This is a first rate video Andrew, its technical but easy to understand, thanks for taking the time to put it up its much appreciated, I've always wanted to have a greater understanding of low loss headers but it's been hard to find good information until now.
Fantastic video Andrew. You’ve said .3 m/s in LLH, .5 in distribution header. What would you want in the primary header if you were cascading 2 or more boilers, to ensure the load was split evenly between the two boilers?
Sam Morrison I would assume .5ms is ok but I have no source for that it's a guess only based on the distribution header. Different sources give different velocities and those I've stated are fro. Good sources but ones I've chosen to adopt.
Very interesting Andrew, I have a question though. With the 3 circuits all set up on the secondary side, pumping & flowing, if one pump is satisfied & shuts down, doesn’t this affect the flow rates of the other two circuits? Thanks, Rus.
The low loss header allows each circuit to act with no influence on the other/s. So if two pumps turned off the remaining circuit would draw the exact same volume of water. The flow in the boiler would also remain the same. The only change will be the boiler modulating to a lower power out put. A lower power out put but the same temperature.
Great video, I have a question your first drawing why can you not just alternate the connections on the secondary side; If you number the connections from top to bottom 1 to 6, so you use flow 1 and return 4 for circuit one, flow 2 and return 5 for circuit two, flow 3 and return 6, would this not counter balance the middle circuit staying in static loop. Would be very interested to see your opinion.
Sorry I just see your comment. The order wouldn't matter but flow rates would. You could arrange flow rates in an order to work. My explanation is about how I see them not working in the field. The second option saves the need for careful design.
B1cam what do you mean by "see" you can measure and calculate. Dt across circuits and a gas rate will by calculation give flow rates and energy distribution.
Hi mate been watching your channel your knowledge I have a strange 1 for you I have just fitted a ideal evomax 150 kW with single low loss headed primary pump on the return and secondary on flows one for a ahu heater coil and the other a hot water cylinder the flow would only go down the primary flow to header over heat boiler and cut out if I turn secondary pumps off it will flow round header and back to boiler turn them on the secondary flow would only get up to about 35c and would over heat the primary flow but primary return cold I have since removed header and the system works fine but can't figure out why it did not work as have used this set up before on evomax 60kw and all worked fine
Hi Andrew, extremely informative video. I have a question on a site we currently have a horizontal LLH which have primary pumps feeding it, we then have 3 outputs feeding AHU's, radiators and UFH. My question is contractors have recently install a new section to the LLH but they've tapped off each end of the LLH would that have a impact to the balancing of the existing LLH
Hi Andrew can I pick your brains for a minute if I have 2 x 60 kw boilers feeding onto a low loss header what size should my primary pumps be for the 2 boilers thanks as been told a 15/50 will be fine but seems to small to me
Hi. A 15 50 will likely be ok if feeding a low loss header. You should look at the head loss graph for the boiler and the pump performance graph for the pump. If the pump can move the or a higher flow rate required at the headloss of the heat exchanger at maximum flow it is suitable. Join me on the forum for more information or we can talk on messenger or whatsapp
@@andrewmillwardwatford9410 Hi Andrew. I've got that CIBSE domestic heating design guide and it's got nowhere near the amount of detail or mathematics you've used. There's nothing more than a small paragraph followed by a few sentences. I'm desperately trying to find more technical information on LLH's. I've got CIBSE AM14 also but that doesn't have too much in it either. Are you sure there isn't another design guide you've got? Any help would be great. Thanks. Tom.
@@andrewmillwardwatford9410 struggling with the maths behind it all, I know you explained how to do the formula but I'm terrible at maths. Love your videos BTW your a very very knowledgeable engineer!
Home radiator heat not bothered how fast the water flows,in, out T1 T2 hotter coming out than going in how is this possible Ti 37c. T2 40c no other means of heating.
I see this a long time ago. I reduced pump.speed and it was normal again. I never understood why or how. It was a very strange pump that had a lever on the rear. Maybe the lever allowed to reverse the pump, but I don't understand why that would be. I assume the lever was a flow control but I think it must have been reversing.
Excellent as usual. Very generous of you to post all of these.
Thank Andrew; great not just to see a explanation how the low loss header works but also pointers at how to confirm the maths behind it.
facebook.com/groups/1283670701667577/
This is a first rate video Andrew, its technical but easy to understand, thanks for taking the time to put it up its much appreciated, I've always wanted to have a greater understanding of low loss headers but it's been hard to find good information until now.
facebook.com/groups/1283670701667577/
Suddenly, it all makes sense.
Thank you.
And thanks for telling us what low loss means, no one else bothers to say that.
Well done.
facebook.com/groups/1283670701667577/
facebook.com/groups/1283670701667577/
Brilliant explanation!
Thanks very much. Have been looking for a explanation that makes sense. Cheers.
You are welcome!
Thank you Andrew very informative
Robert Charzewski thank you
Very well explained.👍 Thank you.
Informative and to the point . Thanks for you efforts.
facebook.com/groups/1283670701667577/
Fantastic video Andrew. You’ve said .3 m/s in LLH, .5 in distribution header. What would you want in the primary header if you were cascading 2 or more boilers, to ensure the load was split evenly between the two boilers?
