Low Loss Headers & Close Coupled T's

ecowarrior

I am Heating Engineer from the UK. For larger domestic properties we use low Loss Headers but I have read some really interesting articles from the US about your method of Hydronic Separation using close coupled T's. Is this the right forum for engaging with this sort of question? In The UK we need to be registered before allowed to play with gas & need a gas registration number to join a UK gas & Heating forum - is it the same with you guys? This is the sort of thing I would do but the header takes up loads of room (not an issue in this case) but Close coupled T's appear a lot neater & do the same job?

kcopp

This website it is a lot more friendly... anyone can ask questions. Close coupled tees will do one function that a Low loss header will do/ The LLH will do more and frankly do a better job than simple tees. They will also help w/ air elimination and in some cases, dirt separation. What boiler is that? Looks like a Triangle tube Challenger boiler they sell over here.

jonny88

This will get a lot of attention on the site and welcome.I find when doing a primary loop with closely spaced tees,it take up a lot of room.In my primary loop I will have a spirovent a primary loop circ and a magnetic dirt seperator.Isolation flanges are also installed on circ.Now come off your tees and pipe in your zones both supply and return.Starts taking up a lot of wall space.I like a 8 foot wall if available for boiler piping and spacing between circs etc although it can be tightened up a bit.As kcopp mentioned a LLH will provide all these functions and eliminate wall space as we all know boiler rooms are always the last thought and you gotta get creative .This site is very friendly and comes to the aid of a lot of homeowners who may have problems with their heating systems etc.Browse around and enjoy there is a lot more on the site than the wall check out the tool bar on top and you will get info on all kinds of heating systems both old and new.

ecowarrior

kcopp said:

What boiler is that? Looks like a Triangle tube Challenger boiler they sell over here.

Its a Dutch Biothermic boiler called an Intergas. One huge plate heat exchanger for both CH & DHW. Very simple only 4 moving parts with no secondary Plate Heat exchanger for the DHW (hot water)

ecowarrior

I stumbled over a (presumably) US firm 'Caleffi'. They do some brilliant tech publications and it was from these I grasped your CCT idea. Converting your Imperial to our now Metric is clumsy as the figures you use don't mean anything much to me if I had calculated them totally incorrectly! lol
our Natural Gas pressure here is 20Mb (milliBar) That equates (I think ) to 0.029psi - is this about what you use? Our bottled gas (propane) is obviously higher at 37mB.

ecowarrior

Just had a look at 'Triangle tube Challenger' and yes it is the same thing! Here in the UK ACV specialist in tank in tank water heaters & buy this from the Clogs (Dutch) and re-badge it as their own.
I see this site has a US spell checker - I think I will just give into that and speak US!

Paul48

eco........Could you strip that install down a bit for us? There appears to be some things done, that are not done here. Although it is difficult to see with so much going on. It's nice to see how you guys/gals do it across the pond.

Gordy

Welcome! It's funny to hear from across the pond that one would want to go the path of closely spaced t's . Here we are trying to encourage the path of hydraulic separators due to their multi faceted function verses closely spaced t's.

ecowarrior

A large (for the UK!) house with four teenage girls +M&D. requirement was for 'endless hot water' for morning showers & of course heating. Heating was split into 3 zones, main house, granny flat (small self contained area for the nanny to live) and the large kitchen diner that being the communal room.

So - Two combi boilers with the O/P into a header. However before it reaches the header there is a diverted valve ( 3 port) giving priority hot water to the 350 Ltr cylinder (about 70 gals)
The lead boiler will service the coil on the fast recovery Cylinder (28Kw)) However the lag boiler will give hot water to the kitchen sink or the nanny flat should the call come.

On hot water satisfied the 3 port valve swings over to heating and offers heat via the header to the three heating zones.

