Boiler piping v1

Pulse

System specs:

• 8 zones, "homerun'd", with 12 panel radiators sized for 130 SWT on a design day
  
• Currently have a cross manifold planned, but could switch to zone values/actuators with TRVs
  
• Boiler will either be a US Boiler Aspen or a Lochinvar Knight
  
• Indirect and buffer will probably be a matched Lochinvar(squire)/IBC(interstor), or maybe a combo of HTP Ultra Max(indirect)/Heat-flo(H2-22 buffer)
  

Questions:

1. Any improvements/changes to the piping? Let me know whatever can be done better.
   
2. The majority of the piping I saw while reading idronics had the expansion/water makeup on the return side, but I see a lot of posts say I should have it where I have it in the above image?
   
3. Do you recommend putting unions basically everywhere?
   
4. Best zone circ? = Taco VT2218 or.. ?
   
5. If I go with the Lochinvar boiler, it comes with a Grundfos UPML 25-104/5. If I go with the Aspen, that does not have a pump, what is the recommend system circ?
   
6. Best indirect circ?
   
7. Recommended air/dirt separator? - Taco 4900 vs Caleffi Discal/Dirtmag vs Spirovent
   
8. I can easily go to an 85k boiler, but the price difference is ~100, and the min fire of 11k vs 8.5k doesn't matter because I need a buffer anyway. So, I figured why not have more DHW?
   

Thanks

hot_rod

A vertical air sep just under the boiler assures all circuits run across the air sep.
With all those checks you show I'd put the expansion tank on the blue pipe by the indirect. So you don't check the expansion tank out of the boiler circuit.

The fill valve connects where the expansion tank connects.

Any of the ECM delta P type circs would be my suggestion for a zoned system

Since you show 1-1/4" pipe to the indirect, it could take the full output of an 85- 100K boiler. With the correct pump.

Both the indirect manual and the boiler manual should show pump requirements and sometimes model number options.

Pulse

hot_rod said:

A vertical air sep just under the boiler assures all circuits run across the air sep.
With all those checks you show I'd put the expansion tank on the blue pipe by the indirect. So you don't check the expansion tank out of the boiler circuit

So, location 1 or 2?

hot_rod said:

Any of the ECM delta P type circs would be my suggestion for a zoned system

Alright, exchange the VT2218 for a taco 0015/0018/grundfos alpha

hot_rod said:

Since you show 1-1/4" pipe to the indirect, it could take the full output of an 85- 100K boiler. With the correct pump.

Both the indirect manual and the boiler manual should show pump requirements and sometimes model number options.

I havent seen any offer actual model numbers, but as long as I am meeting GPM/head requirements, should it be a 3 speed/variable speed circ?

Teemok

Expansion and fill on back side of the primary pump. System pump is a confusing term. I see it used for both primary and secondary positions. Analogy: Entree is a term coming from music. The opening act. It is correctly used in France as the first course but in America we use it to mean the main course. Solution: don't use the term at all to avoid confusion. Technically if it's in the system and it's a pump than it's a...... system pump. Boiler or primary pump. mho. Pumps pump to the largest head resistance in your case that might be right as it is. Zone or secondary pump is ecm variable. Most pumps have checks in them yours may not. Good quality externals checks in serviceable arrangement are preferred. I don't think you need both. The ones in pumps do work. The buffer tank is a great air sep. so move the other sep. to the indirect return or omit it if piping permits natural venting to the boilers air vent. Dual exp. tanks? Don't see why. You may need a DHW exp. tank.

Teemok

You will be tuning circuits for low flow and high deltas T's for each radiator. Either at the mani. or at a rad. valve if there are more than one piped paralleled on a single zone. A constant pressure ecm Taco or Grund. that can move .5- .7 gpm for each radiator with all zones open. This rarely happens but it's best to design for it. The primary pump should be fixed speed and as small as can be while meeting min flow needs. You don't want to stir the tank. A 15-58 on low or med. depending on boilers head. DHW pump depends on total head of the boiler ind. coil and piping and if you want fast recovery or best efficiency. There is a min. flow to be met. OD Reset the radiators and play with numbers finding your homes ideal lowest temps.

