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Need help with complex residential setup.

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I purchased a bi-level house in 2016 that has all infloor radiant heating. It utilized a heatmor manifold system (mounted in a hallway and in the garage) with 4 loops for upstairs, 4 for downstairs and 2 in the garage. The heating source was a water to water radiator with an outdoor wood burner and had a 40 gallon water heater as a backup. The house was built in 2001 and the heating system was never really service.

100% of the valve systems were clogged and none would open or close, so those were the first things to be ditched, the electronics for the pump control (1/25hp groundfos) didn't work correctly so basically I ran it on max temp test mode to kick the pump on.

The 1st winter was pretty awful, the wood burner was also neglected and didn't work right, so I tried using both the wood burner and the back up electric water heater, but the first month my electric bill was over $500 dollars, so the electric water heater wasn't used again.

Fast forward to Sept 2018, the backup electric water heater started to leak so it was time update the system.

I piped in a takagi propane unit in place of the electric water heater, so I could use that as my main heat source and keep the wood as a backup, so I piped in a ball valve to partially by pass the water to water radiator for the wood burner. I wanted to keep some heat going outside to help keep it from freezing.

However I've ran into some issues. I cannot get more than 1gpm flowing through the system (the heatmor manifolds don't have individual flow meters, so the takagi was the first time I could see flow). I tried burping the system, closing the garage loops off, different pressures, 1/6hp pump, and a few other things. For a while I was getting about 2.2gpm through the takagi and that seemed to be perfect.

Since I was going to be home all week I decided to burn wood and turn the propane off, but now I am only getting about .5-.7gpm and have gone through burping, changing valves, pumps, etc. for the entire system again and nothing seems to work.

I've been able to hook a hose up to the valve on the cold intake side of the takagi and it bumps the gpm up to about 3.0gpm but comes back down slowly. I've messed around with this for 15+ hours over the weekend so far and am out of ideas!

Few points:
-Water is seperate from wood burner, and wood burner has antifreeze in it as well.
-The system has 2 pumps, a 1/25 grundfos and a 1/125hp recir pump on the cold side, all valves/zones are open.
-There are no flow meters at the manifolds and I have 2 pressure gauges on the cold/hot side when I added the pex.
-I had the 'radiant heating guru' company come in and check everything out in 2015 and they were absolutely no help and only helped take about $200 bucks out of my pocket to say "well it looks good to me!"
-With flow averaging about 1.1gpm I ran through 8 gallons of propane per day from my last fill up. The takagi is the only propane appliance. House is about 1700sq including the heated garage and it was probably an average temp of 32F during those 35 days.

Here is a google drive link to pictures: https://photos.app.goo.gl/SRmWd6W7iaVSeZFF8

Please let me know if you have any suggestions, concerns, or ideas to help increase the flow of the system!

Thank you!

Comments

  • Jamie HallJamie Hall Posts: 10,469Member
    I believe the Takagi -- you don't mention the model -- is a tankless water heater, not a boiler? If so, it most likely has a very high internal head loss -- much higher than anything else in the system (the old electric had almost no head loss, by comparison). Also, if so, you may need to have a much higher head pump to get the flow you want and need.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • GroundUpGroundUp Posts: 516Member
    Oh boy.... I'm sorry but everything about this is bad news.

    -Your water temp is too high
    -Your new pex is too small
    -Your Takagi needs to be piped primary/secondary, and the primary loop needs a pump of the 26-99 variety
    -Your expansion tank is all but useless where it is
    -Your 10 plate exchanger is probably full of crap from being mounted like that

    For starters^^^^. I'm having some trouble grasping which lines go to where and how this system works at all. Where are you located? Someone needs to get over there and start over.
  • DICE033DICE033 Posts: 15Member
    Wow thanks for the quick responses!

    The model is T-H3-DV-P. I normally run it at 130F which gives me temps around 120F into the manifolds.

