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Optimize pumps for radiant floors

Chris_51
Chris_51 Member Posts: 46
I put in my first radiant floor in my kitchen 22 years ago. I followed with some radiant at my office, then a floor in my bathroom about 5 years ago.

My house is old. A modified single pipe system. It started as gravity with no pump. So the pipes are huge it holds 1,000 gallons. Seriously.

For the kitchen and bathroom, we used the feed/return from a radiator we tool out. It works fine.

Now that I have an Electric Car, I started looking at where all my electricity was going. I checked everything.

My notes say the kitchen pump uses 72w. The bathroom 36w. Then two small pumps for some add-on baseboard radiators that are 38w each. Basically, $25/month in electricity.

I calibrated the kitchen with a mixing valve to get the right temp with 24/7 pumping.

I’m thinking I could probably cycles the kitchen an bathroom to run 5 minutes every 20, then rely on the mass to keep it going.

Does anyone know of a timer that works that way? I have one weird one that cycles, but it has an IR, so its only at night. Maybe there is something better?




Comments

  • hot_rod
    hot_rod Member Posts: 17,531
    Can you combine the 3 zones and use one pump? An ECM high efficiency circulator to handle that should run somewhere between 27 and 44 W
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    hot_rod said:

    Can you combine the 3 zones and use one pump? An ECM high efficiency circulator to handle that should run somewhere between 27 and 44 W

    They are on different floors of the house, so I don't think so.

  • Chris_51
    Chris_51 Member Posts: 46
    I guess the timer in the picture works in a 24 hour mode. I'll start with that. The granularity is pretty good. I think I'll start with 1 minute every 5. Then adjust from there. I might tweak the mixer to be a bit hotter to compensate.
  • hot_rod
    hot_rod Member Posts: 17,531
    If the system is sized accurately, on design days it should run continuously. You may be able to pulse heat for a portion of the heating season. The toughest operating condition for electric motors is stop and start, so expect a shorter life span.

    Do you have ECM type pumps? They consume 50- 80% less power according to manufacturers, 50% is certainly realistic, from my experience.

    Is that rubber tube with hose clamps??

    In some areas there are utility rebates to upgrade circulators to ECM type, check here.

    www.dsireusa.org
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    Just a Taco. I never looked inside the box next to it. I don' think this transformer is doing anything if it runs 24/7, right? The plumber did that part.

    I found the transformer for the boilers is using a huge amount of power too. My cousin did the boilers. I think he tried to save buying something new. I paid dearly in electricity for that one.




    hot_rod said:



    Do you have ECM type pumps? They consume 50- 80% less power according to manufacturers, 50% is certainly realistic, from my experience.

    Is that rubber tube with hose clamps??

  • hot_rod
    hot_rod Member Posts: 17,531
    Really shouldn't need that transformer if there is one in the boiler. Do the pumps wire to a relay box? Or do the wires from that transformer go to relays for the 3 circulators? Any other components in that junction box?

    There is one position that the circulator should not be mounted in. You got it :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • Chris_51
    Chris_51 Member Posts: 46
    On the transformer, I sort of remember it now. They put a thermostat in the kitchen, in the space behind the trash. I think that was a test. But it was maxed out, so was basically doing nothing all these years.

    So the transformer and relay were using 17w. The pump alone uses 80w I'm going to try the short cycle timer to see if it works running 1/3 of the time. Those two teaks will save $10 a month in electricity. Hopefully the pump won't fail.

    On the position, I'm not sure how to read the doc you posted. So I should twist it? Here is a better picture.

    Those were hose clamps on the tubes. Is that bad?


    hot_rod said:

    Really shouldn't need that transformer if there is one in the boiler. Do the pumps wire to a relay box? Or do the wires from that transformer go to relays for the 3 circulators? Any other components in that junction box?

    There is one position that the circulator should not be mounted in. You got it :)

  • hot_rod
    hot_rod Member Posts: 17,531
    That is a better pic of the circulator, it is okay in that position, it's better to have the terminal box on top, but not a deal breaker like you have it.

