Great bit of kit in the right situation, we fit lots of these in assisted living flats. Work fantastically when set up correctly. Only down side is when the plant room boiler fails nobody has any heat or hot water.
I’m so grateful for this video. Thank you so much Alan and David. I’ve just started a new job and there’s around 60 hiu’s Incredibly informative and so helpful. 👍👍👍
Perfect explanation by both of you... i found this extremely helpful as a council leaseholder to understand the new unit I have been offered. Thanks so much!
Interesting that Allen, its not something i just didn't understand, I didn't even know they existed, but but pretty cler when explained by you, cheers :)
Nice unit, He missed Chp as a heat and power source,which combined with a heat store is a great option, perhaps Vokera don't install them. Have worked on similar systems at hotels in Southampton using the City Geothermal system. 10 inch supply and return on those!
My daughter bought a flat in London with this type of heating four years ago,nightmare constantly having no heating or hot water ,plant room failures engineers not able to balance flow and returns over the different floors, if you had heat somebody else didn’t.she lost so much time from work over giving access to engineers she sold the flat. Plus b g had the contract for energy and the tariffs were expensive.
Although the video is only about the technical aspects of how HIUs work, I fully sympathise with your comment. District and Communal Heating schemes (You will be using one of these schemes if you have a HIU) are legally unregulated and residents are obliged to accept the monopoly that the heat provider is. So not only do end users have to accept the heat provider and are prohibited from exercising the freedom to switch suppliers, like a customer who has a system that heats their home's water (majority of UK), but if the heat provider charges an excessive amount or provides a bad service, the resident has no recourse as the industry is unregulated. The regulator, Ofgem, has no authority to get involved. This is a very important consideration when one is considering moving to somewhere that has a heat network. The heat provider can provide terrible service, charge you double what you would pay per kWh if you could choose your own supplier, and there is absolutely nothing you can do about it, other than quit the home, which is what your daughter sadly concluded. It is shocking that the industry is unregulated.
CHP is a option. You usually find them on really big buildings like , gym's Windsor Castle and Buck Palace . I prefer the cascade multiple boilers just in case one goes down. If the CHP goes down ya buggered UNLESS you have a cascade with CHP as backup. I kind of like this idea but if you are running a plantroom with multiple rooms then all you need is a local stat and the DHW on a return system. I think it might be a expense you don't really need.for example I do some work on uni students accommodation. All run off the plantrooms and each apartment has its own stat. What's your thoughts?
Hey Allen, great video mate. One question: If the last two radiators in this system are cold, but the second to last rad is hot at the TRV but a lot colder at the Lock shield valve - What would you suggest to do with the balancing? And second question if you don't mind, can I confirm that the Lock shield of the last rad in the line would be the 'most open valve'? I appreciate any advice you can give me. J
Interesting. As long as the overall execution does not cheap out, by specifying inappropriate valves which would make balancing between ‘apartments’ impossible and not providing redundancy (and automatic changeover) both in primary heat sources and circulating pumps
Could I ask a question about Allen’s video,he mentioned the plate exchangers are always hot and ready, how is this achieved without being charged/metered for it ?
At the beginning of the video you stated there is no plate heat exchanger inside the unit. After taking the cover off there was a primary and secondary plate o.O
Hi, hoping you could guide me in the right direction. I have the exact same unit in my flat. I can feel the hot water coming into the unit but when I turn the taps on the water is hot for 5 seconds and then freezing cold. What could I do to have this resolved ? Flat is only 2 years old
I have a question, where I work, the apartments residents mostly complain about their DHW, as in no hot water on most occasions, we have HIUs, is this a plantroom related problem?