    The pex piping is 3/4, which replaced 3/4 copper where it made sense. I did it in pex so I could do a more permanent install next summer. I added in a picture of the original setup. All of the copper you see was from the original install; only the pex and takagi are what I've changed.

    I can map out the flow if that helps and if you have any links or examples of a setup that I could mimic that would be helpful!

    The plate exchanger works great right now but burning wood has been a huge pita, besides not being able to leave for long periods of time without family help, the burner is in the worse area of my property and getting wood to it is a huge burden.

    I do have a Stiebel Eltron 1/6 HP which I replaced the grundfos 1/25hp pump but that netted marginally better flow and a tornado siren sound throughout the house. I put the 1/25hp pump back right before taking those pictures.
  • GroundUpGroundUp Posts: 516Member
    3/4" pex is considerably smaller ID than 3/4" copper and only good for about 4 GPM in a system like this which is pretty light for 10 loops. A flow map would be of considerable help for me if you could, there are a few items hidden by other piping that I/m unable to see from your photos, like above the plate bypass with the blue pex- where does it go? Which reminds me, this looks a lot like Menards tubing which is non barrier and should not be used in closed loop radiant like this. The 1/25 and 1/6 HP designations you're giving the pumps mean nothing more than the motor size, we will need model numbers. The Grundfos appears to be a 15-58FC from here. The Stiebel I can only assume is a 26-110FC and would be a great candidate for the primary loop to overcome the high head of the Takagi. Where the tornado siren sound comes from I am not sure though. Are there zone valves on this system anywhere or does that 15-58 just serve all 10 loops from a single thermostat? Also your location would be handy

  • VoyagerVoyager Posts: 211Member
    It is a little hard to visualize your complete system from the pictures. Going from 3/4” copper to 3/4” pex cost you about 1/3 of your flow potential. See the link below. You would have had to upsize to 1” pex to maintain the flow you had with the copper. Or use pex-al-pex which is close to copper in ID.

    Also, you have a lot of elbows which cause a lot of head loss and the heat exchanger may also be a fairly high loss device. You may well need to step back and rethink your near ”boiler” piping and streamline it to remove some of the elbows and, if you want to stay with pex, upsize to 1” pex from the water heater to the distribution manifolds.

    http://s3.supplyhouse.com/manuals/1322593642270/68976_PROD_FILE.pdf
  • DICE033DICE033 Posts: 15Member
    Added 2 pictures to show the flows. I think I've stared at it long enough that its 'simple' to me.

    Streamlining the system is my plan for next summer, along with updating the manifolds. I can remove most of the copper piping and bends where the original hot water tank was. I just need some suggestions for increasing flow with whats available now.

    Right now its all controlled through an EcoBee thermostat which in turn controls the 1 pump.

    The PEX was suggested to me by a buddy who does plumbing for rental properties and is from Menards. It does say "Radiant Heating/No Oxygen Barrier" on it.

    The part numbers for the pumps are 15-58FC and 26-110FC. The Circulating pump is a SMT-303 and the copper is plumbed down to 1/2 inch copper for the pump.

    Would changing that Laing SMT-303 pump out for something more powerful overcome the head created from the Takagi?

    While I'd like to have more flow overall, I did find 2gpm warmed the house up quickly. Even now at .7gpm I can keep everything but the garage around 68-70F.

    I am also located in Mid-Michigan.

  • GroundUpGroundUp Posts: 516Member
    A closed system like this needs to be oxygen barrier, or o2 will permeate the walls and cause oxidation in the ferrous components of the system such as pump and expansion tank.

    The Laing is doing absolutely nothing now and a larger circ in that position would solve very little either. With a flow rate like .7 GPM, even at a 50 degree delta T, you're only moving 17,500 BTU which may suffice for 30 degree temps but will soon be inadequate once it gets cold.