Sam Morrison I would assume .5ms is ok but I have no source for that it's a guess only based on the distribution header. Different sources give different velocities and those I've stated are fro. Good sources but ones I've chosen to adopt.
facebook.com/groups/1283670701667577/
Very interesting Andrew, I have a question though.
With the 3 circuits all set up on the secondary side, pumping & flowing, if one pump is satisfied & shuts down, doesn’t this affect the flow rates of the other two circuits? Thanks, Rus.
The low loss header allows each circuit to act with no influence on the other/s. So if two pumps turned off the remaining circuit would draw the exact same volume of water. The flow in the boiler would also remain the same. The only change will be the boiler modulating to a lower power out put. A lower power out put but the same temperature.
Really love your videos Andrew ! Joined Facebook so I can join your forum but having trouble finding you 🙈 I am just search Andrew Millward..
Heating Nerd search for
The continual heating design learning event on line.
Great video, I have a question your first drawing why can you not just alternate the connections on the secondary side; If you number the connections from top to bottom 1 to 6, so you use flow 1 and return 4 for circuit one, flow 2 and return 5 for circuit two, flow 3 and return 6, would this not counter balance the middle circuit staying in static loop. Would be very interested to see your opinion.
Sorry I just see your comment. The order wouldn't matter but flow rates would. You could arrange flow rates in an order to work. My explanation is about how I see them not working in the field. The second option saves the need for careful design.
thanks for the video. It would be good to see impact distribution of heat during the flow distribution ?
B1cam what do you mean by "see" you can measure and calculate. Dt across circuits and a gas rate will by calculation give flow rates and energy distribution.
Hi, i mean the water flow/rtn temperature, the impact that the LLH has on temp, due to different flow rates and circuits.
B1cam yes. Measuring Dt and a gas rate will allow calculation of all energy paths.
facebook.com/groups/1283670701667577/
Hi mate been watching your channel your knowledge I have a strange 1 for you I have just fitted a ideal evomax 150 kW with single low loss headed primary pump on the return and secondary on flows one for a ahu heater coil and the other a hot water cylinder the flow would only go down the primary flow to header over heat boiler and cut out if I turn secondary pumps off it will flow round header and back to boiler turn them on the secondary flow would only get up to about 35c and would over heat the primary flow but primary return cold I have since removed header and the system works fine but can't figure out why it did not work as have used this set up before on evomax 60kw and all worked fine
We could do a video call from your job. Need to see it.
Hi Andrew, extremely informative video. I have a question on a site we currently have a horizontal LLH which have primary pumps feeding it, we then have 3 outputs feeding AHU's, radiators and UFH. My question is contractors have recently install a new section to the LLH but they've tapped off each end of the LLH would that have a impact to the balancing of the existing LLH
It could be a problem if not correctly laid out. Contact me with some picture
@@andrewmillwardwatford9410 thanks Andrew will do, what is the best way to send them I don't think you can do it on RUclips comments.
@@jamesmcleod9841 google my name and find my company
so inside the low loss header unit there are no baffles or anything? I havent worked with these before, very interesting though.
Some llh have baffles, most do not.
Hi Andrew can I pick your brains for a minute if I have 2 x 60 kw boilers feeding onto a low loss header what size should my primary pumps be for the 2 boilers thanks as been told a 15/50 will be fine but seems to small to me
Hi. A 15 50 will likely be ok if feeding a low loss header. You should look at the head loss graph for the boiler and the pump performance graph for the pump. If the pump can move the or a higher flow rate required at the headloss of the heat exchanger at maximum flow it is suitable. Join me on the forum for more information or we can talk on messenger or whatsapp
Hi Andrew,
What was the book you mentioned in this article?
Cheers
Jase..
Domestic heating design book
@@andrewmillwardwatford9410 Hi Andrew. I've got that CIBSE domestic heating design guide and it's got nowhere near the amount of detail or mathematics you've used. There's nothing more than a small paragraph followed by a few sentences. I'm desperately trying to find more technical information on LLH's. I've got CIBSE AM14 also but that doesn't have too much in it either. Are you sure there isn't another design guide you've got? Any help would be great. Thanks. Tom.
@@tommojenko what information do you need ?
The callefi series may help you.
Could you do an example of that formula please? Struggling with the square root.
What is the issue your having ?
@@andrewmillwardwatford9410 struggling with the maths behind it all, I know you explained how to do the formula but I'm terrible at maths. Love your videos BTW your a very very knowledgeable engineer!
@@plumberdan5720 feel free to call me. I will explain
@@andrewmillwardwatford9410 how do I contact you?
@@plumberdan5720 search for me on face book
What is the unit of ID in the equation?? mm or cm
Thank you.
mm
Home radiator heat not bothered how fast the water flows,in, out T1 T2 hotter coming out than going in how is this possible Ti 37c. T2 40c no other means of heating.
I see this a long time ago. I reduced pump.speed and it was normal again. I never understood why or how. It was a very strange pump that had a lever on the rear. Maybe the lever allowed to reverse the pump, but I don't understand why that would be. I assume the lever was a flow control but I think it must have been reversing.
I don't really understand your question but you are welcome to call me