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Head scratcher, (for meπŸ™‚)

icy78icy78 Posts: 243Member
Ok guys, youll need to reference the pics below. This has been a trouble system for years apparently.
Issue is no flow thru various zones randomly. Altho zone #4 is fairly consistant with no flow.

The near boiler piping looks wrong to me but i cant place it.

I repiped so the heating pump was pumping into the supply header. (Was on return side) Added spirovent
I verified flow thru each zone using washer hose on sink spigot and power flushing thru the loops ,forward and backward.
The only way i could fedl the end of the #4 loop warm up in normal operation was with the boiler , and its pump off, and the DHW loop off. Then when i closed the return piping valve labeled "this valve" that loop would heat ,along with the others.
Loop number 3, the highest coil would air lock often.
I think there may be a few things wrong here and maybe its simple, but I am confused!

Heating pump can run any time, even when DHW pump is on. It didn't seem to make any difference.

For what its worth, id say the boiler is far to big. Altho it may be sized for DHW. Its a camp and gets heavy use at times. 20 boys and girls showers. Building is only about 2000 sq ft tho.

Comments

  • icy78icy78 Posts: 243Member
    Sorry about the pics. They mean more to me I guess as i used them to remember the layout.
  • ZmanZman Posts: 4,688Member
    edited March 16
    I think your immediate problem is a lack of flow checks on the dhw and heating circs. I am not sure why the ball valves are closed or partially closed but they should be open fully.

    Why would you put a mixing valve on a mod/con boiler? I would repipe is like this and set the boiler on an outdoor reset curve. Don't forget the flow checks.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • ZmanZman Posts: 4,688Member
    The pressure drop through the mixer is not helping things either.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icy78icy78 Posts: 243Member
    > @Zman said:
    > The pressure drop through the mixer is not helping things either.

    I wondered about that. When the other pumps are running, i think there is not enough pressure difference between the supply and return. Caused by the mixing valve? So when the other flows and resulging pressures are turned off (manually) the only restriction is the MV, and that is equal on both sides?

    Id guess the MV is there because of the DHW and the need to heat at the same time. However, the MV is set at 155 so in that case its probably not needed.
  • icy78icy78 Posts: 243Member
    @ Zman. Im thinking just cut out the mixing valve.
    Comments?
  • SuperTechSuperTech Posts: 935Member
    I say definitely lose the mixing valve. The layout that @Zman provided should work nicely. The mixing valve is completely unnecessary.
  • icy78icy78 Posts: 243Member
    @Zman. My apologies. Your layout didnt show at first, altho more likely that I missed it due to the hour! 1:30am.πŸ™‚. I see it now after @SuperTech referenced it.

    Today I showed my 11 year old son the piping, cause we were out running on-calls.
    I told him i think I'll do this.... comes out the same as your pic.πŸ‘

    Thanks for the input
  • Harvey RamerHarvey Ramer Posts: 2,173Member
    Might want to pull the spirovent apart and clean it while you at it. If a loop is gettibg airbound, it's probably not working right. Not uncommon to see the vent head clogged with flux when people don't clean the system after installation.
    Ramer Mechanical
    ramermechanical.com
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  • icy78icy78 Posts: 243Member
    > @Harvey Ramer said:
    > Might want to pull the spirovent apart and clean it while you at it. If a loop is gettibg airbound, it's probably not working right. Not uncommon to see the vent head clogged with flux when people don't clean the system after installation.

    Spirovent is new yesterday Harvey.
    I did not know that about them getting dirty.
    Thanks!

    I think its getting airbound from lo flow and lots of fresh water. A lot of people have been flushing this over and over to get it to heat.

    Im going to look good on this one!πŸ˜€
    But its not my smarts. Its you guys on this site. πŸ‘
  • ZmanZman Posts: 4,688Member
    If you set the DHW with priority, you can run the heat and DHW at different temps. Outdoor reset for the heat will help with efficiency.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icy78icy78 Posts: 243Member
    edited March 17
    > @Zman said:
    > If you set the DHW with priority, you can run the heat and DHW at different temps. Outdoor reset for the heat will help with efficiency.

    Yes. I think thats why the MV. Because they wanted DHW heating at 170, and wanted heating at the same time. But, the MV was set at 155 anyhow! Probably for the Fan coils Im guessing.
    I figure I'll install an ODR sensor and run the radiant and fan coils as cool as possible. I bet a lot of the winter they can get away with close to condensing. Particularly if i can get them to change to a vs pump.
    I think the NRF36 are too big anyhow. Altho at speed 1 ....maybe.

    Hmmmm, thinking about this some more.
    Say the mixing valve is there for the above reason. I did notice that the DHW ran alot. It must feed other buildings too. Maybe.
    So then a MV WOULD be needed, (to allow continuous heating as well) Except maybe this one is undersized. I wish i had the model but its 1" is all i know.

    Arent MV used successfully in these situations? And if so, is it an entirely different piping scheme?

    MV loop based off closely spaced tees?

    Since the DHW pump would also run, along with the boiler loop pump, and the emitter pump, would it then be necessary to have the DHW off CSTs also?
  • ZmanZman Posts: 4,688Member
    What model is the boiler and indirect?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icy78icy78 Posts: 243Member
    @Zman said:
    > What model is the boiler and indirect?
    The boiler is WM ultra 230
    The indirect i dont know. 100 gallon tank I think with 2.5 inch piping.

    I can set up the ultras no problem.
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,399Member
    What are the heat zones connected to? You said fan coils and radiant? What type or radiant?

    You could also be pulling air in through the spirovent since that mixing valve is very restrictive.

