain a temperature to the secondary loop? the boiler can modulkate attempting to maintain a "target" SWT.

    I think you have what is referred to as reverse injection, which can work if you have the flow rate required. Tekmar has a good explanation, shown in their essay sheet attached. See by their formulas and the color and size of the flow arrows what is going on with the direct or reverse injection.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jeff_Suda
    Jeff_Suda Member Posts: 3
    @hot_rod baseboard fin tube but that was only temporary until trying to get it to work. Now that the flow direction is correct the temps are way down

    @GroundUp thanks for the incite.  I'm definitely going to fix it but with news years unfortunately my plumbing supply is closed until the 4th and I need some new unions and primary/secondary tee. Unfortunately flipping the pumps is what I have to do for a few days.

    @EBEBRATT-Ed the one downside of pro-press...when u screw up u waste a ton of fittings... Luckily it looks like I can just have the primary loop cross itself so I only have to scrap the unions, tee and a few elbows... Most everything else hopefully can stay the same.... I still can believe I did this
  • neilc
    neilc Member Posts: 1,298
    can we see a picture of the fix under the boiler,
    please?
  • BillyO
    BillyO Member Posts: 265
    the right side tapping of the boiler is the CH outlet?
Sign In or Register to comment.

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!