I have an Evinox MTP50-10 which is opening and closing the HE control valve soon after the circulation pump kicks in and the pump keeps functioning. I'm reckoning it's an issue with the temperature sensors but I can't find the specs on them (S3, S4 and S5). Do you know if they're type K thermocouples or thermistors and what type? (2 of them look like thermistors and one looks like a thermocouple. I don't think they're original parts)
Hi I have one of those in my flat and want to move a radiator from its current place to somewhere along the wall. The question i have is does the person coming in have to bleed the whole system and fill it back up ? I have a feeling bleeding the system does not have to be done with a normal boiler but don't know if this is different or he is just saying this to hike up price?
got a problem with mine, the down stairs sink hot tap is working fine and getting really hot water but the up stairs sink hot water has been fluctuating and now hardly getting any hot water. what could it be .
hi, ever come across the situation where occassionally need to turn the heating out for hot water to come out of the taps? i.e. tap is turned to out but only cold water coming out of the tap until the heating is switched out which in turns heats up the water for it to come out of the tap hot?
Any idea why the DHW (Domestic Hot Water?) only activates when the heating room thermostat is either furred down past current room temperature or set to OFF?
@@johnburns4017 yes. It might be an electrical actuator with controls. But yes, it will bypass when the dhw is up to temperature. It can be any heat source. In Aberdeen, lots of the council buildings, blocks of flats, all get heat via plate heat exchangers. There is a loop around the city that has various boiler plants that feed into the loop, then these feed into plates, instead of boilers. District heating.
@@Brijoolz I doubt electrical as these units tend to have as little elecrical as possible in them. Quality mechanical controls last and last - but cost. Look at the quality of the electrical controls on low to mid priced combis. Even on cars, most of the breakdowns are due to electrical failures - ask the AA.
If an apartment has hot water in kitchen, second bathroom, but in end main bathroom that shower starts warm then loses heat. Is that likely a HIU issue or thermostatic valve issue? (Sink in that shower works well)
District heating is becoming very big in the UK. I maintain over 2k properties in the Glasgow area. A lot of folk are still getting used to them but I think they are a good efficient set up. The company I work for specialises in biomass so the schemes primary heat source is biomass. A gas/oil back up is essential in case of primary boiler failure. Of course some units are better than others, as with gas boilers. Do you have fault finding videos that I could let our apprentices watch. A really informative video, thank you 👍🏻
@@Liusila Gosh I thought I was the only one in here think this. It's absolutely diabolical to live with. Never get enough pressure in the Water Heating System. Unvented cylinder much more effective with the premise of having a backup of a heating element just in case.
We have 12 of these installed in a new build block of flats for the last four years, as a facilities manager the system has been a nightmare. The two cascading 100kw boilers on the low lost head system constantly heat the hot water rail from the plant room to 80 degrees. The hot water rail is very well insulated but still cause massive secondary heating of the flats in summer and the whole building. It is also not helped as the flats are modern, well insulation and pressure tested to pass the energy performance certificate, there's no were for the heat to go. This has resulted in flats being above 30 degrees, and elderly clients passing out as result of the flats not being able to lose heat. The whole complex is constantly warm posing a problem to delivering cold water that is below 21 degrees as by the nature of the system the cold water is bought so close to the interchanged units and uses cavities next to the mega hot water rail pipes. And then who pays for the hot water rail? Its the landlord 24hrs a day 365 days a year, just so a tap can delver hot water 20 seconds faster than a combi. The taking of kilojoules readings and billing is admin heavy and takes up a stupid amount of time. So do buy the £10k software to try and save some time but it also important as the kilojoules meters batteries go flat and are not cheap at all there are not like a water meter that ticks over, but are constantly taking heat readings to work out the joules used. The balancing of the systems can easily be put out by the smallest amount of scale in the system so in needs constantly cleaning and dosing, a decent size dosing unit is unit is a must. But you still get problems balancing each unit. Either with hot water or the under floor heating. Most residents don't use the under floor heating anymore due to the massive amount of free heat coming off the hot water rail. So you have paid for a massively powerful system where the customer only pays for what they use. Parts are not cheap, a couple of years in, and differential valves, TMVs and meters have been changed at a thousand of pounds cost across the 12 units. along with loads of hours work sorting the systems to be stable. The reading and billing admin and silly extra heat in the summer months the system turns out to be a mechanical engineers love child constantly burning the owners energy mix. If you have the money to install these system....pick something else. They are work
