LOW LOSS HEADER, a guide to when, where and how on the installation of a low loss header.

[@andrewmillwardwatford9410]

You are confused about head. This is not the important factor. Mass flow rate is the focus.

[@davidb2464]

You mentioned upsizing pipework might negate the need for a low loss header, so for instance, if I upsize pipe to 28mm on the flow, then 22mm running to rads, then 15mm tails to individual rads, do I have to mirror the flow in the return, ie, using 28mm pipework, or is it more efficient (also to help when balancing rads higher up)to restrict the return?? Also, when trying to make an old heat only boiler system get water to higher up rads, could I just replace a length of 22mm pipe with some 28mm pipe? If so what would be the minimum length of 28mm pipe?

[@nemanjagradinac5419]

No there literally isn't any better videos out there explaining this in as much detail. Brilliant information. Cheers mate

[@joetyson6223]

Hi Loved the video, I come back to it a lot. Would a low loss header. Improve the efficiency of an electric boiler?

[@ianferguson4846]

everydays a school day, have you heard of the Dursley baker neutraliser ?

[@chohanchohan8208]

Omg I always wanted to know where and how to use these...BIG THANKS Del

[@andyjones7836]

Nice tutorial Derek!! I noticed you refitted the filling loop the right way around too 👍👍 Although these should be disconnected, but who does that 😉

[@bluenapalm123]

Great vid thanks. I've 2x 30kW gas boilers LLH 4 zones - each with circulation pump and zone valves I'm researching as to why when two zones are running, that the system pressure hits 3 bars and PRV (if that's correct name) lets off water outside. System starts cold at 1 bar. Expansion vessel still has air coming out when I very briefly let some air out. All pumps on lowest setting (26l/min) Boilers I believe are 12.4L/min each (24.8 l/min total)

[@michaelrose5040]

Hi Derek Just passed my first ACS today massive thanks to you for taking the time and effort with your videos that have been crucial to me passing.

[@tomkatgastraining]

Well done welcome to the world of gas 👍🏻

[@mgbroadsterJ]

Does it need a bypass where the pumps are fitted ? or does the motorised valve open first .

[@nickadams5212]

Nice video Derek very well explained as usual 👍

[@Loopyengineeringco]

Is a LLH also used when retrofitting UFH into a system with just a large primary system with radiators, coming off a heat pump? Or is it just to separate the boiler/heatpump from the rest of the system?

[@brendanfisher2528]

How do you know what size LLH to fit?

[@jockster5525]

Awesome thanks very helpful indeed mate

[@duncanmacdonald9584]

install Low Loss Header, but because of lack of space to install LLH vertical, what distance from the boiler can I position the LLH, the boiler would operate normally ground floor, install LLH on second floor use 15/60 pump same as boiler instead of 25/80 pump to circulate flow to second floor and loft area

[@martynlewis9020]

I watched another YT plumbing channel trying to describe the principle of a low loss header, but HOLD TIGHT! This is a better video. Thanks.

[@mj0n4id36]

I was once shadowing and there was a low loss header being installed but to be honest I didn’t have a clue as to why it was installed. Lol. Now having watched this video it makes more sense. Very informative and what seems to be complex at first you have made it easy to understand with your explanations and drawings. When you mentioned about the filling loop not being installed correctly, sorry, I didn’t notice what was wrong..?? Thanks Derek 👍🏻. Asian Jon. Training.

[@tomkatgastraining]

The isolation and non return valve were the wrong way around

[@mj0n4id36]

@@tomkatgastraining Ahh ok.. thanks!

[@mgbroadsterJ]

Or multiple pumps .

[@stephenpauldowle9777]

Would you install auto bypass on your pipework going to your rads eg 3x valves on 3 x circuits. Many thanks

[@eddiestafford3313]

Great information....well presented...thank you!!

[@hvacdesignsolutions]

If the boiler pump has enough available head, use a common PHEX, instead of a LLH.

[@rodsilva80]

Thank you

[@rayc1503]

I'm sure enough engineers think a low loss header will solve all their woes when it comes to hydraulic separation. It's the total mass flow rate which needs to be calculated along with the delta T between return and flow. I've seen LLH installed in applications which don't require them. Which is an unnecessary cost to the customer. Infact some are way over sized. System design and calculations are key. It's not all about slapping a boiler and Rads on the walls and hoping for the best. Some engineers carry a misconception that LLH will solve the issues of a poorly out laid system. Not always the case. With undersized pipework on a large system a LLH is pointless.