This was at the beginning of an eco requirement for energy saving pumps (circulators) so as the three zones were not that big I opted for one pump & three zone valves.
The boilers sequence & cascade in the normal way on heating.

ecowarrior

The heating runs on outside weather compensation with reduced flows down toi 40 deg C but on call to DHW the boiler is programmed to roar up to max (predetermined to match the coil Kw size) output & not modulate until it is satisfied. old on off cylinder stats cause to much boiler cycling so a ntc (sensor) is used to control modulation down to off , just as it reaches its cylinder setpoint.

jonny88

Caleffi is a great product Italian if I am not mistaken but on the top end as far as products go here.@Hot Rod could you chime in please.

ecowarrior

jonny88 said:

Caleffi is a great product Italian if I am not mistaken but on the top end as far as products go here.@Hot Rod could you chime in please.

Not sure what 'chime in' means?

Gordy

Drop in on this thread with some input. @Hotrod works for Caleffi. Also on of the most insightful hydronic specialists in northamerica, and beyond.

ecowarrior

Gordy said:

Welcome! It's funny to hear from across the pond that one would want to go the path of closely spaced t's . Here we are trying to encourage the path of hydraulic separators due to their multi faceted function verses closely spaced t's.

I have a job (hopefully) coming in a very old manor house. ( very small Downton abbey type dwelling lol)
It has 100 years worth of add ons from 2" lead pipe to 2 x 10 yr old non condensing boilers at either end of the property feeding holy moley knows what! Oh - and an AGA coal fired range running a few rads as well.
Where the want the new boilers is the smallest boiler room ever so I was trying to understand your method as maybe an alternate the the LLH ( first choice over here) to reduce clutter. Would need about 80 -100Kw so looking at 2x 40Kw on a header or CCT's
I note your headers are all symetrical - in flow & outflow oposite. Over here we seem to have all sorts of formulas for staggering them plus having the circuits coming straight out of them. Your data suggest keeping to primaries on the CCT as short as posible - where I was maybe thinking of remoting this pipework away from the boilers to utalise all the available space. All food for thought!
Also u use faster velocity than us thru the header . u r 2-4 feet per sec - we are about half that with one firm recommending 0.1 Meter per sec which equates top 4 inches per sec?

Gordy

Always interesting to hear methodology from across the pond. We tend to look over to across the pond, and think we are behind as a comparison of our means, and methods. Example being Min. flow rates to keep air in solution to get back to the air seperator for removal.

Interesting thought though on the remote P/S piping. But if you can remote that, and all associated hardware why not a Hydro Sep?

ecowarrior

Gordy said:

Example being Min. flow rates to keep air in solution to get back to the air seperator for removal.

Interesting thought though on the remote P/S piping. But if you can remote that, and all associated hardware why not a Hydro Sep?

Maybe the pioneers over here try to keep the flow temp down to below 60 most of the time (with weather comp & over sized radiators to keep return temps below dewpoint) helps reduce the air separating in the first place? Soluble Oxygen starts to gather at about 60 degrees IIRC. not sure to be honest.

As to your second comment - I am just exploring all the possibilities. I try not to go to a gunfight with a knife!!

SWEI

Closely spaced tees can often be the best answer when there are multiple supply or emitter temps. Placing them in series in the correct order allows the system to work much better than if they were all drawing off a single temp.

hot_rod

As I understand may of the systems in the UK are open, pressurized only by a tank up high in the building. if so magnetic separation becomes another important function, which can be accomplished by a air or dirt, or hydro-separator.

Caleffi does have a branch in the UK called Altecnic, contact Gary Perry at that office, maybe he can steer you towards a great system..

http://www.altecnic.co.uk

ecowarrior

So - heres my understanding - primaries to CCT as per normal flow rate (1.5lps) At the CCT it turns into 'common piping' with a flow of 2-4 ft per sec (0.6mps (much faster than our headers that are calced at 0.3 mps)) so pipe sizing (next available size up) is 67mm (Actual Velocity in Meters per sec = Flow (in LPS x 1000/ π r2 ( r= ID or bore of pipe) , so 0.38 mps (I'm happy with that)
so if that all sounds correct and as I am on reasonably small loads per cct I assume this will still work if I draw only 2 secondary (flow) mains from the common pipework & size 2 modulating pumps in stead of four pumps? ( each cct to then be controlled with zone valve)


Note I have made the pipework vertical with air bleed at the top & dirt collector at the bottom?

