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Burnham Alpine 105 - DHWP - ?

Slowhand63
Slowhand63 Member Posts: 80
edited January 2021 in THE MAIN WALL
Burnham Alpine 105B boiler supplying indirect domestic HW tank and multi-zone radiant. When radiant is calling for heat for a long period of time, domestic HW goes cold. Controller setting is "DHWP", which should give priority to the HW vs. the radiant - no? Turning the radiant zones off immediately directs heat to the indirect tank. Appreciate suggestions/ideas/advice.

Comments

  • Zman
    Zman Member Posts: 7,611
    How is this piped?
    I have seen heat system pull heat from DHW indirect due to a missing check valve,
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Slowhand63
    Slowhand63 Member Posts: 80
    There is a check valve in the system on the radiant leg, but not on the DHW indirect. I should also note that this issue occurs only when it is really cold outside (likely when the radiant is running for long periods of time). It seems that although DHWP is enabled, DHW is not truly the priority.
  • Zman
    Zman Member Posts: 7,611
    If the radiant is able to pull heating water backwards through the indirect, that may be your problem. A typical DHW priority has a timeout feature so the house won't freeze. Just guessing here without knowing how yours is piped and controlled. I picture taken from a distance where the whole system is visible would help.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,214
    Your boiler controls DHW priority by turning off the system pump and energizing the DHW pump. This works as long as both pumps are wired into the boiler. If the system pump is wired to an outside control without priority, priority won't work.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • Slowhand63
    Slowhand63 Member Posts: 80
    Both circulators are wired to the boiler, but I am starting to wonder if one of the circulators is not working. When I found the issue last night I turned off all of the radiant thermostats, but at the control panel one was still calling for heat (it must have a time delay?). I became impatient and powered down the boiler/controls. Upon power up the DHW was now being fed, and the circulator seemed louder. Could the circulator be hanging up? - though cycling the power should be no different than sending it a signal to run...
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,214
    edited January 2021
    Are you zoning with pumps or zone valves? What brand is your zone control? Taco? Caleffi? Argo?

    You shouldn't have a time delay on your zones. They should all turn off once the thermostat is satisfied. Post-purge is possible?

    Regardless of zoning, the boiler should switch power to the DHW pump on a call.

    Double check the boiler coding:


    Boiler manual:
    http://bostonheatingsupply.com/Burnham/Burnham Alpine I&O Manual.pdf
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • Slowhand63
    Slowhand63 Member Posts: 80
    Update: while calling for DHW I turned the radiant thermostats on. Both circulators ran, and I could see the "call for heat" signal (yellow led) for the radiant - but the valves (wirsbo actuators) remained closed. After a good 5 minutes (maybe more) the zone control (Uponor A303004) led went from yellow to red and the valve opened. BUT, the DHW tank (Burnham Alliance) was still calling for heat, and BOTH circulators continued to run (?). Last night I walked through the HMI and confirmed that DWH Priority was enabled,so I don't think that's the issue.
  • Slowhand63
    Slowhand63 Member Posts: 80
    For clarity - the "delay" I've mentioned seems to be from when the thermostat is turned on or raised, and the lag until I see the signal on the zone control module.
  • Slowhand63
    Slowhand63 Member Posts: 80
    Attempting to attach a rough schematic of my system...
  • Slowhand63
    Slowhand63 Member Posts: 80
    Looking at the schematic I just drew up, I realize that I don't fully understand the system operation. I had not realized that there is a small Taco circulator just before the radiant manifold. The (Grundfos) circulator at the very top (right side) of the drawing is the one I was referring to as the radiant circulator; the one below it is for the DHW...
  • Ironman
    Ironman Member Posts: 7,550
    That piping doesn't look right. Why does the return from the radiant manifold reconnect to the supply in the secondary loop? This may have nothing to do with your problem, but I can't see how it can function correctly.

    Can you post some pics of your zone panel wiring?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Slowhand63
    Slowhand63 Member Posts: 80
    Ironman - great question, and all I can say is I have no idea. The system has been problematic from day 1, and I've considered having it pulled out and starting over many times. Re. the zone panel wiring - I'd be embarrassed to... it's a bit of a mess, but the zone controller is only for the radiant thermostats and controlling the actuators (thermostat input, actuator output, and power). did you want a photo of the Sage controller wiring?
  • Slowhand63
    Slowhand63 Member Posts: 80
    To be fair, the installer said it was piped that way to maximize efficiency...
  • Slowhand63
    Slowhand63 Member Posts: 80
    Zone controller wiring
  • Ironman
    Ironman Member Posts: 7,550
    What's controlling the primary circulator?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Slowhand63
    Slowhand63 Member Posts: 80
    I assume the Sage controller of the Alpine
  • Ironman
    Ironman Member Posts: 7,550
    This is what your piping should be like.

    I tried to make it simple and to resemble your drawing so it would be easier to follow.


    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Ironman
    Ironman Member Posts: 7,550
    There appears to be no connection between the zone panel and the boiler to call it to heat.