Pulse

Teemok said:

Expansion and fill on back side of the primary pump. System pump is a confusing term. I see it used for both primary and secondary positions. Analogy: Entree is a term coming from music. The opening act. It is correctly used in France as the first course but in America we use it to mean the main course. Solution: don't use the term at all to avoid confusion. Technically if it's in the system and it's a pump than it's a...... system pump. Boiler or primary pump. mho. Pumps pump to the largest head resistance in your case that might be right as it is. Zone or secondary pump is ecm variable. Most pumps have checks in them yours may not. Good quality externals checks in serviceable arrangement are preferred. I don't think you need both. The ones in pumps do work. The buffer tank is a great air sep. so move the other sep. to the indirect return or omit it if piping permits natural venting to the boilers air vent. Dual exp. tanks? Don't see why. You may need a DHW exp. tank.

I honestly didn't know what to label that circ, haha..will call what I have labeled "system", primary from now on

There is just one expansion tank, the other one, near the top of the indirect is for domestic.

Teemok said:

You will be tuning circuits for low flow and high deltas T's for each radiator. Either at the mani. or at a rad. valve if there are more than one piped paralleled on a single zone. A constant pressure ecm Taco or Grund. that can move .5- .7 gpm for each radiator with all zones open. This rarely happens but it's best to design for it. The primary pump should be fixed speed and as small as can be while meeting min flow needs. You don't want to stir the tank. A 15-58 on low or med. depending on boilers head. DHW pump depends on total head of the boiler ind. coil and piping and if you want fast recovery or best efficiency. There is a min. flow to be met. OD Reset the radiators and play with numbers finding your homes ideal lowest temps.

I have all the panel rads on their own home run, even if two are in a single zone. Is parallel piping for two, in a single zone, better?


You would pipe it like this?:

hot_rod

Where you install the expansion tank into a system, that determines, or becomes the primary loop. So if the tank was in either vertical pipe under the boiler, the boiler loop is primary.

If the tank is in the horizontal piping between buffer and indirect, that becomes the primary and the boiler is then a secondary loop.

Some boilers ship with a pump and Lochinvar Knights for one have a variable speed operated "boiler" pump. Controlled by the boiler control to maximize condensing, lower the return.

A two pipe buffer tank is known as a direct to load piping arrangement.

If both the boiler pump and the zone or distribution pump are moving the exact same gpm, there is no flow into or out of the buffer.

So flow into and out of the buffer changes. Changes a lot on multi zoned systems.

Your indirect is a parallel load. The boiler pump does not run and the buffer is not involved.

A good air purger has a media inside to grab the tiny dissolved air bubbles, a good option even with a buffer tank. The buffer is a good low velocity zone for removing air, have a float vent up top if possible.

At the hottest point in the system, right at the boiler supply pipe is the best location for air removal

Teemok

All home runs is great. Parallel is possible to do but is an added tuning complication.

@hot_rod I always considered the heat source loop primary but with multiple heat sources that goes out the window. I see that a boiler loop is not necessarily the primary loop. I'd never call an indirect loop primary if there was any other load. Thanks.

Teemok

The point about media in the sep. being superior is valid but I've found a buffer tank to work very well. The part becomes a bit redundant. Putting it on the DHW loop is over kill for the volume of water in that loop. If the DHW coil is below the boiler and has no air traps, simplicity wins and it can be eliminated completely. Micro bubbles will leave via the buffer. I've piped systems very similar to this design and had them start up and run with no bleeding bar the tops of radiators.

Teemok

I was looking at the wrong diagram. I missed that you already had the DHW exp. tank. What you have labeled as a backflow preventer near the DHW mix valve cold is just a spring check and I would put it just after the iso. valve on the cold before the mix valve branch. If you are on a well both check and exp. tank may not be needed. I see no recirculation line. Is there none? If there is a recirc. I like to feed the mix from a high position hot line loop (heat trap) If I can. I like iso. valves with bleed ports on the on exp. tank side or boiler drains and a union if you're feeling rich. The iso.'s on the boiler are not really needed. I wouldn't union if I could leave some pipe to cut and fit them if needed later. The zone pump should have iso. valve flanges on it (Webstone valved flanges) The return side of the zone/secondary might have an iso valve with bleed port. The iso.v on the DHW coil "in" is useless if there's not a check in the pump or an iso. v. on the return. Logic check how you would change/work on each pump and if you needed to iso. the DHW coil if it leaked and wanted heating to still work or vice versa .