[@TheMarg28]

Hi Derek, would you put a pump on the dhw coil or just T it in to the flow before the LLH so it relied on the boiler pump ? Im doing a small comercial system and wandered what was best. Thanks mate

[@1000Mikey]

I've seen a dedicated dirt scrubber on LLH before. Would you use commissioning valves to balance this on a smaller system like this? would you need them?

[@6969allgood]

I did not see any bye pass valves after the new pumps before zone valves ?

[@tomkatgastraining]

The bypass is only needed if you have pump over run or the pumps run after the valve shuts so the pump isn’t pumping against a stopped end. Because the low loss header is open all the time they are not need for the boiler pump over run also.

[@allandewar]

Great vid mate . Love your enthusiasm and your knowledge is very much appreciated

[@mwong000]

I heard Derek say "when" we need to use LLH, but not "why". As I am replacing my 40 year old cast iron boiler and designing a new system around a single condensing boiler, 8 zone system, I fail to see ANY reason to use it whatsoever. As a matter of fact, I fail to see in a single boiler system with single Delta T modulated circulatory and where low energy usage is the primary concern, why anyone would both to complicate things with a Low Loss header. After this video, I still don't understand "why". I only understand "why not".

[@tomkatgastraining]

I think I explained why and why not so if you skipped through the video you probably missed it

[@Anthony-dh3ty]

Why split your home into 8 zones unless you have a mansion. The less zones the more efficiency you get on a low temp system. If you're having multiple external pumps you will need seperation with close coupled tee's or LLH

[@mwong000]

@@Anthony-dh3ty Thanks Anthony. I have a 4700sf house with lots of high ceilings and rooms that are open to each other. Plus 2000 sf of windows. I bought the house in 2016 and it came a cast iron boiler with 8 zones. But Anthony, you are absolutely right, the zones reduce the heat dissipation and therefore it was a stupid design. Lots of energy was lost up the flue. Therefore, I opened all of them up, and added Power Off Delay relays to the circulation pumps (one for the underfloor heating, and one for the baseboards), thereby pulling as much heat as possible from the cast iron heat exchanger and sending it to the living areas. Since heat los is proportional to Delta T, I think Ohms Law (Current = Voltage/Resistance). is applicable to heat transfer as well as electricity. I would say (Heat Transfer = Delta T/ Heat Resistance). In other other words, heat goes up the chimney AND it goes into the baseboards. How fast it is transfered is inversely proportional to on the heat resistance. The faster it goes into the baseboards (by opening all of them up), the less goes up the chimney. Ever since I made this changes, my heat bill dropped by 30% year to year (326Terms to 212 Therms in February). My house is much more comfortable at lower temps - my body is not radiating heat to cold objects in adjacent rooms. There is another advantage. In December, I lowered my temperatures so much that one of the pipes froze. Even though the basement was 46F, the non moving water temp was lower. I was lucky it was not a hard freeze, so it did not burst. Now that I have my pumps running nearly constantly, the pipes will not never freeze, since the water temperature never drops below my basement set temperature of 46F. By the way, I have a TACO 007 which pulls ½ amp (60watts), so my electric cost is $0.15 /day. By the way, I still don't understand why a person with a single boiler needs a LLH, instead of just leaving the pumps running. As long as the pump are running, there is no thermal shock to the heat exchanger. Besides, an efficient system exists when the return water temperature is low. A LLH increase return water temp, reducing efficiency. Whereas a constantly running pump guarantees low return temperatures.

[@stuartparks5558]

Thank you, Derik, for another great video clears up a lot of questions 👍

[@markhoward5780]

If you have pumps pulling 50 litres i guess you have to have a pump on the boiler that can cope with this ie 55 litres upwards , thanks

[@halemotors4084]

Interesting stuff! One question? If the boiler produces 30ltrs flow how can you have 50litres draw on the other side? Thank you

[@tomkatgastraining]

The other pumps

[@matt635d8]

Buffer tank is the best way to do hydraulic separation .