    The order should be: a thermostat(s) call the zone panel to open an actuator(s); once the actuator is open, it signals the zone panel which in turn signals the boiler there's a call for heat;the boiler starts the primary circulator and its burner. If there's a domestic call, that overrides the space heating call for up to 30 minutes, during which time the primary circ is de-energized.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Slowhand63
    Slowhand63 Member Posts: 80
    Ironman - thanks. That's incredibly helpful. I'll have to see what mods I can make. Considering it's been piped like that for almost a decade, I don't think that's the source of the current issue, so I'm going to try to resolve what's going on first. Thanks again - that was clearly above and beyond
  • Slowhand63
    Slowhand63 Member Posts: 80
    Thanks. I have to step out for a couple of hours, but will review the wiring - and what connections exist between he zone controller and the Sage when I return. I also plan to swap out one of the circulators that is making noise (I have a spare on the shelf).
    neilc
  • Slowhand63
    Slowhand63 Member Posts: 80
    Took some photos of the uponor to alpine wiring. On the uponor it's the green and blue wires, which are then spliced to red and white. Not sure which red and white they are, but it is connected to two of the 4 top terminals as it enters the alpine - see photos
  • Ironman
    Ironman Member Posts: 7,550
    It looks as though the red wire going to "DHW Temp switch" has slipped out of the terminal. Notice the indentation on it from the terminal screw.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Slowhand63
    Slowhand63 Member Posts: 80
    Ironman - thanks. I will check. I could see that it seemed like it was pulled out (or too much insulation was stripped) so I gave it a small tug and it seemed secure - but I will re-secure it to be sure.
  • Slowhand63
    Slowhand63 Member Posts: 80
    I checked the boiler connections - they are all tight. Did not change the noisy circulator since we got about 1-1/2' of snow and didn't want to chance having an issue and not being to pick up parts, etc. I did step through the "Pump" section of the display and found the following: "System Pump - Run pump for: Central Heat, No Priority"... then "Boiler Pump - Run pump for Any demand"... then "Domestic Pump - Run pump for Boiler piped IWH"... and lastly "Domestic Hot Water - Priority Status: Enable. Countdown 3436 sec (and counting down)".

    I currently have all of the radiant thermostats OFF to ensure we have hot water. Appreciate any additional suggestions on what I should be looking for. Thanks
  • Ironman
    Ironman Member Posts: 7,550
    Some pics of your piping would really help to see how the pump logic should be set up.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Slowhand63
    Slowhand63 Member Posts: 80
    Will try to post some photos tomorrow. I'd hoped the rough schematic I provided would help in this regard, but if photos are preferred I can make that happen.
  • Slowhand63
    Slowhand63 Member Posts: 80
    Changed out the noisy circulator today. Upon removal found a ~ 1/4" dia spring sticking out about an inch from one end - I assume this is the check valve that broke. Fished around inside the pipe for the plastic end and did not find anything (it has to be in there somewhere - right?). In any event, installed the new circulator, but now no HW. The boiler seems to be working fine, One leg of the indirect to the tank is hot - the other is cold. I'm thinking the system is air-bound. I cracked several of the purge valves and got a steady flow of water. Not sure where to go next....
  • Slowhand63
    Slowhand63 Member Posts: 80
    Also removed the center silver plate with a flathead - got a very small burst of air and then water began to trickle out. I wouldn't think this tiny bit of air could prevent water movement.
  • Slowhand63
    Slowhand63 Member Posts: 80
    I am posting a couple of pics of the system (the dwg is not to scale and may not be 100% accurate). By closing the boiler feed purge valve and isolating the radiant system I was able to get the indirect hot. If I open the valve with the system running it sounds like a lot of turbulent flow - likely due to air.
  • Slowhand63
    Slowhand63 Member Posts: 80
    Some more. Note the closed boiler feed purge valve closed in the last photo
  • Ironman
    Ironman Member Posts: 7,550
    The piping is so convoluted that I'm having trouble following it. Can you post a couple of pics that clearly encompass all of it instead of portions of it?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Slowhand63
    Slowhand63 Member Posts: 80
    The boiler room is tight - this is the best I could do. Planning to put the old circulator back in. As mentioned previously, it has a spring hanging out of one end. I assume that's a damaged check valve. Can I break it/pull it out with a needle-nosed pliers without the risk of damaging anything? First problem is to resolve the DHW issue (likely air bound). Then back to the radiant. Oh, and the PRV and BFP are both leaking a bit (priority 3 and 4).
  • Slowhand63
    Slowhand63 Member Posts: 80
    Put the old circulator in. Started the system and it seemed to be running fine (both the supply and return to the water tank were hot on startup). Will check it tonight and the morning to make sure it is working as it should. Removed the broken check valve from the circulator before reinstalling and it is a bit quieter. Ordered a new backflow preventer as the existing one is now weeping. If HW is all okay tomorrow, I'm back to trying to get the radiant to work. Reminder that this all started because when the radiant is running the indirect HW tank goes cold, though it is calling for heat (and DHWP is enabled on the Sage 2 controller).
  • Slowhand63
    Slowhand63 Member Posts: 80
    I know this has been a long thread, but I am still at a loss as to why the indirect HW system doesn't take priority when the radiant heat is on, even thought the boiler has DHWP enabled. Any/all suggestions greatly appreciated.

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