    Not to add to your concerns, but a circ like that is only about 20-25% efficient when it is running. When it is time to replace it, go with the ECM style circulator. Most ECM have variable or multiple speeds, you could cut that 70W by 1/3 possibly.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    edited September 25
    Thanks for all the info. Very helpful.

    The weather is in the middle, so I did a few test burns on the boilers without overheating. I'm running a staged two boiler system. There are a lot of pumps.

    I think the red one is grossly oversized. When we build this system, the guy at the parts store said to do a small loop for the two boilers. Then the big loop for the house pulls from that. Its a single pipe system, so only one loop. If you can see it, that big pump to the lower right is the one I think I should swap with an ECM. It's using 200w. It runs when the boiler logic is on, so 24/7 during heating season.

    I'm not sure it really needs to run 24/7. But I'm not sure how to design around either.

    DO you agree with a smaller ECM there?




    hot_rod said:

    That is a better pic of the circulator, it is okay in that position, it's better to have the terminal box on top, but not a deal breaker like you have it.

    Not to add to your concerns, but a circ like that is only about 20-25% efficient when it is running. When it is time to replace it, go with the ECM style circulator. Most ECM have variable or multiple speeds, you could cut that 70W by 1/3 possibly.

  • hot_rod
    hot_rod Member Posts: 17,531
    Yikes! Hard to tell exactly what is going on there? I can't tell what is what, some partially closed ball valves for some reason? Some sort of primary secondary perhaps?
    Vent piping look suspicious :wink:

    Same installation guideline for that Grundfos circulator regarding the mounting position. The directions in the box usually show the proper way to mount them.

    To select a circulator you need to know 3 things
    type of fluid
    GPM required
    Head of the connected piping

    This journal takes you through the steps to select a circulator pump.

    https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_16_na_0.pdf
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    Thanks. Here is a diagram. I took the double boiler model from Dan's book and marked it up.

    The loop is pretty small. So a 200w pump has to be overkill - the one labeled primary. Do you agree?

    I'm not sure all the terms to make an actual calculation.

    I saw Taco has an ECM pump with a non-ecm model it replaces. The one I saw was $220. I could do that price for the floor. A direct swap would be nice.


    hot_rod said:

    Yikes! Hard to tell exactly what is going on there? I can't tell what is what, some partially closed ball valves for some reason? Some sort of primary secondary perhaps?
    Vent piping look suspicious :wink:

    Same installation guideline for that Grundfos circulator regarding the mounting position. The directions in the box usually show the proper way to mount them.

    To select a circulator you need to know 3 things
    type of fluid
    GPM required
    Head of the connected piping

    This journal takes you through the steps to select a circulator pump.

    https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_16_na_0.pdf

  • hot_rod
    hot_rod Member Posts: 17,531
    You have what is known as a series primary loop. That primary loop circulator needs to move the gpm output of the two boilers. What size are those boilers?

    It has always been an awkward circ to size, that primary loop one. It may be a high gpm requirement, but only a few feet of head.

    I would not add a valve between the closely spaced tees as the drawing indicates? A purge valve on the "return house loop" is what you need for a good purge point.


    I suspect the primary circ is oversized. Once we know the BTU of the boilers we will know.

    I'm still wondering about these partially closed ball valves? Should not need anything like that in the piping that you are showing?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    I think 266k each. They are too big though. I wanted a staged system. I almost never need both. The boilers each have their own pumps. Those only work when firing. But the primary pump is 24/7. At 200w, that is hurting me on efficiency.

    The partially closed valves let a bit of hot water cycle back. To avoid some sort of shock. Its in Dan's book somewhere.

    On the valve to the house loop, I can close it a bit to push some water out to the house from the primary. I could have the whole house act as a primary loop. I tried it, but it didn't work well.

    The system usually runs without the house circulator pump. If it needs a kick, the thermostat in the main room upstairs gives that pump a kick.

    The logic needs the water temp, the outside air temp, and a reading from the room. Ideally it would just adjust the temp of the water. But with the old gravity as a starting point, the 1,000 gallons of water tends to overheat.

  • Chris_51
    Chris_51 Member Posts: 46
    Chris_51 said:


    I could quote the part I wanted to for some reason, so I wrote a separate comment.