    If you determine that DHW and heating need to take place simultaneously (which may dictate the need to the MV) then a motorized valve or an injection loop may be better suited. Thermostatic mixing valves are best suited to small flows like big temp drops or a one room radiant heat job.
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • ZmanZman Posts: 4,688Member
    icy78 said:

    @Zman said:

    > What model is the boiler and indirect?

    The boiler is WM ultra 230

    The indirect i dont know. 100 gallon tank I think with 2.5 inch piping.



    I can set up the ultras no problem.

    The boiler is insanely oversized. The 1" piping will likely not be adaquate at full fire. I would put the DHW under full load and see how the boiler runs. If it goes to high fire, you will likely be OK using priority. If it will not, I would take a harder look at it all.
    If the original setup does not have flow checks on DHW and heating circs, it may be doing strange things that limit DHW output.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icy78icy78 Posts: 243Member
    > @Zman said:
    > @Zman said:
    >
    > > What model is the boiler and indirect?
    >
    > The boiler is WM ultra 230
    >
    > The indirect i dont know. 100 gallon tank I think with 2.5 inch piping.
    >
    >
    >
    > I can set up the ultras no problem.
    >
    > The boiler is insanely oversized. The 1" piping will likely not be adaquate at full fire. I would put the DHW under full load and see how the boiler runs. If it goes to high fire, you will likely be OK using priority. If it will not, I would take a harder look at it all.
    > If the original setup does not have flow checks on DHW and heating circs, it may be doing strange things that limit DHW output.

    The boiler piping is 1 1/4 as is the DHW.

    During DHW, pretty sure the highest % I saw was 60 on the ultra. I had it limited to 40% for a while because of air. I think it kept up.
    The brazed plate htex has 10 psi delta T hand-written on it.

    I "think" at 70 delta and 100 gallons water. The boiler could do it in 15 minutes plus htex loss. So ball park, say 20 minute recovery. Maybe a camp needs that.

    The injection idea from @Solid_Fuel_Man is great but too expensive.

    A lot of this work is at cost or free. Depending on how our owners feel about it.

    I'm hoping the removed piping idea you drew above will be accepted. (And workπŸ™‚)
  • ZmanZman Posts: 4,688Member
    So it is a DHW HX and storage tank? Do you have the size and plate count (model number)? What is the circ on the other side?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icy78icy78 Posts: 243Member
    edited March 17
    > @Zman said:
    > So it is a DHW HX and storage tank? Do you have the size and plate count (model number)? What is the circ on the other side?
    I dont know the tank loop circ.
    You'll notice its a listed refrigerant htex. Are they all that way? Headscratch.

    (I promised to take my kids on a hike so ill be off line a bit.)
  • ZmanZman Posts: 4,688Member
    That should be plenty HX and circ to make the boiler go 100%.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icy78icy78 Posts: 243Member
    > @Zman said:
    > That should be plenty HX and circ to make the boiler go 100%.

    Ok. So maybe because of the lack of checkvalves, there is circulation backwards thru the DHW loop when the DHW is not calling. Thus would result in heat pulled from the DHW tank and result in faster cycling of the DHW tstat. Further complicating the heating loop issue. However, running the DHW pump made no difference as to how badly the heating loop performed.
    Actually I'm wrong there, because the "heat stealing" would've been the other way....overheating the DHW tank. Which i didn't see happening.

    It seems to all point to the MV and how its piped.
    I have no idea how to check that and applucation of that MV but WM or Taco or someone will know. Its goofy anyhow because it drops temp to fan coils and radiant infloor at the same temp. No one knows whats in the floor or how its run.
    🀯
  • ZmanZman Posts: 4,688Member
    I was thinking that the DWH was reversing through the heat loops and losing energy thus taking longer to satisfy. It would be difficult for it to happen the other way around, assuming that the 2 circs on the HX are switched with the DWH call.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icy78icy78 Posts: 243Member
    > @Zman said:
    > I was thinking that the DWH was reversing through the heat loops and losing energy thus taking longer to satisfy. It would be difficult for it to happen the other way around, assuming that the 2 circs on the HX are switched with the DWH call.

    On the DHW call, the only change is that the DHW pumps on both sides of the htex run. Loop pump still runs and boiler pump runs. Plus the boiler setpoint changes from 160 to 170.

    So again as some of you have said. Get rid of the MV. However that would negate any benefit from ODR which presently isn't installed anyhow.

    Do you still think deleting the MV solves it, altho certainly not in the best way?
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,399Member
    If your heat emitters can handle all the same temps. Then eliminate the MV and put the DHW on it's own boiler temp.
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • ZmanZman Posts: 4,688Member
    Get rid of MV. Put checks on both DHW and heating circs.
    Set DHW priority and heating outdoor reset.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icy78icy78 Posts: 243Member
    > @Solid_Fuel_Man said:
    > If your heat emitters can handle all the same temps. Then eliminate the MV and put the DHW on it's own boiler temp.

    > @Zman said:
    > Get rid of MV. Put checks on both DHW and heating circs.
    > Set DHW priority and heating outdoor reset.

    Yes. I hope to get per to do that. Heat can still run during DHW, it'll just be at the DHW setpoint, which is fine. The rest of the time itll be under ODR control.
    Its all good I hopeπŸ‘ Haha, if the bosses are gone tomorrow I may just do it. If it works it'll all be good. If not....ah well. Easier to ask for forgiveness than permission.!
  • SuperTechSuperTech Posts: 935Member
    I would just do it. You will look like a hero for making this problem go away. It should work, definitely better than with the mixing valve in place.
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,399Member
    Thermostatic mixing valves have their place....that is not one of them!
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
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