    I'm too dumb to be able to post pictures, but if you'll Google "primary secondary piping" and do some reading will get you some info. Essentially what you'll want to do is eliminate all the garbage over to where the old tank was and build a short "primary" loop between the hot and cold ports of the Takagi with the 26-110 in it pumping into the cold side that circulates the water heater and plate exchanger only, with the plate being first in line so when the OWB is burning that plate will preheat the incoming "cold" water to the Takagi. 2 tees in that loop right next to each other (called closely spaced tees) would hydraulically separate the 2 loops and these tees would serve the secondary loop, located between the plate and "hot" port of the Takagi. The tee closer to the hot side of the Takagi would get piped to the inlet of the existing 15-58 and feed hot water to the radiant loops while the return from the radiant would get dumped back into the second tee to be returned to the plate and Takagi for reheating. The expansion tank will need to be relocated to the inlet side of the 26-110 in order to function, just cut in a tee with a female adapter if you're content with having air in your system or better would be to add an air eliminator (Spirovent type) in the same place and screw the XT into it. This should allow you 3-4 GPM through the Takagi and 4-5 through the radiant once they're decoupled. I've been up for 30 hours so I'm having a bit of trouble concentrating here but hopefully that makes sense and you can fix it up good enough to work.
  • VoyagerVoyager Posts: 211Member
    You definitely need oxygen barrier pex if you want the iron components in hour system to last (pump impellers, etc.).

    The only two ways to increase flow rate are to apply more pressure (higher head circulator) or to reduce flow resistance (larger pipe, fewer elbows, etc.).

    Here are some common pump curves so once you know the head loss in your heat exchanger, water heater and piping (there are rules for equivalent length of each fitting, etc.), you can draw a line on the pump curve chart and then pick a circulator that will provide the flow you desire at the head that your system has.

    https://www.builditsolar.com/References/Pumps/PumpCurves.htm
  • DICE033DICE033 Posts: 15Member
    Since I had an extra day off, I decided to mess with it again.

    I removed the Laing SMT-303 and replaced it with the 15-58FC so that would be on the cold water side of the Takagi and the 26-110FC is on the hot side.


    When I first put water back into the system, I was getting about 2.6-2.8gpm which was perfect. However, I decided to burp the system again and now its hovering around 1.5gpm.

    I burp the basement 4 loops first, then the 4 upstairs loops and then the 2 garage loops. I feel like everytime I get to the garage loops I start to lose overall flow in the system. The garage manifolds are in bad shape and I rarely get any air coming out of the air seperator for them and marginal flow from the hose on the cold manifold, certainly not full pressure like the other manifolds. The plastic fitting also leaks when I try and burp these loops.

    The garage manifold is the highest point in the system, but the loops themselves are lower than the upstairs. The upstairs loops are the highest point but the manifolds are about ground level, but those seem to be where I get the most air escaping.

    Does anyone have any suggestions for burping the system or youtube suggestions?
  • VoyagerVoyager Posts: 211Member
    DICE033 said:

    Since I had an extra day off, I decided to mess with it again.

    I removed the Laing SMT-303 and replaced it with the 15-58FC so that would be on the cold water side of the Takagi and the 26-110FC is on the hot side.


    When I first put water back into the system, I was getting about 2.6-2.8gpm which was perfect. However, I decided to burp the system again and now its hovering around 1.5gpm.

    I burp the basement 4 loops first, then the 4 upstairs loops and then the 2 garage loops. I feel like everytime I get to the garage loops I start to lose overall flow in the system. The garage manifolds are in bad shape and I rarely get any air coming out of the air seperator for them and marginal flow from the hose on the cold manifold, certainly not full pressure like the other manifolds. The plastic fitting also leaks when I try and burp these loops.

    The garage manifold is the highest point in the system, but the loops themselves are lower than the upstairs. The upstairs loops are the highest point but the manifolds are about ground level, but those seem to be where I get the most air escaping.

    Does anyone have any suggestions for burping the system or youtube suggestions?