  • hot_rod
    hot_rod Member Posts: 17,531
    Kind of coming at this backwards. The correct way would be
    To first determine the heat load of the building
    Then select the boiler
    Then the pumps and pipes are sized to the load and boiler flow requirements.

    If you have the 256, the output is 223,000 BTU/hr. So a 22 gallon per minute flow would be needed to move all the output of the boiler.
    Under those conditions each boiler would need a pump able to move 22 gpm @ 20 °∆

    Then if both are running the primary loop needs to be able to move 44 gpm, output from both.

    It gets even more complicated with a gravity conversion as they want low flow to mimic the gravity conditions, so I'm told. Even though gravity flow can be quite fast also., but you may still need to move 44 gpm around your primary loop.
    So determining all pump sizes depends on how much you need to move.

    I suspect if both boilers never need to fire together to cover the load, the load must be at or under 223,000 btu/ hr. the output of one boiler. True or false?

    If so the all the pumps could size to that load, boiler pumps, primary pump, and system pump.

    So trial and error is the other pump sizing method. If what you have works, replace them with ECM of the same capacity. You get the efficiency boost regardless.

    You certainly do not want to buy a 40 gpm ECM $$ circ if a 22 gallon is adequate.

    Here is your 43-75 single speed pump performance curve. Need to know exactly how the primary loop is built to get the head number. I'd guess that primary pump could be moving around 30 gpm.

    Also attached is a Grundfod Magna. A very adjustable circulator as you can see by the pump curves. Is it worth 900 bucks to 1/2 your power consumption?

    Your utility may have rebates for high efficient pump upgrades, look here www,dsireusa.org

    Once again, if the building only needs 223,000 btu/hr, then that loop circ would not need to move more than that.

    Is the second boiler just for a back up perhaps.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    I'm 100% confident this is all backwards.

    When I bought the house, it had a boiler from the 60s. It was 6x6x6. It grossly overshot. When the old owner closed out his account, the gas company said it messed up billing 200/mo and sent him a bill for $3,500. Oops.

    So I did the upgrade in 2005ish. I head heating help. The double boiler made sense. The guy at the local supply house offered a design service. So we did that. This was his plan. He likely too the old boiler stats, split by half, then sized up. I would have sized down in hindsight.

    On a cold startup, they both fire. Occasionally , they both fire. Most of the time, only one fires. Two years ago, the inside control boards on the second one failed. Just loose wires. We didn't notice that the first one failed too, so when it was col, we noticed. So we probably ran on one for a while.

    On the size, I previously looked up the model online. But he sticker is lower. More like 153 OP. So 65% of your calculations. So that puts me at 14.5 each. 29 total.

    I'm thinking a 20 GPM will be fine. If it is under, what is the downside? I think I'll just hit the high limit faster, right? The they shut off and let the heat bleed into the system. No big deal to me.

    I did order an ECM for the floor. If that really cut the power consumption as advertised, I'll tackle this one. I'll have that one on Friday.

    On another note, I asked everyone if different transformers have better efficiency. The one for the floor was draining 17w. The old one on the boiler is using 20w. But this taco at my office only uses 3w. Wow. So the 17w transformer on the floor, that never was actually used, cost be $350 in electricity in today's rates. I'll at least get the taco 24AC box for the boilers.

    Please comment on the primary pump at 20 GPM. Is there a preferred model? I'm running 2 inch pipe. The flanges are huge. Your help is greatly appreciated.





    hot_rod said:

    Kind of coming at this backwards. The correct way would be
    To first determine the heat load of the building
    Then select the boiler
    Then the pumps and pipes are sized to the load and boiler flow requirements.

    If you have the 256, the output is 223,000 BTU/hr. So a 22 gallon per minute flow would be needed to move all the output of the boiler.
    Under those conditions each boiler would need a pump able to move 22 gpm @ 20 °∆

    Then if both are running the primary loop needs to be able to move 44 gpm, output from both.

    It gets even more complicated with a gravity conversion as they want low flow to mimic the gravity conditions, so I'm told. Even though gravity flow can be quite fast also., but you may still need to move 44 gpm around your primary loop.
    So determining all pump sizes depends on how much you need to move.

