Replacement circulator help?

Teemok

Maybe @hot_rod can talk about best placement for you. I put one on the return of a system a with Iron pipe and radiators. I put another on the supply after the pumps that were the only iron in the system.

hot_rod

I promote air seps at the boiler outlet, the hottest fluid, mag and dirt on the return

northlakes

mattmia2 said:

The head of larger diameter pipe per foot is less, you should calculate it in sections.

You would only use the longer half of the split loop, that is the idea of the split loop, it can keep the head lower with smaller pipe by feeding the loop from the middle.

Thank you! I will recalc based on this much larger trunk section.

northlakes

hot_rod said:

I promote air seps at the boiler outlet, the hottest fluid, mag and dirt on the return

I'm looking at this, to install in a 1" return pipe right before the boiler (primary loop) pump.
https://www.supplyhouse.com/Caleffi-NA545396-1-DIRTMAG-Dirt-Separator-with-Magnet-Union-Sweat

This model appears to be rated for 10 gpm, Is this a problem if the max flow of the entire system is calculated at 16.4, or is the flow capacity varying at different points in the system?

hot_rod

I would steer you towards the brass version, can you get it into a horizontal run somewhere?

That rotating collar design adds some restriction.

northlakes

A re-pipe looks likely, The 1" brass dirtmag is rated for 14 gpm, so all I can think is to upsize a section of that re-pipe in primary loop to accommodate a larger 1 1/4" unit. Only other place I have a horizontal run with access would be further back past shutoff in secondary 1 1/2" trunk of the return.

hot_rod

Are you sure about that 16 gpm?
you mentioned 315’ of fin tube. Does that match a heat load calc

Teemok

This is primary secondary piped right? What size is that Taco pump in the boiler loop? Is it multi speed? The 199 boiler would be fine with 14 gpm in the boiler loop. Is the boiler loop 1-1/4" that would make max flow 16.3 gpm. You can limit the boilers max firing rate if you want to but I don't think you would need to.

northlakes

Teemok said:

This is primary secondary piped right? What size is that Taco pump in the boiler loop? Is it multi speed? The 199 boiler would be fine with 14 gpm in the boiler loop. Is the boiler loop 1-1/4" that would make max flow 16.3 gpm. You can limit the boilers max firing rate if you want to but I don't think you would need to.

Yes primary secondary. it's an 0015e3, it's got low-med-high speeds. Primary loop has a combo of 1 1/4" and 1", secondary goes up to 1 1/2" for the trunk sections. I'd have to re-pipe either way if I can't use the vertical model (10 gpm.)

northlakes

hot_rod said:

Are you sure about that 16 gpm?
you mentioned 315’ of fin tube. Does that match a heat load calc

This is where I get confused. Slantfin heatloss calculator I used before has gone extinct but my initial calc came to 105k. I padded 315' of emitter because I have several runs of bare pipe in enclosure, without that padding it came to 15.8 gpm max flow based on emitter length alone. I'm unclear on how heat load is figured I think.

If it matters for context the total heated is closer to 5000 sq ft., 2000 of which is about 3/4 below grade. A large building at a high spot with high wind exp. on top two floors which is why I'd assume installers have tended toward a larger system. It's also an odd microclimate with colder temps, and a lot more snow than the towns a few miles down the hill. While our county level shows 99% at -1F, It's much colder than that at least a week or two mostly every winter (our weather station is in a warmer spot.) That said decent wall insulation and double pane windows on a 120-yr old home holds the heat better than I originally expected. Biggest leak is definitely the attached garage door (heated garage/workspace.)

hot_rod

You can work the two together, the heatloss calculation result and the amount of radiation 

If the home has always maintained a comfortable temperature that indicates you have ample heat emitter. Maybe more than you need which is why the heat load number reconciles the answer

How many feet of actual finned tube? Don’t count bare tube in enclosures 

WAG from the square footage
 you indicated, you are closer to 105  than 165
So that makes a big difference in pump sizing

Try the load calc calculation again. I use Heat Load Pro at www.hydronicpros.com
There is a free demo, maybe you can do the entire load again with that program

Basically the load calc determines all the exposed surface area walls, windows, roof. Their r value then the temperature differences between outdoors and indoor

northlakes

hot_rod said:

WAG from the square footage
 you indicated, you are closer to 105  than 165
So that makes a big difference in pump sizing