BrianBee2501

Referring to the diagram above, would this set-up work if I were to use a Grundfos 43-75 pump on the indirect water heater and a UPS 26-99 on the buffer tank loop?

Pulse

Original with some changes. @hot_rod, to confirm, you say if I have the expansion tank on the horizontal piping, like above, this makes my indirect the primary? Confused why the horizontal/vertical piping matters.



Since both the aspen and knight can be top/bottom piped, this may also be an option

---

@Teemok
City water, no domestic hot water recirculation

hot_rod

Need to know which boiler you will be using to select the pump. I think both the 43-75 and maybe the 26-99 will be over-sized. Especially if that is a fire tube boiler design on the Lochinvar? The boiler manual has the spec for the correct pump, as will the indirect installation manual.

I'd need to know the boiler, the indirect, and a bit about the piping.

My suggestion for the alternate expansion tank location has to do with dynamic pressure in the system with those large circulators. The expansion tank in the wrong location you could pull the system below static fill, possibly into a sub-atmospheric condition withn a large circ, due to the pumps ∆P.

This article shows and explains it best. You could build a graph like this to predict your systems operating condition. This theory gets a bit complicated

https://www.pmmag.com/articles/83943-picturing-p-br-john-siegenthaler-pe

Teemok

I like the supply out of the top through air sep. and down to a T and both returns to the bottom. Checks the in pumps or not? If the whole system is new, a dirt sep. is over kill but a Y strainer is good to have. Don't forget tank drains.

Teemok

15-58fc is the CH factory primary. A 26-99 3speed on med for DHW primary for most 40 gallon indirects. (14 gpm @ 8-9ft total head Knight/Squire) 15-58's Can do it but will only push 9-10 gpm in the DHW position. Works well enough. Slower to get the BTU's to the cold tank water but more efficient.

hot_rod

You only get a high efficiency system with both high efficiency boilers and high components. Efficient pumps and high efficiency separators.

Any system with ECMs should have a dirt sep with a magnetic function. 70% of returned ECMs are jammed with magnetite. The pump becomes the magnetic separator. Magnetite exists in all systems that have ferrous components, pumps, expansion tanks, etc. You will see this the first time and every time you blow down a mag sep.

Same for air, any micro bubbles in the boiler or heat emitters reduces heat transfer from the fluid to the metals. Micro bubbles form when the burner heats water in the boiler. They go in and out of solution as the boiler heats and cools. Unless eliminated with a coalescing type media.

No need to scrimp $$ on the best components for that expensive, high efficiency system.

Y strainers, that are doing their job, reduce flow from day one and continue to do so, as they rarely get serviced.

Some graphics to show how air separates in hydronic systems.

BrianBee2501

This is the pump layout I was considering without the extras.

Teemok

@hot_rod Thanks for the above info. Heard. I'll DM you questions to not mess up this thread..

Teemok

@BrianBee2501 Pipe boilers in parallel (as you have kinda) in and out of the buffer tank. supply in goes hi, return low. Melt pump (missing) must meet head and flow needs of the melt zone. If a 26-99 does it, than it goes on high buffer outlet port pushing out. I would Pipe the DHW tank with just one boiler piped as a second parallel primary pump mounted on the return. 26-99 might be just big enough depending on what tank and boiler. Air separator on the supply to buffer, air vent on top of buffer, water Fill and expansion tank on return piping before the boiler pumps.

BrianBee2501

Thank You, I will consider your suggestions

hot_rod

Is the entire system buffer included going to be glycol? $$
Since you show some snowmelt.
A plate HX could be used to separate the glycol system.

Or maybe a boiler dedicated to the snowmelt. Is that a 500,000 btu/hr, 5000 sq ft, snowmelt design?

What is the house load?