    I suspect if both boilers never need to fire together to cover the load, the load must be at or under 223,000 btu/ hr. the output of one boiler. True or false?

    If so the all the pumps could size to that load, boiler pumps, primary pump, and system pump.

    So trial and error is the other pump sizing method. If what you have works, replace them with ECM of the same capacity. You get the efficiency boost regardless.

    You certainly do not want to buy a 40 gpm ECM $$ circ if a 22 gallon is adequate.

    Here is your 43-75 single speed pump performance curve. Need to know exactly how the primary loop is built to get the head number. I'd guess that primary pump could be moving around 30 gpm.

    Also attached is a Grundfod Magna. A very adjustable circulator as you can see by the pump curves. Is it worth 900 bucks to 1/2 your power consumption?

    Your utility may have rebates for high efficient pump upgrades, look here www,dsireusa.org

    Once again, if the building only needs 223,000 btu/hr, then that loop circ would not need to move more than that.

    Is the second boiler just for a back up perhaps.

  • hot_rod
    hot_rod Member Posts: 17,531
    Sounds much better. The circs on the boiler would need to move 15 gpm to get full output. Cast boilers are very forgiving to flow so 12, even 10 gpm would not harm the boiler. 

    Are the boiler circs multiple speed models? If so try speed 1 or 2 and see if you get the output you need on cold days. The lower the speed, the less power consumption

    Now you have two other circs, the 43-75 primary one, then a distribution one for the building

    The primary one would need to move 25- 30 gpm to get full output from both boilers moving around the loop, that may be the best upgrade at 200w currently

    What model is the building distribution circ? Is the building zoned either with zone or manual valves now? If so a delta P function on an ECM would reduce power consumption even more 
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Great reading. What is the square footage of your house?  Any plans to get some solar panels on the roof?
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
  • Chris_51
    Chris_51 Member Posts: 46
    Here is a pic of one of the boiler circulators. So 15-58 I'm guessing means 15 GPM, right? So those are in spec. They only run when the boiller is heating, so not as big of a concern.

    The primary is 24/7, so that is $27 a month to run the EV 750 miles. So 21 gallons of gas in a 35MPG car.

    If I go 20 GPM, a bit undersized, then what happens when both boilers fire? I think they might just limit out, right?

    The building distribution circulator is the same model 43-75. That is controller by a thermostat, so not as important to swap IMO.

    No zones. Just a huge circuit. They started the house in 1928. When the market crashed, they stopped, then picked it up in 1932 ish. They redesigned and stretched it out. The two rooms above the garage have a sub-loop, but no control. In the pics, the pipe looks about 3 inches at the back of the house. The split feeds the garage. So that is semi warm. No controls anywhere. Amazing it works so well. It's balanced, no hot spots.




    hot_rod said:

    Sounds much better. The circs on the boiler would need to move 15 gpm to get full output. Cast boilers are very forgiving to flow so 12, even 10 gpm would not harm the boiler. 


    Are the boiler circs multiple speed models? If so try speed 1 or 2 and see if you get the output you need on cold days. The lower the speed, the less power consumption

    Now you have two other circs, the 43-75 primary one, then a distribution one for the building

    The primary one would need to move 25- 30 gpm to get full output from both boilers moving around the loop, that may be the best upgrade at 200w currently

    What model is the building distribution circ? Is the building zoned either with zone or manual valves now? If so a delta P function on an ECM would reduce power consumption even more 
  • Chris_51
    Chris_51 Member Posts: 46
    I'm glad you are enjoying I'm learning a lot from Hotrod.

    The house is 5800. Plus a partially finished basement. I have a guitar shop as a side business in the basement too. I did a ton of electrical stuff over the years.

    I have thought a lot about solar. That looks expensive. I EV charger I jut put in (the pic with the giant jackhammer was running the wires) has a mode that only charges when there is excess solar. I think that makes it a lot easier so you can avoid an expensive storage batter. So a hybrid setup. Just taking the load off the grid.