Try the load calc calculation again. I use Heat Load Pro at www.hydronicpros.com
There is a free demo, maybe you can do the entire load again with that program

Basically the load calc determines all the exposed surface area walls, windows, roof. Their r value then the temperature differences between outdoors and indoor

Sorry, what is WAG? A guess? I'll look into the software you're talking about but don't have a windows computer so I'll see if I can run in VM

Teemok

That 0015e(ECM pump) is not moving more than 14 gpm. Max safe flow for 1" copper is 10.9 gpm. hot_rod wants to make sure your heat load and emitters match the boiler room. I agree, know what the space needs, compare that with the emitter output capacity, then you will know what has to be in the boiler room. Slowing down the boiler loop could be a limiting factor for btu output. Trying to catch partials at max velocity isn't the best either.

hot_rod

Well if you want old school
https://www.pprbd.org/File/Resources/Downloads/ResidentialHandout/Heat_Loss_Table2011.pdf

Load calc programs are all based on Manual J, so you could use this  form, a tape measure and calculator

northlakes

@hot_rod Used the Heat Load Pro demo, and ended up with different results than the slantfin calculator I used a while back. It's an older house so added some padding as many walls have unknown insulation, some areas are a bit leaky, then added 20% to the total, as our wind exposure is constant/intense. (convinced this has something to do with the reason installers seem to spec bigger equipment here...)

Still only ended up with 90k, 15k lower than the other calc.

Just looking at the size of the building at 4200 sq ft of heated space I guess that still feels low, but I double checked my math in the software and it looks right. Maybe not using the software correctly? Or maybe dramatic oversizing here is just due to epic winters...

So if I have 315' of emitter, I guess I'm still confused on how that figures in, which according to these calcs appears to be more emitter than I need, but doesn't the length still figure into gpm?

Teemok

I'd say on coldest windiest days you might need most of that 315' @ 180F. I use the 500btu/ft spec that means you have 157.5K of fin output. 4200 sqft building using the quick reference only "dull tool method" 40 btu per sqft is 168k. The truth is likely somewhere well below 168K like your calc's indicate but for worst case wind infiltration you are covered. I think you should design to be able to move close to the 16 gpm max in the distribution loop when all zones are calling for heat. Your 1" boiler loop piping maxes out at 10.9gpm The sl IBC can use a distribution loop sensor that they call a secondary loop sensor ( @hot_rod with no regard for where the expansion tank and fill valve actually are ) Enabling and installing this sensor (you may already be using it) the boiler will fire using the secondary loop temp. as the target for it's burn rate and thus the boilers delta T can be 30F. 160F in and 190F out @ 10.4 gpm is 156k delivered by the boiler. Imho a 0026e and a mag filter would be good. The system looks reasonable if just under velocity limits using worst case logic and assuming balanced branches and emitter loading. A good outdoor reset curve might save some fuel in the shoulder seasons. Let's see what hot_rod thinks.

hot_rod

The heatload  calculation is just a snap shot in time. You may never be at that exact condition

if you live in an area with high wind conditions, take that into account for the infiltration number

If that is a big unknown, a blower door test could zero in on an actual number and also indicate  where the leaks are.

That may be money well spent, instead of heat that you pay for going out the openings for the life of the building

Go to the NORA site and look back 30 years to see the average number of days you are at or below design condition.

The house, the structure, dictates the load.

Teemok

Wait.... are you solving a system performance problem? The structure is uncomfortable? I though you needed a pump replacement. You can always make a tighter envelope to reduce heat load. Calculations are great for predictions or problem identification or verification but if the structure already stays nice and warm on the coldest days what's the numbers crunching about?

northlakes

Ha, I’m just trying to size a pump. And following the generous advice here. I thought the idea was that I needed an accurate calc because my gpm was derived from actual feet of emitter and that a heat loss calc would somehow verify I was in the right ballpark for pump size.

. 

Robert_25

northlakes said:

@hot_rod Used the Heat Load Pro demo, and ended up with different results than the slantfin calculator I used a while back. It's an older house so added some padding as many walls have unknown insulation, some areas are a bit leaky, then added 20% to the total, as our wind exposure is constant/intense. (convinced this has something to do with the reason installers seem to spec bigger equipment here...)

Still only ended up with 90k, 15k lower than the other calc.

Just looking at the size of the building at 4200 sq ft of heated space I guess that still feels low, but I double checked my math in the software and it looks right. Maybe not using the software correctly? Or maybe dramatic oversizing here is just due to epic winters...