[@noelburke6224]

No need for low loss header when you size the pipe work properly, you can use a system links

[@paulrossiter9567]

Brilliant fool proof learning about how a LLH works. You nail it to the wall in layman’s terms 👏👏👏👏👏 Very interesting ...thankyou 👍

[@duncanmacdonald9584]

My dilemma is how to get enough flow to the loft area in an old Victorian house. (12ft high ceilings) An 8m pump will do the trick as the boiler 42kw cdi 2 zone S. plan, was positioned incorrectly for the 15/60 pump to deliver enough flow to heat the radiators on a part of second floor and loft. (1) If I can get a 8m pump head only replacement to fit the boiler casing. (would this work on the boiler as it is only affecting flow) (2) reposition boiler higher to compensate for poor flow rate. (3) install Low Loss Header, but because of lack of space to install LLH vertical, what distance from the boiler can I position the LLH, the boiler would operate normally ground floor, install LLH on second floor use 15/60 pump instead of 25/80 pump to circulate flow to second floor and loft area. I have seen LLH fitted horizontally yet you say not advisable. Use a Blanking plate on boiler pump then install an external 25/80 pump, without the need for a LLH . your thoughts would be helpful thanks

[@plumberdan5720]

Sounds like a homunculus valve is needed in your situation to aid flow to the loft.

[@martynjukes482]

Been fitting these for years commercially but like most pipe fitters I have never really broke down the mechanics of them. Thanks for breaking this down mate.

[@hdhanji8006]

Hydronics, right up my street :) Top intro to LLHs and the pitfalls to avoid. Great work 👍

[@MSKChess]

fascinating and pretty complicated dynamics.

[@senna4281]

Question, can you add a hot water tank to a combination boiler and have the combination boiler heat the tank. Plus what temperature would you recommend setting the heating system at 50c 55c 60c etc. Andy I have just had a visseman 35kw 111 fitted

[@tomkatgastraining]

Yes you can and the water in the cylinder will need to be heated over 55 degrees centigrade to kill legionella but why would you use a combi what about heat only or system

[@KrisFarquharPlumbingnHeating]

Hi Derek, been watching your videos and your really good at explaining the methods in all aspects of your teaching, keep up the good work, mondays and wednesdays so lets got on with it, brilliant Derek,

[@mohammednadeem7274]

Great video Derek once again amazing. Well explained like a Pro.. 😀👍

[@keithcave4505]

Could have explained that in 2 minutes

[@peterbeck493]

Love this one you have made it make sense Derek. Always learning,you know your stuff keep up the great vids.

[@anonymous.youtuber]

Nice how you explain this in a way it can be understood. 👍

[@Bradwellify]

Thomas Bradwell Thanks Derek

[@saidhissoufi277]

Always delivering with passion. Well done

[@anthonybennett6008]

Pump then zone valve or zone valve first?? Every where I see it is pump first but you had opposite??

[@tomkatgastraining]

I do it that way so as the valve is opening it doesn’t get the full force of the pump but it makes no odds which way you do it I guess I am still used to commercial work as that’s the way we did it.

[@mohammednadeem7274]

Might need one in my house, after watching this.. 😂😂😂

[@noelburke6224]

Mag filter is to protect the whole system

[@Skeletoncrew46and2]

Nicely explained and simplified. Some videos on the youtube can make them seem more complicated than they really need to be.

[@user-vs5fi2vy3h]

Brilliant great knowledge

[@andrewthomas332]

awesome video Tomkat Gas Training

[@manjsingh6500]

Enjoyed. Great explanation

[@me92994]

Hi where we connect the second pump in that case Derek

[@aaronjoyce1980]

Just watched Aaron trainee 👍

[@davidkneale7455]

Is this not just a modern version of the dunsley neutralizer from the 70s?

[@tomkatgastraining]

Yeh

[@gregginnever8497]

Evening Derek, Could you put a non return valve/check valve to stop reverse circulation?

[@tomkatgastraining]

You would still draw the cooler water coming back on the return

[@samchappell233]

Great information 👍👍

[@jethrohealy3277]

Hi Derek, thanks for the info. I have worked on several systems with LLH’s but have never installed one. I was wondering if you installed an automatic bypass on each flow after each individual pump? The boiler will still circulate through the LLH during pump overrun but when the zone valves are all closed it makes sense to me to have an automatic bypass on each flow? Thanks, Jethro

[@tomkatgastraining]

It’s not a bad idea but we wire it so the secondary pumps don’t come on until the valve opens and the pump stops before the valve shuts so no need really for auto bypass because no pump overrun .