    Are you purging using the water feeder? My system purged well that way, but often using a hose directly from the water supply will give you more flow. Are there any purge stations on your system?
  • GroundUpGroundUp Posts: 516Member
    Cut it apart and pipe it primary secondary
  • DICE033DICE033 Posts: 15Member
    Voyager said:

    DICE033 said:

    Since I had an extra day off, I decided to mess with it again.

    I removed the Laing SMT-303 and replaced it with the 15-58FC so that would be on the cold water side of the Takagi and the 26-110FC is on the hot side.


    When I first put water back into the system, I was getting about 2.6-2.8gpm which was perfect. However, I decided to burp the system again and now its hovering around 1.5gpm.

    I burp the basement 4 loops first, then the 4 upstairs loops and then the 2 garage loops. I feel like everytime I get to the garage loops I start to lose overall flow in the system. The garage manifolds are in bad shape and I rarely get any air coming out of the air seperator for them and marginal flow from the hose on the cold manifold, certainly not full pressure like the other manifolds. The plastic fitting also leaks when I try and burp these loops.

    The garage manifold is the highest point in the system, but the loops themselves are lower than the upstairs. The upstairs loops are the highest point but the manifolds are about ground level, but those seem to be where I get the most air escaping.

    Does anyone have any suggestions for burping the system or youtube suggestions?

    Are you purging using the water feeder? My system purged well that way, but often using a hose directly from the water supply will give you more flow. Are there any purge stations on your system?
    I use a hose on the cold side, turn off all ball-valves on every manifold, manually turn off all the cold valves per loop and manually open one at a time. I open the drain on the manifold and let water flow out of that.

    It seemed great until after I did the garage. 2.6gpm and now its sitting around 1.5gpm.

    Groundup, I plan on redoing the system in a more permanent style over the summer.
  • DICE033DICE033 Posts: 15Member
    edited January 3
    GroundUp said:

    Cut it apart and pipe it primary secondary




    Is a good picture of primary/secondary plumbing that would work with what I have?
  • DICE033DICE033 Posts: 15Member
    Ok so if you look at my pictures in the google drive. I *believe* I essentially have a closely spaced tee (I'll add more pictures after work). But I ended up adding a valve there because when I originally installed the Takagi and only had 1 pump, that pump was pulling the return water from the manifolds back through the loop and not giving me any flow from the heat source. If I needed to run to menards and get a real closely spaced tee, I am fine with that.

    The only thing I would need to do is:
    -Add the air seperator and the expansion tank to a better location before the primary loop pump

    -And set the heat plate for the OWB on the cold side of the Takagi instead of the hot side. (Takagi won't overheat with preheated water?)
  • hot_rodhot_rod Posts: 11,465Member
    What size is that plate heat exchanger? it looks small from the pi , it could also be the cause of your high pressure drop, and lack of btu..
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • ZmanZman Posts: 4,896Member
    Does the OWB need to be heated to prevent freeze up when not in use? If so you should think long and hard about keeping it, especially since you don't sound enthusiastic about running it. It is not cheap to keep that much water and mass warm all winter in an outdoor environment.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • VoyagerVoyager Posts: 211Member
    edited January 3
    I looked at your pictures again, but in all honesty the piping is so convoluted I can’t follow it from the pictures. It might help if you show a picture of just what you consider the primary loop and clearly show the circulator for that loop and circle the closely spaced tees. The rule of thumb is that the center to center spacing of the pipes coming out of the tees should not exceed 4 pipe diameters. I believe most use the nominal pipe size so 3/4” pipe would limit spacing of the tees to 3” on center. However, if you look at the actual ID of the pipes, 3/4” pex is only 0.681” so 4 times that is only 2.72” so I would definitely not want to have the spacing exceed 3” and less is better since the PEX ID is not the same or larger than the nominal size as with copper.