So if I have 315' of emitter, I guess I'm still confused on how that figures in, which according to these calcs appears to be more emitter than I need, but doesn't the length still figure into gpm?

Your numbers seem reasonable to me. I am heating about the same amount of old house on the Canadian border. When I did a heat loss with the Slant Fin software it was roughly 100k btu/hr, and based on boiler run time I have never gone beyond 80k btu/hr.

northlakes

I’m still still confused on what I do with this number that represents feet of emitter, do I discard that and use the heat loss calc to figure gpm?

Robert_25

The heat loss figure is most useful for sizing the boiler and boiler circulator, but it can also help determine if you have "ample radiation" and don't need to be at the high end of the flow rate for the radiators.

northlakes

Robert_25 said:

The heat loss figure is most useful for sizing the boiler and boiler circulator, but it can also help determine if you have "ample radiation" and don't need to be at the high end of the flow rate for the radiators.

Thank you, this makes sense!

Teemok

Each 3/4" copper branch wants no more than 4gpm. 6.5gpm is the maxed out safe flow rate for 3/4" copper pipe. Flows faster than 4ft per sec. means more noise and pipe erosion. You don't want that high of a flow if you don't really need it. That means the pump you get should be ABLE to move a over 16gpm at the head loss of the longest branch. 16gpm is your target total distribution flow rate. The max is closer to 25gpm. Because of the 4 gpm per 3/4" branch flow rate limit you should not have more than 35-40kbtu's of finned emitter on one 3/4" piped branch. You have 315' total of finned emitter. @180F supply water temp. 3/4" finned emitter puts out around 500btu's per linear ft. 80' of 3/4" fin tube emitter = 40kbtu's per branch while creating a 20F delta T between the water entering the branch (180F) and exiting (160F). My uncle taught me 65kbtu is the max ever on a 3/4" pipe @180F. If you have more than 80' of emitter on some branches the overall system output capacity drops some and the delta T's of the overloaded branches get bigger than the standard of 20F. If you know you have three 3/4" branches with 100' of emitter on each, you know the emitters on the end of these branches will have less output than ones at the beginning. Not a big deal unless you need every btu you can get out of those last over loaded ft. of emitter. That's when you can compensate by pushing flow rates beyond ideal targets and closer to the limits.
What you want is an ECM pump that can provide the max flow if it's needed and also has the flexibility to slow down flow when 3 of the zone valves are closed and only the wild loop is circulating. You don't want much more than 4-5gpm flowing through any one of these 3/4" branches when all or most of the zones are closed. You may not ever need max flow. It's better to be able to turn your pump up to a higher setting than it is to find the pump is too small to deliver what's needed. Some people change their pumps settings seasonally. Cold months get a higher flow setting.
Tuning: You can change the flow rate and or the temperature of a system to tune to the structures needs. You can choose to always exceed the flow and or the temperature needs of the structure and be a little less efficient or you can try to tune closer to the heat loss of the structure to save some energy. Outdoor reset ties the supply water temperature to the outside conditions. As it gets colder outside water gets hotter in the system. I gotta stop writing these long comments.

northlakes

Teemok said:

What you want is an ECM pump that can provide the max flow if it's needed and also has the flexibility to slow down flow when 3 of the zone valves are closed and only the wild loop is circulating. You don't want much more than 4-5gpm flowing through any one of these 3/4" branches when all or most of the zones are closed. You may not ever need max flow. It's better to be able to turn your pump up to a higher setting than it is to find the pump is too small to deliver what's needed.

I appreciate the comments. And sorry I keep getting confused... but from the heatloss calculated ~100k BTUH, I end up at 10 gpm, with emitter length calc I end up at 16 gpm. Are you saying I need something that "could" pump 16gpm? For instance the Grundfos Alpha ALPHA 15-58F is seemingly right-sized for 10 gpm and 8.2 max head. Would this be underpowered because of the emitter length?

Robert_25

How much emitter is on each zone?