[@jethrohealy3277]

@@tomkatgastraining thanks Derek, you should be ignoring this and relaxing until tomorrow. Thanks for the reply. Makes sense.

[@leeevans369]

Brilliant well explained thank you

[@secondchance4498]

chris taylor

[@abooli2]

Best video Do you conduct training courses aswell

[@tomkatgastraining]

Not for low loss headers

[@SuperWayneyb]

👍🤓👍

[@leaturk11]

Why could you not use a plate heat exchanger in place of the low loss header?

[@tomkatgastraining]

I would only use a plate if I wanted to keep the primary and secondary system separate say if you wanted the boiler on sealed and the heating open vented

[@raul835]

Another excellent video..

[@john-paulcox918]

Really interesting vid .

[@lazylady81]

When fitting exp vessel, what if boiler has no exp vessel like a Keston for example what side should you put it on, or does it matter?

[@tomkatgastraining]

As close to the boiler as practical on the return pipe is always best

[@lazylady81]

@@tomkatgastraining Thanks mate

[@nazirmohammed7285]

Excellent video 5*

[@M20DAN]

Tomkat👍🏻

[@suheilhanna873]

Very informative

[@1Monaghan]

Have you got any videos on flushing / power flushing and how it’s done ?

[@tomkatgastraining]

There is a video on magnetic filters and how to use a magnacleanse

[@tomkatgastraining]

kzbin.info/www/bejne/aoPUgmhvmadnoJI Here is the link 👍🏻

[@1Monaghan]

@@tomkatgastraining Thanks!

[@andrewmillwardwatford9410]

Your videos are very good but you make a few mistakes on this subject.

[@tomkatgastraining]

We all make mistakes 😁

[@andrewmillwardwatford9410]

@@tomkatgastraining sorry Derek I love your videos and direct people to your utube channel. Ypur knowledge is fantastic and you are a great teacher. This subject though is very misunderstood and I get continual questions from confused engineers on this topic.

[@tomkatgastraining]

@@andrewmillwardwatford9410 as I said in my video there are a lot of guys like you on KZbin who can explain this subject a lot better than I ever could and that’s why I called it an introduction yes I could have gone on about mass flow rates but most guys who watch my videos don’t care about that they just want to know the basics at the beginning and then work their way into it so I just try and keep them interested because as soon as you mention maths they turn off. You could also argue a little knowledge is a dangerous thing but in this situation it’s just an introduction. I appreciate your interest in my video it means a lot and hopefully I haven’t offended you to much with my mistakes. Cheers for watching and your comment 👍🏻

[@andrewmillwardwatford9410]

Thanks for your reply.

[@jonnyf9088]

Do system boilers have the internal pump on the return?

[@tomkatgastraining]

Yes they do

[@jonnyf9088]

@@tomkatgastraining ok thank you. If you were replacing a system boiler for a heating only boiler with separate pump and expansion, would you put the pump on the return or the flow? Thanks

[@tomkatgastraining]

@@jonnyf9088 pumps go on the flow on heat only boilers

[@jonnyf9088]

@@tomkatgastraining thanks - how come they are different?

[@tomkatgastraining]

@@jonnyf9088on combi boilers the pump has to go on the return because of the diverter valves and a system boiler is just a combi. On the heat only it goes on the flow because of the controls.

[@asif530]

Hi Derek great video. I have a question. Is it possible to do hydrolic seperation using a plate heat exchanger heating the water in the secondary circuit and have the secondary circuit with a pump with a higher head value if the boiler pump is not sufficient. Although I assume this way on the secondary circuit you will need a filling loop and prv and expansion vessel?

[@tomkatgastraining]

A plate heat exchanger completely separates the two systems you can even have one side vented and one side sealed

[@mixer7586]

I think the system dirt would rule out the plate heat exchanger on larger commercial installations. ?

[@tomkatgastraining]

@@mixer7586 fitted plate heat exchanger in commercial jobs and had no problems

[@mixer7586]

@@tomkatgastraining then why the need for low loss headers if total hydraulic separation can be achieved by plate heat exchangers? Cost?

[@mixer7586]

Flow rates not good enough through plate heat exchangers??