I have seen centralised boilers with Heat Interface Units in apartments becoming more common. It makes matters far easier for architects. No massive cylinder to take up space. No combi which is limited in its location. No awful looking flues and pressure discharge pipes on the outsides of buildings making them look ugly - one of my pet hates regarding pipes, flues and cables on the outsides of buildings. No gas meters and gas distribution pipes into flats. Many, many advantages. HMG is talking of phasing out gas for many reasons, mainly because of gas supply, as most is imported from Norway these days, with some even from Russia. They also pull the pollution card. When we had the North Sea full of gas, it was _High Speed Gas._ Wind and tide can make the power we need, so it looks like all electric - the way it was to be post war with nuclear - they said electricity would _"be too cheap to meter",_ as we have with water right now (most water is unmetered). Though I doubt HMG cares a hoot about buildings looking ugly. HMG is encouraging centralised boilers and district heating schemes. This reduces urban pollution as larger boiler can be monitored better, than hundreds of small boilers. It also makes matters safer as gas is out of flats. Saying all this, modern superinsulated flats, and houses, need little heat input for space heating. This also keeps out heat as well. Heat recovery ventilation can cool the home. Just a small simple, cheap, electric heating system - maybe just individual electric heaters in each room and may a small square (taking up far less space) water storage, or 11.5kW instant shower heaters. So, electric supplies to homes can be say, 140 Amps, not 100, to cope with instant hot water needs. Heat Interface Units look good for retro fits.
🤔 "this are hot at all Times" mine defo aren't. Takes a good 5 minutes to get hot water sometimes.. Need to convince my landlord to have a look.. Its also luke warm in the taps Half the time. Eg if I use radiators... I can't get hot water out the taps.. What could cause it as landlord doesn't believe anything is wrong
Worked on these in a retirement complex and found the biggest issue to be balancing over such a large system with many apartments. With ever changing heat demand balancing the whole lot is pretty much impossible. And with the legionella compliance and many TMV'S it was just a total nightmare it was the job that would never be finished unless you implemented common sense which is that legionella is not going to happen with instantaneous HW but the stupid paperwork 🤬
That sounds like a problem at the central boiler. Did it have low loss headers? It should have had. The system shown should be easier to balance as primary water from the main boiler only runs through the plates, not around the rads in each flat. The shown Heat Interface Unit has water from from the main boiler running through the CH plate at all times - it looks like 100% flow can be through the CH plate, or 100% through the DHW plate or ant proportion between. The flow into the unit is the _same at all times,_ no matter what the heat load is in the flat. The flow is *constant,* with a constant temperature. It never runs up or down, this is far easier to balance.
I believe it's designed so that as hot water demand increases, the primary (plant room) flow allowed through the central heating exchanger decreases proportionally.
@@puingu2806 Yes. *Three-way DHW priority diverting valve.* It looks like if there is no heat demand to a flat, full flow and temperature runs through the CH plate at all times. The thee way diverting valve looks like a DHW priority valve - a _modulating_ diverter valve, modulating to a temperature setpoint. Not like the 3-way valves in combi's, which are either on or off. But the valve is not one in with two outlet ports, having _two_ in, with _one_ outlet port. The reverse to most. CH into one inlet port, DHW into the other port, the outlet is back to the main boiler. If no DHW draw-off then the 3-way diverting valve moves over allowing water from the main boiler to run through the CH plate then return back to the main boiler. No mixing of hot and cold, as the valve just restricts the flow, or stops the flow, from the main boiler through the DHW plate. While restricting the flow through the DHW plate it opens up the other CH inlet port. lt allows water to increase flow through the CH port. Gledhill did this with a modulating pump in their thermal stores - just restricts flow through the plate to achieve the DHW setpoint. *Two-port CH valve.* The two-port CH valve just modulates up and down on then return from the CH plate, to maintain a setpoint temperature by merely restricting the flow through the CH plate. It will modulate or be even 100% full flow or off. If the 3-way diverter valve is blocking the route back, DHW has priority. I think I got that about right.