I see the word 'furnace' often. in the UK a blacksmith has a furnace & u smelt steel in a furnace - what do u call a furnace?
In domestic we have three boilers. Open Vent - just a heat engine no pump, to go on a vented system (old +needs a cylinder for Hot Water) )
System boiler which runs on a closed system & has the pump integral (needs a cylinder for Hot Water normally fitted to larger properyies that a combui cant cope with - multiple bathrooms etc) and Combi that is a system boiler that also produces DHW on demand normally mat about 40Kw. I imagine you are all asleep at the mo lol.

SWEI

Are you aware that the drawing above will produce unequal flow through the two boilers?

You would need to bring each boiler back to the same trunk using two pairs of tees, or (alternatively) pipe the boilers using a reverse return configuration.

Your might want to consider something like a Caleffi HydroLink for that system.

ecowarrior

SWEI said:

Are you aware that the drawing above will produce unequal flow through the two boilers?

You would need to bring each boiler back to the same trunk using two pairs of tees, or (alternatively) pipe the boilers using a reverse return configuration.

Your might want to consider something like a Caleffi HydroLink for that system.

Yes - slip of the pen there the reverse return is the usual here. To busy looking at the right hand side

If I used two CCt's would all four be together two flows & two returns?
Do you see any issues using just the two pumps?
I will b tight for space so having the common pipework running vertically in the corner of two walls would be a result. Hydrolic separators can be very cumbersome to fit at times.

ecowarrior

Is this an appropriate way to join the primaries to the commons?

Rich_49

That will work .

Tom_133

Rich, I may be way off here but I didn't think that last pic would work. I would separate those two sets of closely and pipe it supply return of boiler one, space accordingly, and then add supply and return of boiler 2. As I said though I could be wrong.

ecowarrior

Hi Tom Well there is all but no information on CCT's in the UK so I am entirely in your hands. Is your comment suggesting normal reverse returns from the two boilers into one pair of CCT would be better? The 2 boilers will be cascading to utilize the lowest turn down ratio on just one boiler for the smaller loads? (Turn down ratio is the ratio between high modulation & lowest modulation just in case u use different phrases. I still don't know what a furnace is lol)

Mark Eatherton

You could save some joints by only having one pair of take off tees from the main. You don't need separate tees for each boiler or load. In fact you could have one set of tees for ALL inputs and one set of tees for ALL outputs.

Although primary/secondary piping works great, there are a bunch of unknown recommendations as it pertains to straight pipe lengths before and after tee's that rarely get followed and create ghost flow conditions that take away from the base efficiency of this design. Check valves on each boiler circuit are mandatory regardless of how its piped to prevent reverse flow in the off cycle. The same applies to pumped outputs.

I once told John Siegenthaler that Low Loss headers were for people who didn't know how to properly do P/S piping. I have since changed my opinion in that some of the LLH's can do triple duty (separation, dirt removal, air removal) and hence are quite worth the investment in that they save material and labor that more than covers their initial cost.

By the way, Caleffi is a very large Italian concern with American representation and interests. A great company to work with.

Welcome to The Wall, the worlds greatest hydronic industry information resource.

ME

SWEI

Closely spaced tees implies adjacent supply and return branches, so cold next to hot for each boiler, and (as Mark alluded to above) space between the two sets. Pretty sure this diagram actually came from Mark:

Rich_49

Tom,

Maybe you could draw what you are recommending .

SWEI

You can also build your own LLH, which would work well for the physical layout shown. The vertical pipe should be 3x the smallest branch size.

ecowarrior

The Low Los Header would be the normal British way. Its the Close Coupled T's that u chaps use that have intrigued me. LLH can be clunky & clumsy to pipe so I have been looking at one vertical pipe with the CCT pulled one side & the 2 pairs of F&R pulled the other. Air vent on the top - drain off on the bottom - hey presto! This vertical pipe will be well under a meter (3feet) and can have the CCT at 90 deg to the load F&R so I can pipe it right in a corner? (I think!!)