    My Triangle Tube boiler is a low head boiler as I believe the water path through the heat exchanger is simply 1” copper pipe. Even so, I used 1” copper as my primary loop and I upsized to 1-1/4” in my home-made closely spaced tee to ensure low flow velocity and thus low pressure differential between the two legs of the primary loop connections.
  • DICE033DICE033 Posts: 15Member
    Voyager said:

    I looked at your pictures again, but in all honesty the piping is so convoluted I can’t follow it from the pictures. It might help if you show a picture of just what you consider the primary loop and clearly show the circulator for that loop and circle the closely spaced tees. The rule of thumb is that the center to center spacing of the pipes coming out of the tees should not exceed 4 pipe diameters. I believe most use the nominal pipe size so 3/4” pipe would limit spacing of the tees to 3” on center. However, if you look at the actual ID of the pipes, 3/4” pex is only 0.681” so 4 times that is only 2.72” so I would definitely not want to have the spacing exceed 3” and less is better since the PEX ID is not the same or larger than the nominal size as with copper.

    I'm fairly certain the spacing is more than that. I don't have any pictures of the setup with the 2nd pump in it up there yet either. I can pipe in a Tee from Menards rather quickly so I might try that.
  • DICE033DICE033 Posts: 15Member
    I uploaded a picture with a green line that shows the secondary piping. That is easier to see in the picture. The 2nd pump I installed is where the gauge is on the blue pex in that same picture as well.
  • GroundUpGroundUp Posts: 516Member
    You've got what appears to be a 10 plate exchanger and the head loss from it at the flow rate you're seeing is not even worth the ink to write down. The "close tee" things from Menards are not worth buying, when you can buy a pair of tees for 5% of that cost and have a superior hydraulic separation without the pressure drop from the valve in between. What you have now is not, and can not be made to work as P/S without completely tearing it apart and starting over as I explained in my earlier post. The drawing you posted is pretty accurate, except the plate exchanger is piped backwards on the OWB side. You'll want the OWB water flowing in the opposite direction of the Takagi water across the plate.
  • DICE033DICE033 Posts: 15Member
    I'm fairly certain my primary plumbing is setup similar to the picture I posted, with these exceptions:

    -Expansion tank isn't where it should be (but is on intake side of pump)
    -Close Tees aren't close enough
    -Plate Exchanger is on the on hot outlet side

    While I understand that the entire system has a lot of excessive piping, I want to focus on what would give me the biggest bang for the rest of the winter and I assume that would be the close tees as that's where the witchcraft of the hydraulic separation happens?


    Another question. Since now I am running 2 pumps, I am using a Taco SR503-4, is there anyway to have that control both pumps?
  • DICE033DICE033 Posts: 15Member
    Ok replacing this:


    with this:



    That should greatly improve the witchcraft of creating the Primary and Secondary flows? I am also going to be able to eliminate a few of the bends there for the heat as well.
  • VoyagerVoyager Posts: 211Member
    edited January 5
    DICE033 said:

    I'm fairly certain my primary plumbing is setup similar to the picture I posted, with these exceptions:

    -Expansion tank isn't where it should be (but is on intake side of pump)
    -Close Tees aren't close enough
    -Plate Exchanger is on the on hot outlet side

    While I understand that the entire system has a lot of excessive piping, I want to focus on what would give me the biggest bang for the rest of the winter and I assume that would be the close tees as that's where the witchcraft of the hydraulic separation happens?


    Another question. Since now I am running 2 pumps, I am using a Taco SR503-4, is there anyway to have that control both pumps?

    The hydraulic separation may or may not help your problem. If the head loss is due to all of the piping in the secondary (distribution) loop, then isolating the water heater from that loop will increase flow through the water heater, but not through the secondary loop.

    It would be interesting if you measured the length of your piping and counted up the fittings to estimate head loss in your loops.
  • DICE033DICE033 Posts: 15Member
    I don't think I could measure the lengths but the entire house is only about 1700sq. with a 24x24 garage that has in floor heating too.