![Gucci Mane & Sexyy Red - You Don't Love Me [Official Music Video]](http://i.ytimg.com/vi/j7IBqyFKT4c/mqdefault.jpg)
www.mepstock.co.uk/admin/images/1548938236Commercial%20Catalogue%20WHOLE%20DOC%20Ed1.pdf
Who needs HIU courses when you have Dave on RUclips. Legend
Recall Dave teaching courses at Vokera. Top man top teacher.
Pictures are worth a thousand words, most heating systems make more sense when you see them drawn out, and a written sequence of operation helps.
Thank You
Great bit of kit in the right situation, we fit lots of these in assisted living flats. Work fantastically when set up correctly. Only down side is when the plant room boiler fails nobody has any heat or hot water.
Good video Allen. Very knowledgable gentleman, say hi to David for us!
Thank you honey.
That was a fantastic breakdown of the HIU.! It's all new to me but I've been enlightened.
Thank you sir🤝🏽
Excellent informative video welldone Alan pleasure meeting you at phex Chelsea. Great man
Great stuff. Explanations are perfect. Drawings better than mine 👏🏾👏🏾👏🏾
I’m so grateful for this video.
Thank you so much Alan and David.
I’ve just started a new job and there’s around 60 hiu’s
Incredibly informative and so helpful.
👍👍👍
Very helpful, easy when explained so well
Thanks very much for your comment, please consider subscribing to support the channel 🙂
Perfect explanation by both of you... i found this extremely helpful as a council leaseholder to understand the new unit I have been offered. Thanks so much!
Glad it was helpful!
Thanks very much for your comment, please consider subscribing to support the channel 🙂
Worked on district heating scheme for a number of years, these unit seem a great set up.
Did we explain them correctly? Thanks.
Brilliant as always Allen.
Thanks.
Great Allen work , this message is very helpful thanks
Loved the explanation! Thanks both
Good one Alan you really explain that perfectly.
Thank you kindly
Interesting that Allen, its not something i just didn't understand, I didn't even know they existed, but but pretty cler when explained by you, cheers :)
Thanks.
Great video. Really interesting. Cheers
Nice unit, He missed Chp as a heat and power source,which combined with a heat store is a great option, perhaps Vokera don't install them. Have worked on similar systems at hotels in Southampton using the City Geothermal system. 10 inch supply and return on those!
Brilliant Allen thank you for this! Happy Easter brother 🙏
My daughter bought a flat in London with this type of heating four years ago,nightmare constantly having no heating or hot water ,plant room failures engineers not able to balance flow and returns over the different floors, if you had heat somebody else didn’t.she lost so much time from work over giving access to engineers she sold the flat. Plus b g had the contract for energy and the tariffs were expensive.
Thanks for the feedback.
Although the video is only about the technical aspects of how HIUs work, I fully sympathise with your comment. District and Communal Heating schemes (You will be using one of these schemes if you have a HIU) are legally unregulated and residents are obliged to accept the monopoly that the heat provider is. So not only do end users have to accept the heat provider and are prohibited from exercising the freedom to switch suppliers, like a customer who has a system that heats their home's water (majority of UK), but if the heat provider charges an excessive amount or provides a bad service, the resident has no recourse as the industry is unregulated. The regulator, Ofgem, has no authority to get involved. This is a very important consideration when one is considering moving to somewhere that has a heat network. The heat provider can provide terrible service, charge you double what you would pay per kWh if you could choose your own supplier, and there is absolutely nothing you can do about it, other than quit the home, which is what your daughter sadly concluded. It is shocking that the industry is unregulated.
@@rossstevenson2532 Thank you for taking your time in adding your valuable insight.
Very good video
Thanks very much for your comment, please consider subscribing to support the channel 🙂
Brilliant video
Thank You
Congratulation Allen exellent video. exellent unit Macuk by Lovato.
Thanks.
Top bloke as usual
Thanks.