SWEI

You can have multiple input and output ports on a hydro separator. To do this, remove the closely spaced tees, triple the size of the vertical riser pipe, put all the hots on top and all the colds on the bottom. You can rotate tees as needed to fit it in a corner.

ecowarrior

OK - I am a bit lost with the drawing (Dim Brit Syndrome)
lets say the common pipe is 2" so from the centre of the top pair of T's my pump must be 20" away, and a further 8" the downstream side of the pump before the second pair of Ts can enter from the second boiler? Also the shunt pumps (from boiler to common pipework) the T's on the common pipe? must be 20" from the common pipe?
Also 16" from theCCT's to the second (load) T?
My big question is - where has the third pump come from & what does it do? (My shunt pumps are integral in the boiler)

I think I have got this completely wrong?

Tom_133

Ecowarrior

If you remove that pump in between the two closely spaced tees you would have what I suggested. Though as Mark E suggested it can be done even better.

Rich_49

Tom ,

Are you suggesting that if he moved the circ that would be alright ?
I find that curious as water that has been heated by the lower boiler would then be pulled in to the higher boiler to be heated . I would bet that this is certainly not what ME meant .

Paul48

http://www.htproducts.com/literature/EliteFT-Brochure.pdf
Nice drawing of what you want to do here.

ecowarrior

SWEI said:

Closely spaced tees implies adjacent supply and return branches, so cold next to hot for each boiler, and (as Mark alluded to above) space between the two sets. Pretty sure this diagram actually came from Mark:

If the 2 boilers were reverse returned - only one flow & return so only 1 pair CCT with all the flow entering one point.. having them separate (2 x CCT) and having them quite apart doesnt seem logical? Where does one find the math for this?


I note your LLH have the flows & returns oposite each other? In the UK we use a variety of staggered outputs some I'm sure from old wives tales but the '4x12 rule' is common. Primarys are 12x the tappings apart the secondaries 4x tapping apart. Header diam is aprox 3x the tapping.
No 2 manufactures have the same design for the same Kw (apart from tapping size & header diameter) but they all seem to work.

SWEI

ecowarrior said:

lets say the common pipe is 2"

That should work if all of the inlets and outlets are 1/2" or 3/4".

so from the centre of the top pair of T's

No more pairs of tees. Cram all the red pipes to the top of the column and all the blue pipes to the bottom of the drawing. Better yet, get a tee drill and make them even closer, with whatever angles you need them at.

my pump must be 20" away

No pump in the separator, just a "wide spot in the road" where everything slows waaaay down. See this starting on p.32.

ecowarrior

lets say the common pipe is 2"

This was a nominal size for ease of maths

No more pairs of tees.

Looks like we are moving away from CCT towards LLH?

Cram all the red pipes to the top of the column and all the blue pipes to the bottom of the drawing.

Would it no be easier to link the boiler primaries, pipe up in reverse return & just have one inlet/outlet from the boiler

Better yet, get a tee drill and make them even closer, with whatever angles you need them at.

Birds Eye View

No pump in the separator,

Thank heavens - I thought I was loosing it!

just a "wide spot in the road" where everything slows waaaay down.

Obviously note to scale - but are we not leaving CCT and designing a LLH? the 12x primary is how u would rule of thumb design in the UK with 3x Diamiter of primary as the header.

ecowarrior

Perhaps this is more what you meant? I have added a LLH that I recently fitted.

Forget the 12x Primary - forgot to delete it!

Tom_133

@Rich you are correct, if those two boilers in the pic run at the same time you will have issues. I am typically piping that way for two boilers that won't run at the same time, like with a wood boiler and a gas back up. In this scenario the way Mark E suggested would be best or even the HTP design looked good.

Thanks for the correction.

SWEI

You're getting warmer. Push all the blue tees as close together as you can. Do the same with the red tees. I'm not sure what the requirements for space between the two "stacks" of tees, but since your trunk is 3x or more the diameter of the branches, I know it's a lot less than 12x. Might have to build one or two and test if you're using off the shelf tees. Can you get double branch tees there?

We do this using Aquatherm pipe. The fusion outlets allow us to drill wherever we want. If this is a closed system, you could do it in steel using Weld-O-Lets or half nipples.