    I did look at a geothermal supplement a few years ago. I should have shopped it more. The Geo company wanted me to pull the boilers. No way. Their reason was dumb - if something went wrong would you call them, or the boiler company. So I passed. I figured an underpowered Geo, with the boilers there on the cold days. The Geo would just feed the same giant loop. The boilers would just see warmer water returning longer.

    Great reading. What is the square footage of your house?  Any plans to get some solar panels on the roof?

  • hot_rod
    hot_rod Member Posts: 17,531
    Really no reason the primary pump needs to run 24/7. It only needs to run when the distribution circ is running to connect the heated water with the load.

    How is the system controlled. A or multiple thermostats call on the distribution circ, in turn the boilers?

    Most cast boilers could run without any flow. It’s just a large cast iron kettle. It would run up to temperature and shut off at setpoint. If there is a minimum flow required the IO manual would indicate that. 
    Regardless, a heat call could fire all the necessary circulators at once, a cold start option. Or idle the boilers into the loop, that is why you have primary secondary piping to hydraulically separate the various systems

    Low mass boilers need flow due to small water content, thin metal heat exchangers

    Did the former gravity system boiler have a circulator? 
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    hot_rod said:

    Really no reason the primary pump needs to run 24/7. It only needs to run when the distribution circ is running to connect the heated water with the load.

    How is the system controlled. A or multiple thermostats call on the distribution circ, in turn the boilers? 

    This is how this system is a bit strange. It just monitors the temp of the water and adds heat as needed. No real call for heat. Here is the sensor diagram:



    Here is the two boiler diagram:



    Here is one I found in the papers. My cousin was showing off in Visio doing perspectives.



    I talked to a Buderus tech once. He said my setup was the perfect application for this mode. Just adjust the water temp. But, back to the 1,000 gallons of water. We can cut adding heat all night, and the air temp only drops a bit.

    There is a room sensor too that isn't shown. That does let us control the target temp.
    hot_rod said:




    Most cast boilers could run without any flow. It’s just a large cast iron kettle. It would run up to temperature and shut off at setpoint. If there is a minimum flow required the IO manual would indicate that. 

    Regardless, a heat call could fire all the necessary circulators at once, a cold start option. Or idle the boilers into the loop, that is why you have primary secondary piping to hydraulically separate the various systems

    Low mass boilers need flow due to small water content, thin metal heat exchangers

    Did the former gravity system boiler have a circulator? 

    You can see the extra circ in this pic.



    That was not part of the original house system. Someone added a circ there connected to a thermostat. The gravity will move the water without this one, but it is slow. Once it gets going though, it is hard to stop. So that circ just speeds up heating. We did replace that one sometime before 2005.

    So I do think I need the primary pump going 24/7 so the logic can see the house water temp. Do you agree?

    That wasn't how the house was built, but the semi-modern Buderus log needs it. In this pic you can see the primary is connected to the pins 61/63. In the diagram those are labeled heat pump.



    In a bunch of other application diagrams, they show these connected to other aftermarket relays. I think that is a more traditional "call for heat in this zone" type system.

    I tuned this up over the years. The heated kitchen floor was a game changer. Instead of a cold drafty kitchen, its is the best room to be in when it is cold. I need to check how often the boilers run when its cold. But getting the 24/7 pump optimized will help a lot.
  • hot_rod
    hot_rod Member Posts: 17,531
    So the two large circulators the 43-75, they are just wired to a plug, running all the time? Where are they connected in the big scheme of things :)

    Best I can see is the boilers fire when outdoor temperature drops to a certain number, usually around 68F. Then the boilers and their pumps run until they reach temperature?

    Maybe someone with more Buderus wiring logic knows. Looks like a common Euro approach, although not ideal control logic when you have two additional circulators to run.

    My though would be to start the distribution and primary circulators only when the boiler is firing. Really no reason for them to run when there is no heating call or load.

    If there is no room thermostat input, what keeps the space from over-heating? Must be something connected to the brown "room sensor" terminal?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • hot_rod
    hot_rod Member Posts: 17,531
    The green Taco relay box, you just bought  what is connected to it? One or both circulators by chance?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    hot_rod said:

    So the two large circulators the 43-75, they are just wired to a plug, running all the time? Where are they connected in the big scheme of things :)

    The primary is connected to the wires 61 and 63. Run 24/7 by the logic. Actual 120v wires direct from the logic. Same with the secondary pumps.