CHP is a option. You usually find them on really big buildings like , gym's Windsor Castle and Buck Palace . I prefer the cascade multiple boilers just in case one goes down. If the CHP goes down ya buggered UNLESS you have a cascade with CHP as backup. I kind of like this idea but if you are running a plantroom with multiple rooms then all you need is a local stat and the DHW on a return system. I think it might be a expense you don't really need.for example I do some work on uni students accommodation. All run off the plantrooms and each apartment has its own stat.
What's your thoughts?
👍👍👍👍👍
Hey Allen, great video mate. One question: If the last two radiators in this system are cold, but the second to last rad is hot at the TRV but a lot colder at the Lock shield valve - What would you suggest to do with the balancing? And second question if you don't mind, can I confirm that the Lock shield of the last rad in the line would be the 'most open valve'? I appreciate any advice you can give me. J
Interesting. As long as the overall execution does not cheap out, by specifying inappropriate valves which would make balancing between ‘apartments’ impossible and not providing redundancy (and automatic changeover) both in primary heat sources and circulating pumps
Thanks.
Greta vid. But my apartment has a HIU and an unvented cylinder. What’s that about? Is this correct?
Could I ask a question about Allen’s video,he mentioned the plate exchangers are always hot and ready, how is this achieved without being charged/metered for it ?
At the beginning of the video you stated there is no plate heat exchanger inside the unit. After taking the cover off there was a primary and secondary plate o.O
Always give Allan a 👍
Hi, hoping you could guide me in the right direction. I have the exact same unit in my flat. I can feel the hot water coming into the unit but when I turn the taps on the water is hot for 5 seconds and then freezing cold. What could I do to have this resolved ? Flat is only 2 years old
I have a question, where I work, the apartments residents mostly complain about their DHW, as in no hot water on most occasions, we have HIUs, is this a plantroom related problem?
I have an Evinox MTP50-10 which is opening and closing the HE control valve soon after the circulation pump kicks in and the pump keeps functioning. I'm reckoning it's an issue with the temperature sensors but I can't find the specs on them (S3, S4 and S5). Do you know if they're type K thermocouples or thermistors and what type? (2 of them look like thermistors and one looks like a thermocouple. I don't think they're original parts)
Allen, great tutorial, I have just started to learn HIU’s your explanation made a lot of sense , thank you so much! ;)
Hi I have one of those in my flat and want to move a radiator from its current place to somewhere along the wall. The question i have is does the person coming in have to bleed the whole system and fill it back up ? I have a feeling bleeding the system does not have to be done with a normal boiler but don't know if this is different or he is just saying this to hike up price?
Thank You
I would like an answer to this question, too.
thank you
You're welcome
got a problem with mine, the down stairs sink hot tap is working fine and getting really hot water but the up stairs sink hot water has been fluctuating and now hardly getting any hot water. what could it be .
hi, ever come across the situation where occassionally need to turn the heating out for hot water to come out of the taps? i.e. tap is turned to out but only cold water coming out of the tap until the heating is switched out which in turns heats up the water for it to come out of the tap hot?
As there is no gas supply, I assume any competent person can take off the cover and work on these? (and not be Gas safe reged).
Any idea why the DHW (Domestic Hot Water?) only activates when the heating room thermostat is either furred down past current room temperature or set to OFF?
There should be a delay if you have an actuator that opens and shut the primaries dependent on programmable stat calling on or off for heat
Thank You
Fitted loads of these
Good video, tbh allen district heat networks are becoming more popular. Starting watching it thinking where have I seen him before 😆🤦♂️
Thanks.
Its David.
Did I get this right? The two plates are fully hot at all times, with heat from the main boiler being constantly being pumped through them?
The domestic hot water plate will have a bypass before it, controlled by the mechanical blending valve.
@@Brijoolz
I thought that might be the case, as both valves could totally block circulation from the main boiler.
@@johnburns4017 yes. It might be an electrical actuator with controls. But yes, it will bypass when the dhw is up to temperature.
It can be any heat source.
