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Topic Update :: return>supply, pictures added

Macaroni12 Member Posts: 9
edited January 2022 in Radiant Heating
Update: I think my issue has to do with zone 3 driving up return temp, or supply sensor in wrong location. Pictures and more detail below. You guys are very helpful. Thank you

Hi all - New homeowner here with a Weil Maclean Ultra 155 Boiler System (3 zone) -- Home was struggling to stay >62 degrees on days <20 degrees outside - Turns out circulator pumps were not zoned properly. That was adjusted and home has been much warmer, however today was the 1st true test and the first floor was floundering around 65 degrees this morning- Has since warmed up as the temp increased outdoors.

The house is raised ~7ft off the ground (exterior foundation walls are not insulated, ceiling of crawlspace is) and the boiler pipes run across the ceiling outside of the insulation. They're however, currently wrapped in foam pipe insulation -- Suspect that those pipes are losing quite a bit of heat when the temp drops below 20 -- Short of insulating the whole walk in crawlspace, would better fiberglass insulation help? Raising the water temp on cold days?... Or is none of this an issue and i'm back at square on of boiler setup, which I realize required quite a bit more information .. Just trying to get a sense of if it could be a meaningful variable.

Appreciate your guidance.


  • Larry Weingarten
    Larry Weingarten Member Posts: 2,955
    Hi, Insulation is rarely applied so the heat loss is negligible. Best would be if you could have a look at the lines with an IR camera, so you could clearly see if and where the heat is escaping. Depending on the temperatures involved, you might be able to use polyethylene, rubber, or fiberglass insulation. I've even put two layers of foam insulation on some piping, staggering the seams, to be certain of greatly reduced heat loss. Pay special attention to any air leaks at insulation joints or seams. Hope that helps!

    Yours, Larry
  • bburd
    bburd Member Posts: 646
    What is the supply water temperature at the boiler? Do the controls adjust that temperature based on the outdoor air temperature (outdoor reset, or ODR)?

  • Macaroni12
    Macaroni12 Member Posts: 9
    supply  temp is dropping below 150 when all 3 zones are on and I get a return>supply error when only 1 zone is on. 

     I’m back to thinking it’s a settings issue. ~20 degrees today and can’t get the whole house above 67.

    Boiler seems to default to priority 3 no matter how many zones are calling for heat. Priority 3 = circulator pump 2. Ignores pump 1 and 3

    priority zone 1= all 3 circulator pumps

    Priority zone 2= pump 2 and 3
  • PC7060
    PC7060 Member Posts: 961
    Make sure it’s not a vented crawl which is typical if the walls aren’t insulated and the floor above is. 

    Personally I’d insulate and seal the exterior walls and create a conditioned space. You’ll find the space above become much more comfortable and any loss from the radiator pipes will remain in the home. 
  • Macaroni12
    Macaroni12 Member Posts: 9

    here’s some photos of the setup which I suspect will help. Much appreciate ld

  • Macaroni12
    Macaroni12 Member Posts: 9
    I have a tankless heater. 

    I don’t know if at a point there was a DHW zone hooked up to this. I just bought the house

    4 zone switching relay, though only 1-3 seem active. 

    i just raised min on time for priority 3, given that seems to be driving all 3 zones (including my primary) 

    zones 2+3 are OK temp wise, though zone 3 not perfect and zone 1 is currently 61 degrees (set to 70)

    seems like zone 1 doesn’t have its own primary? Trying to figure out how to debug primary setting zone by zone 

    thank you for your guidance so far
  • Macaroni12
    Macaroni12 Member Posts: 9
    edited January 2022
    Update. After another night of low teens high single digit

    zone 1 is now 57
    zone 2 is now 66
    zone 3 is now 66

    this thing is locking itself out every 10-15 minutes stating return temp higher than supply

    oddly as I stared at the boiler from 1-4 am, the supply temp never drops below the return temp on the he screen. Just on the diagnostics screen 

    to recap, boiler only seems to be using priority 3 for a 3 zone system. At this point I have circulator pump 2,3 on and reduced flow to 75. Can’t seem to do anything to avoid return above supply lockout 
  • Macaroni12
    Macaroni12 Member Posts: 9
    I think my return and supply sensors are swapped.

    the “on screen” is showing proper supply of ~150 and return of ~130

    And at the exact time of lockout, the lockout diagnostics screen shows supply of ~130 and return of ~115

    could someone help me confirm this? Seems to jive but not sure

    Really appreciated from helpless new homeowner 

  • Macaroni12
    Macaroni12 Member Posts: 9
    edited January 2022
    To follow up, I figured out how to follow the sensor wire to the connection. It looks wired properly

    it seems zone 1 will run completely fine if alone, adding zone 2 doesn’t bring an issue. As soon as zone 3 is added my return temp jumps

    Supply temp sensor location is right after the split for the 2nd zone. Should it be just after the supply outlet before any split. In theory would think this is a higher reading that could keep up with higher supply?

    or I guess the real question is why is zone 3 driving up my return temp 

    zone 1 is first floor radiator
    zone 2 is second floor baseboard (except master)
    zone 3 is finished attic baseboard and master 

    temp sensor pic below 

  • Macaroni12
    Macaroni12 Member Posts: 9
    Alright. I just ‘nudged’ the sensor in its current location to see if it was a contact issue. Supply temp immediately shot up ~40 degrees and is in line with boiler output. 

    You have got to be kidding me…

    EBEBRATT-Ed Member Posts: 13,422
    Take some more pictures from farther back. Pump #1 looks like the boiler pump unless it's piped wrong
  • Macaroni12
    Macaroni12 Member Posts: 9

    Thanks. Better? Are the green circulators the “pumps” or just zone control? If so I’d think all three should be on?

    Currently running on pump 2 for what that’s worth.. 
  • PC7060
    PC7060 Member Posts: 961
    Are those flexible couplings rated for use on HVAC venting?The intake isn’t a concern but I’d switch out the exhaust to an approved coupling.