    The other is an optional pump to speed it up. Power though a relay controlled by the extra Tstat. That one is optional. I used it from the legacy install.
    hot_rod said:



    Best I can see is the boilers fire when outdoor temperature drops to a certain number, usually around 68F. Then the boilers and their pumps run until they reach temperature?

    Maybe someone with more Buderus wiring logic knows. Looks like a common Euro approach, although not ideal control logic when you have two additional circulators to run.

    My though would be to start the distribution and primary circulators only when the boiler is firing. Really no reason for them to run when there is no heating call or load.

    I need to always more the water for this system. It is not a simple call for heat. If I set it up as a call for heat, it would take 60 minutes to get anything. Then overshoot for 5 hours after that. Too much water.
    hot_rod said:



    If there is no room thermostat input, what keeps the space from over-heating? Must be something connected to the brown "room sensor" terminal?

    This is a better diagram with the optional room sensor. In the photo, the brown terminal is connected.



    My gut tells me I only need a very small primary. I'm confident the primary is 24/7 in this setup. This setup avoids to legacy way to control the overshoot. They would just open a window in the winter to drop the temp.

    I might try the taco from the floor as a test one I replace that one.
  • Chris_51
    Chris_51 Member Posts: 46
    That is running the floor at my office. I need to get one like that for the home setup. For whatever reason, the logic doesn't generate 24v. It does Low voltage and 120, but not 24v. So there is a 50 year old inefficient transformer that used 20w
    hot_rod said:

    The green Taco relay box, you just bought  what is connected to it? One or both circulators by chance?

  • hot_rod
    hot_rod Member Posts: 17,531
    Chris_51 said:

    That is running the floor at my office. I need to get one like that for the home setup. For whatever reason, the logic doesn't generate 24v. It does Low voltage and 120, but not 24v. So there is a 50 year old inefficient transformer that used 20w

    hot_rod said:

    The green Taco relay box, you just bought  what is connected to it? One or both circulators by chance?

    All transformers are the same efficiency. I'd argue the 50 year old one is just as efficient as the day it was installed! Its just copper wire wrapped around an iron core, really.

    The Taco box you installed has a 10 or 12 VA transformer. The one you took out is a 40 or 50 by looking at it. So you just reduced consumption by reducing the size of the transformer.
    As long as it has sufficient Va for the job, you should be fine. Transformers, like pumps, get sized to the load they need to carry. The one in your relay box can only run the relay, some thermostats, no additional 24V loads.

    Back to the primary loop and its circ. That loop probably only holds what 10- 15 gallons. So starting that "loop" circ would bring the primary loop up to temperature within minutes.

    No harm in trying to start the primary when the call for heat comes on. Probably save you 4000 hours a year of run time on that circ. Over a 20 year span, that certainly seems worth it?

    More importantly would be constant circulation on the distribution circ to eliminate the flywheel effect to start and stopping. Depends on the heat emitters and how or if they are zoned.

    The pieces of this puzzle just dribble in so hard to say what are your options or best options.

    The more modern way of primary secondary, shown below, eliminate the "challenged" primary loop pump altogether. Known now as horseshoe, moose antler, or hydraulic separator piping.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    hot_rod said:



    All transformers are the same efficiency. I'd argue the 50 year old one is just as efficient as the day it was installed! Its just copper wire wrapped around an iron core, really.

    The Taco box you installed has a 10 or 12 VA transformer. The one you took out is a 40 or 50 by looking at it. So you just reduced consumption by reducing the size of the transformer.
    As long as it has sufficient Va for the job, you should be fine. Transformers, like pumps, get sized to the load they need to carry. The one in your relay box can only run the relay, some thermostats, no additional 24V loads.


    The one I took out was 40va. The Taco is 15va. I'd expect the Taco to be 6.66 w. But it is only 3. Something is going on there.
    hot_rod said:



    Back to the primary loop and its circ. That loop probably only holds what 10- 15 gallons. So starting that "loop" circ would bring the primary loop up to temperature within minutes.