In Aberdeen, lots of the council buildings, blocks of flats, all get heat via plate heat exchangers. There is a loop around the city that has various boiler plants that feed into the loop, then these feed into plates, instead of boilers. District heating.
@@Brijoolz
I doubt electrical as these units tend to have as little elecrical as possible in them. Quality mechanical controls last and last - but cost. Look at the quality of the electrical controls on low to mid priced combis. Even on cars, most of the breakdowns are due to electrical failures - ask the AA.
If an apartment has hot water in kitchen, second bathroom, but in end main bathroom that shower starts warm then loses heat. Is that likely a HIU issue or thermostatic valve issue? (Sink in that shower works well)
Thermostatic valve
Where I can find it? I am looking for its supplier
Can they work with water heated by ASHP?
District heating is becoming very big in the UK. I maintain over 2k properties in the Glasgow area. A lot of folk are still getting used to them but I think they are a good efficient set up. The company I work for specialises in biomass so the schemes primary heat source is biomass. A gas/oil back up is essential in case of primary boiler failure. Of course some units are better than others, as with gas boilers. Do you have fault finding videos that I could let our apprentices watch. A really informative video, thank you 👍🏻
I bet it’s nice for you when you just get money and never have to suffer the issues. Jesus Christ the detachment from reality.
@@Liusila Gosh I thought I was the only one in here think this. It's absolutely diabolical to live with. Never get enough pressure in the Water Heating System. Unvented cylinder much more effective with the premise of having a backup of a heating element just in case.
Subscribed 🎉
On the Callefi SATKF2000 there is a setting for "Return Temperature Limits", can anyone explain that for me please?
Hi I've got heating or hot water unit is saying fault 4
We have 12 of these installed in a new build block of flats for the last four years, as a facilities manager the system has been a nightmare.
The two cascading 100kw boilers on the low lost head system constantly heat the hot water rail from the plant room to 80 degrees.
The hot water rail is very well insulated but still cause massive secondary heating of the flats in summer and the whole building. It is also not helped as the flats are modern, well insulation and pressure tested to pass the energy performance certificate, there's no were for the heat to go. This has resulted in flats being above 30 degrees, and elderly clients passing out as result of the flats not being able to lose heat.
The whole complex is constantly warm posing a problem to delivering cold water that is below 21 degrees as by the nature of the system the cold water is bought so close to the interchanged units and uses cavities next to the mega hot water rail pipes.
And then who pays for the hot water rail? Its the landlord 24hrs a day 365 days a year, just so a tap can delver hot water 20 seconds faster than a combi.
The taking of kilojoules readings and billing is admin heavy and takes up a stupid amount of time. So do buy the £10k software to try and save some time but it also important as the kilojoules meters batteries go flat and are not cheap at all there are not like a water meter that ticks over, but are constantly taking heat readings to work out the joules used.
The balancing of the systems can easily be put out by the smallest amount of scale in the system so in needs constantly cleaning and dosing, a decent size dosing unit is unit is a must. But you still get problems balancing each unit. Either with hot water or the under floor heating. Most residents don't use the under floor heating anymore due to the massive amount of free heat coming off the hot water rail. So you have paid for a massively powerful system where the customer only pays for what they use.
Parts are not cheap, a couple of years in, and differential valves, TMVs and meters have been changed at a thousand of pounds cost across the 12 units. along with loads of hours work sorting the systems to be stable. The reading and billing admin and silly extra heat in the summer months the system turns out to be a mechanical engineers love child constantly burning the owners energy mix.
If you have the money to install these system....pick something else. They are work
I have seen centralised boilers with Heat Interface Units in apartments becoming more common. It makes matters far easier for architects. No massive cylinder to take up space. No combi which is limited in its location. No awful looking flues and pressure discharge pipes on the outsides of buildings making them look ugly - one of my pet hates regarding pipes, flues and cables on the outsides of buildings. No gas meters and gas distribution pipes into flats. Many, many advantages.