Teemok

You can exceed the flow needs of a branch as long you aren't approaching the flow limits of the pipe. Lower the flow to 2.5 gpm per branch and each branch is good for 25k. You've never said how many ft of emitter is on each zone. How many emitter feet are on your wild zone? 10gpm x 500 x 20F = 100kbtu. Why would you buy a pump that has a max. heat delivery capacity of exactly the structures calculated loss? You have an old house in a cold climate in a high wind area. I would suck to be cold because the pump you go with is the limiting factor.
Your existing pump is way bigger than that. Give yourself some excess capacity. An ECM pump that can pump 18-20gpm @ 8Ft would be ideal. Unfortunately your ideal sized pump falls right between the ECM pump sizes made by Taco and Grundfos. I suggested the 0026e because when it's on auto-adapt it will turn down low enough and also has plenty of capacity when it's needed. Because your wild zone pump runs all the time any electrical savings is adding up 24hrs a day.
Because you are zoning with valves it looks like you would need a differential bypass valve if the pump you use is 18gpm @8ft capable and is a non-ECM.

northlakes

Ok I see what you are saying, so then maybe the 0026e is still the safest choice. I assume this still means that even though a safe flow for 1" pipe is 10.9 gpm (my current vertical pipe option in primary loop), that a 10 gpm spec on dirtmag would be too low. Again, my assumption would be the the primary loop doesn't have to match the max flow of the distribution loop, but maybe that's been an incorrect assumption.

Emitter by zone
Zone 1: 48’
Zone 2: 112’
Zone 3: 81’
Zone 4 (wild loop): 74’

Teemok

I mentioned the IBC secondary loop sensor in a previous post. You can have a lower flow in the boiler loop with a higher delta T and get the heat out of it. Example 10gpm x 500 x 30FdeltaT= 150,000 btu/hr. A 20F deltaT is: 10gpm x 500 x 20F deltaT = 100,000 btu/hr. You may not need 150k but there's a way to get it out of the boiler with 10gpm if needed. Pushing over the 10.9gpm flow rate in 1" copper near boiler pipe is a lower risk, in that, it's accessible and can be re-piped in 1-1/4" should it be a problem. Let's say your are moving 12gpm in the boiler loop: 12gpm x 500 x 20F deltaT = 120,000 btu/hr. Your boilers 0015e likely only needs to be on low, maybe medium speed to move 10gpm. A mag.filter can be installed anywhere in the system and it will pull magnetite out. A loop that has regular use would be best. Maybe your wild loop has a good spot to fit it. Looks like zone 2 can use 5-5.5gpm. The 0026e will need the pump flange spacing changed so maybe getting the boiler loop upgraded to 1-1/4" and fitting the mag. filter somewhere in a loop in one event would be good.

northlakes

Thanks much, looks like a good plan.

northlakes

Did some re-piping, replaced the secondary loop circ, added dirtmag, repiped expansion tank.

Had trouble purging as usual, but after a day the air sep seems to have done the job and all seems to be working well, trying out the auto-adapt function on the Taco 0026e. Seems to be working fine but I'm not entirely sure how to measure that. Ramps up to higher speeds with more zones open. Now, go figure, boiler pump is now rattling. Maybe some solder got into the pipe... no idea.

System baseboards also seem to be picking up some harmonic vibration they didn't have with the old pump, when running at the lowest speed. Doesn't seem too bad at the boiler room, and new pump isn't loud or anything. I can feel a slight vibration that maybe wasn't there with old pump. Wondering if the lower pump speeds generate more vibration, or if the repipe and new pipe hanger attachment points changed something just enough...

Purged and opened fast fill on PRV, after closing the fast fill and purge valves it overfilled and the boiler relief blew. Drained primary loop again and pulled the expansion tank (a few months old) and it wasn't waterlogged or anything, put a gauge on it and it read 13 psi. Wondering if this PRV (a few months old) got stuck open or something, as the flow doesn't seem to change when I move the lever back and forth with water flowing through, and not much resistance on the handle. So I closed the shutoff downstream of this PRV (when I do this the handle does have resistance again) and system pressure gauge stays at 16 psi. Backflow preventer seems to generate a very slow/small droplet, don't know if that means anything.

hot_rod

A solder ball in the pump impeller can cause vibration. 

There are some noisy ECMs out there a wholesaler told me last  week.

northlakes

After adjusting pressure screw in the PRV it magically fixed the fast fill being stuck open (lever has resistance again) but it still appears to leak, as pressure rises over several minutes and doesn’t stop. For now I’m just keeping the shutoff closed. 

Wondering if I should eventually replace with the same B&G PRV or if a different valve is a better choice. Valve is only a few months old.

Will also pull the boiler pump at some point to see if I can track down the rattle.