    No harm in trying to start the primary when the call for heat comes on. Probably save you 4000 hours a year of run time on that circ. Over a 20 year span, that certainly seems worth it?

    More importantly would be constant circulation on the distribution circ to eliminate the flywheel effect to start and stopping. Depends on the heat emitters and how or if they are zoned.

    The pieces of this puzzle just dribble in so hard to say what are your options or best options.

    The more modern way of primary secondary, shown below, eliminate the "challenged" primary loop pump altogether. Known now as horseshoe, moose antler, or hydraulic separator piping.

    This all does help. Many thanks.

    I tried running the primary along with the secondary pump of boiler 1. It does work generally. I'm in the toughest temp range for testing tho. So rewiring does save a ton of power. I loose the old effect of a slow but constant flow through the house. I'll test more to see if that matters. A 24/7 pump that only draws 30w would be perfect.

    I did notice the secondary pumps are 3 speed and set to the highest speed. I might test those too.

    Thanks.

  • Chris_51
    Chris_51 Member Posts: 46
    The project is moving along.

    On the secondary pumps, they seem to work the same at medium speed. I'll try low.

    On the original kitchen floor, the new Taco is great. It dials into around 9w. So down from 97w. See pic. Interesting that on Amazon, the cranked the price of that one up $80 if I wanted to buy another for the bathroom.

    On the transformer, I can even find a 24v 15VAC transformer. A huge pain. I might just buy a use Taco and take the transformer out.

    On the primary / secondary, I was thinking of trying a much less powerful pump for the primary. I was going to try the old taco for a test. But it has much smaller flanges. I can't find an adapter. Is there such a thing? The taco is about 2 inches narrower than the Grundfos UP43-75F. With smaller flanges.

    I think I need to go back to a 24/7 pump for the primary. With the primary running with boiler 1, it high limits out after 10 minutes, then the primary shuts off. An efficient primary would be perfect.

    Is there a good online source for this stuff?


    Chris_51 said:


    I did notice the secondary pumps are 3 speed and set to the highest speed. I might test those too.

    Thanks.

  • hot_rod
    hot_rod Member Posts: 17,531
    Think of the primary loop as a conveyor belt, or people mover at the airport.

    Them only time it needs to be moving when people are on the loop, getting on or getting off. Same applies to that primary circulator.

    If for some reasons the boilers run they should just flow up into the loop back to the boiler, reach setpoint and shut off. As long as their circulators run, they should not go off on high limit?

    Even with that pipe insulation the primary loop is a heat emitter when the primary pump runs constantly. So it is costing you both electricity and gas to run the loop 24/7.

    Also, boilers should not fire and heat unless there is a heat call?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Chris_51
    Chris_51 Member Posts: 46
    Your comments did get me on the right track for the floor. Plus to troubleshoot the loop inefficiency.

    The last post for more ideas on where to buy parts - like flanges, pumps and transformers. I think I tracked down a local place, but I suspect they won;t have a 15 GPM ECM pump. I'll go over there soon to see.

    On this system, it is not a call for heat system. See attached. I mentioned this a few times. It has an outdoor air sensor. No need for that if it was just a call for heat.

    So leaving a ton of heat in the boilers and loop to just burn off overheats the boiler room. That needs to move out to the house loop to go somewhere in the house, bit the boiler room. It takes 2 hours or so to get any significant heat to the house. Then on days like today, where it goes from 45F in the morning to 70F in the afternoon. The 2 hours of running the boiler in the morning is enough for all day.

    Here are some docs on the continuous nature of this system.




    hot_rod said:

    Think of the primary loop as a conveyor belt, or people mover at the airport.

    Them only time it needs to be moving when people are on the loop, getting on or getting off. Same applies to that primary circulator.

    If for some reasons the boilers run they should just flow up into the loop back to the boiler, reach setpoint and shut off. As long as their circulators run, they should not go off on high limit?

    Even with that pipe insulation the primary loop is a heat emitter when the primary pump runs constantly. So it is costing you both electricity and gas to run the loop 24/7.

    Also, boilers should not fire and heat unless there is a heat call?