HMG is talking of phasing out gas for many reasons, mainly because of gas supply, as most is imported from Norway these days, with some even from Russia. They also pull the pollution card. When we had the North Sea full of gas, it was _High Speed Gas._ Wind and tide can make the power we need, so it looks like all electric - the way it was to be post war with nuclear - they said electricity would _"be too cheap to meter",_ as we have with water right now (most water is unmetered). Though I doubt HMG cares a hoot about buildings looking ugly.
HMG is encouraging centralised boilers and district heating schemes. This reduces urban pollution as larger boiler can be monitored better, than hundreds of small boilers. It also makes matters safer as gas is out of flats.
Saying all this, modern superinsulated flats, and houses, need little heat input for space heating. This also keeps out heat as well. Heat recovery ventilation can cool the home. Just a small simple, cheap, electric heating system - maybe just individual electric heaters in each room and may a small square (taking up far less space) water storage, or 11.5kW instant shower heaters. So, electric supplies to homes can be say, 140 Amps, not 100, to cope with instant hot water needs.
Heat Interface Units look good for retro fits.
🤔 "this are hot at all Times" mine defo aren't. Takes a good 5 minutes to get hot water sometimes.. Need to convince my landlord to have a look.. Its also luke warm in the taps Half the time. Eg if I use radiators... I can't get hot water out the taps.. What could cause it as landlord doesn't believe anything is wrong
No heat exchanger he says takes the cover off and there’s two 😂
Worked on these in a retirement complex and found the biggest issue to be balancing over such a large system with many apartments. With ever changing heat demand balancing the whole lot is pretty much impossible. And with the legionella compliance and many TMV'S it was just a total nightmare it was the job that would never be finished unless you implemented common sense which is that legionella is not going to happen with instantaneous HW but the stupid paperwork 🤬
That sounds like a problem at the central boiler. Did it have low loss headers? It should have had. The system shown should be easier to balance as primary water from the main boiler only runs through the plates, not around the rads in each flat. The shown Heat Interface Unit has water from from the main boiler running through the CH plate at all times - it looks like 100% flow can be through the CH plate, or 100% through the DHW plate or ant proportion between.
The flow into the unit is the _same at all times,_ no matter what the heat load is in the flat. The flow is *constant,* with a constant temperature. It never runs up or down, this is far easier to balance.
How the two thermostatic valves interplay needs a little more explanation.
I believe it's designed so that as hot water demand increases, the primary (plant room) flow allowed through the central heating exchanger decreases proportionally.
@@puingu2806
Yes.
*Three-way DHW priority diverting valve.*
It looks like if there is no heat demand to a flat, full flow and temperature runs through the CH plate at all times.
The thee way diverting valve looks like a DHW priority valve - a _modulating_ diverter valve, modulating to a temperature setpoint. Not like the 3-way valves in combi's, which are either on or off. But the valve is not one in with two outlet ports, having _two_ in, with _one_ outlet port. The reverse to most.
CH into one inlet port, DHW into the other port, the outlet is back to the main boiler.
If no DHW draw-off then the 3-way diverting valve moves over allowing water from the main boiler to run through the CH plate then return back to the main boiler.
No mixing of hot and cold, as the valve just restricts the flow, or stops the flow, from the main boiler through the DHW plate. While restricting the flow through the DHW plate it opens up the other CH inlet port. lt allows water to increase flow through the CH port. Gledhill did this with a modulating pump in their thermal stores - just restricts flow through the plate to achieve the DHW setpoint.
*Two-port CH valve.*
The two-port CH valve just modulates up and down on then return from the CH plate, to maintain a setpoint temperature by merely restricting the flow through the CH plate. It will modulate or be even 100% full flow or off. If the 3-way diverter valve is blocking the route back, DHW has priority.
I think I got that about right.
Just a combination boiler with no flame.
Thanks.
You wouldn’t have a plate on the heating on a combi though. Thanks.
👍🤓👍
Thanks.
Much prefer my Evinox unit 🙂
Hello Alan do you have a Instagram account? Thank you
No, sorry
But why does the heating not work lol
Brilliant video
Very good video
Thanks.