    The heat seemed to work good before when I was straight on wood so I assume the loops *should* be good?
  • GroundUpGroundUp Posts: 516Member
    The secondary side will be fine with the 15-58, assuming worst case with your loops being 300ft long and 1/2", your head loss is less than 5 ft through the floor. Your close tees can be up to 7" apart, but the closer the better. The 15-58 can stay in the secondary loop and the primary needs to be fed with the 26-110 to decouple the Takagi from the rest of the system. If you're certain you could separate them with the mess that's currently there, please do. As long as you get them hydraulically decoupled and eliminate as much head as possible in the primary, you should be alright for now
  • GroundUpGroundUp Posts: 516Member
    As for the primary pump, how are you using a 503-4 with a single zone and thermostat? A 501 would serve the same purpose. Are you firing the Takagi using the isolated end switch? Otherwise you would be able to (I think) utilize the end switch to transfer power to the primary circ under any call for heat. I don't have an SR in front of me, but I believe the ZR becomes hot with any call for heat as well
  • DICE033DICE033 Posts: 15Member
    edited January 7
    I redid the piping over the weekend, eliminated some of the piping as well, but forgot to switch the OWB plate exchanger over to the intake on the takagi. The Takagi is set to 130F and I am getting about a max of 92F at the manifolds. Before the hydraulic seperation and the Takagi set to 130F I would get about 115F.

    I also I noticed once the 503 isn't calling for heat the Takagi turns off once the intake temp hits about 115F. It cools off to about 105F and turns back on. This cycle takes about 3-5 minutes, so I def need to figure out how to turn both pumps on/off with heat call. This is with the primary pump running all the time.

    So you are saying to use the far left ZC and ZR to wire to the Primary Circ pump?


  • GroundUpGroundUp Posts: 516Member
    So the Takagi runs wide open and cannot produce more than 92 degree water? Or it heats up to 115 on the inlet and kicks out because the outlet is 130? Your supply temp at the manifold should read very close to what is coming out of the Takagi if you are piped sufficiently. Almost sounds like the secondary is causing bi-directional flow between the close tees and recirculating the return water from the radiant- can you slow down the 15-58? As for the 503, one of those terminals either ZC or ZR (or both, given the jumper) becomes hot with any heat call and would be able to power the primary circ from what I understand. I'm electrically handicapped but I know it's been done
  • DICE033DICE033 Posts: 15Member
    Takagi is definitely putting out 130F but even before I put the close tees, I was still getting a temp drop (from the plate) but now its dropped down to 92F or so. I am running the 15-58 on high and the 26-110FC on low. I am also only getting 1.6gpm through the takagi but I can tell I am getting more flow through the manifolds, but have no way to tell how much since the only flow meter I have on the system is the takagi.
  • VoyagerVoyager Posts: 211Member
    If you have a lot more flow in the secondary loop, that will lower the temp in the exchanger as you are moving more heat through it. Remember, heat and temperature aren’t the same thing. If you have a lot more flow, even at a lower temp, you are likely moving more BTUs.
  • GroundUpGroundUp Posts: 516Member
    Speed up the 26-110 to 3 and see what the primary flow does. Is the pump at the Heatmor running or where is that 38 degrees going? This is why it needs to be on the inlet side of the Takagi piped in the primary loop
  • DICE033DICE033 Posts: 15Member
    GroundUp said:

    Speed up the 26-110 to 3 and see what the primary flow does. Is the pump at the Heatmor running or where is that 38 degrees going? This is why it needs to be on the inlet side of the Takagi piped in the primary loop

    So I finally had a chance to put the OWB plate exhanger on the cold side going into the Takagi.

    Now I have it set to about 115F but am still only getting about 92F at the manifolds. You can feel where the return water is mixing with the hotside at the closely spaced tee that runs to the pump on the secondary side.

    I'll speed up the 26-110 and see what happens. It'll be on speed 3 and the secondary pump will be on 3 as well.
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