Large boiler, small .......

[John D v2.0]

In my experience it's not possible for everyone who develops a system to know about all the emergent behaviour that results from the system.
That's what quality assurance and user feedback and research is designed to do.
A system designer who thought they had nothing to learn from people who use their system would lose customers quickly due to poor attitude.

 

[hard-work]

A boiler is only a part of a system.

 

[bernardgreen]

A system designer who thought they had nothing to learn from people who use their system would lose customers quickly due to poor attitude.

Feed back is good but it is after the item has been put to market and thus too late to affect the basic design. A new version has to be designed.

The design team tasked with designing a new telephone switchboard were required to spend several hours manning the company's switch board to be able to fully appreciate tasks that a switchboard operator performed.

 

[ericmark]

I understand why a boiler size is important, and the losses every time a boiler switches off, however although I know we don't want a boiler to cycle, I look at these pages, and what is for sale in Screwfix and other outlets and we have 1000's of thermostats sold which simply switch the boiler on and off.

There is a huge advertising campaign to sell Hive. This simply switches on/off, now Nest or EvoHome I could understand, but how can the industry try selling Hive on one hand, and then say we should modulate the boiler not simply switch it on/off.

I will hold up my hands, I made a mistake, OK I am an electrician not a heating guy, but I bought eTRV heads which although wifi don't actually tell the boiler what output is required. In fact don't to this day know how it should be done. Theory is great, eTRV head tells a hub (Thermostat) temperature of each room, and then the hub tells boiler how high flame should be.

But my boiler is not OpenTherm, so if I use EvoHome all it can do is turn boiler on/off, rather defeats the whole idea, and if I use the Bosch modulating thermostat it only detects the temperature of one room.

So I use the TRV to control boiler by return water temperature, so I still want a thermostat to turn off the boiler once it has reached the point where it can't turn down any further and is cycling, the installers ripped out the hard wired thermostat, so has to be wireless, cheap wireless thermostats don't fail safe, as I found out, but expensive types have anti hysteresis software built in so before the area monitored hits the set temperature it starts to cycle the boiler, but hang on whole idea is to reduce cycling not increase it.

So with whole industry in turmoil, where the major manufacturers can't get their act together to produce an integrated product, how do you expect to explain it to Joe Public?

And as to altering room temperatures through the day, again anti hysteresis software seems to make that rather hard, forget geofencing, OK I know what is wanted is for the radiator to store as little heat as possible, and to circulate the air, altering the rate of circulation to match room requirements, the radiators are made with multi speed fans which change speed to match room requirements, able to heat (and if a air con is installed also cool) the room very quickly, however these don't have TRV's so really do need a connection to the eBUS of the boiler, but I am already 67 and so likely will only need the system for 25 years, and it will take well over that time to pay back the money saved with fan assisted radiators once you look at price of building management system.

Then of course we add storage, I have seen a house with two massive well insulated tanks which takes the energy from solar panels, wood burners, and a LPG boiler and as an when required pumps it around the house, also looked at the Willis system to heat the tanks from top down, all very cleaver, but would any one live long enough to get pay back?

I went to sons first house, he left the heating on 24/7 because he said it took ages to reheat house, but could maintain the heat without a problem. It was all due to lock shield valves being wide open, once warm the TRV's reduced the flow in each radiator, but until warm the hot return water modulated the boiler so it had very low output and heated one room at a time. That is not the only house where the installers have left the property with the lock shield valves wide open, it took a lot to convince my son to turn down the radiators to get house to warm up quicker.

The installers are their own worst enemy, simple logic, last house took 4 hours to heat up with a 25 kW boiler, this is a bigger house, so it needs a bigger boiler. Fact it was all down to last house had lock shield valves wide open does not come into the equation. There are some really good installers, but also there are even more cow boys. The ones who did this house even broke the law with a power shower on a combi boiler, don't blame Joe Public, it is the industry that is to blame.

 

[bernardgreen]

So with whole industry in turmoil, where the major manufacturers can't get their act together to produce an integrated product, how do you expect to explain it to Joe Public?

It suits the industry for Joe Public to remain ignorant of the realities of heating and hot water systems. That ignorance makes Joe Public unable to see the reality behind the items / system being sold to him and thus question the validity of the information given to him by the installer.

EDIT It doesn't help Joe Public when the installer is also unable to see the reality of the claims made by various manufacturers

 

[Dan Robinson]

It suits the industry for Joe Public to remain ignorant of the realities of heating and hot water systems. That ignorance makes Joe Public unable to see the reality behind the items / system being sold to him and thus question the validity of the information given to him by the installer.

EDIT It doesn't help Joe Public when the installer is also unable to see the reality of the claims made by various manufacturers

It doesn't help Joe public to have old farts like you sticking their oar in in the misguided belief that they know more than they do. The industry is not in turmoil. ItIjust had too many people like you pretending to know what they're about affecting clueless muppets like Eric.

Worcester, Viessman and Vaillant all have fully integrated control systems. But at the same time, what is"fully integrated"? Those of us that know what we're about can put together our own systems that can behave the same if not better. With the benefit of simple off the shelf repair strategies.

It's funny how many people moan about the lack of decent controls when it actually boils down to the fact that they're not willing to spend the money.

As demonstrated with Eric and the half arsed system he's installed for "mother". He's convinced himself it's what he wants despite knowing and admitting that it is not really.

 

[hard-work]

I am in France, the standard of plumbing is superior all around. Hot & cold manifolds with plastic pipe to each outlet is common. Similar to UFH manifolds. Many of the pipes from the manifold to outlets are 10mm or less, as that is all they need to be. One jointless pipe to each outlet, like running cable. All off the shelf stuff. Easy to do.

I recall maybe Gledhill tried to sell a manifold H&C system, presumably for the new build market, but few bought it.

See how many Wondervalves are fitted with flow regulaltor cartridges, to balance mains pressure H&C systems. Few know what they are, so showers are greatly effected by other outlets when drawing water.

Look at the cheap and nasty flimsy looking copper cylinders we fit. Few stainless are fitted.

In general British plumbing is an international joke. I am very serious when I write that.

 

[hard-work]

Integrated controls are easy these days. Many boilers, Intergas for one, come with Opentherm as standard, interated weather vompensation. Just use the Opentherm stats.

Few 'plumbers' know what Opentherm is. Try getting them set up the system? That means they have to know how the control system works first which for most is beyond them. I have seen 2 and 3-way valves connected externally on Intergas boilers, because they never knew they could be connected directly to the boiler with the boiler's control system doing the work. They can't figure out the diagrams in the manual.

 

[hard-work]

It's funny how many people moan about the lack of decent controls when it actually boils down to the fact that they're not willing to spend the money.

More not willing, or incapable, to learn domestic CH control.

I have seen CH systems laid out and wired (two 2-port valves) with gravity fed cheap copper cylinders, exactly as they were done in 1969. But they fit a boiler with sophisicated 'integrated' controls, with the boiler just switched in and out, as in 1969, with its energy saving and comfort enhancing controls totally ignored.

 

[bernardgreen]

Few 'plumbers' know what Opentherm is.

They don't need to know how it works. Plug and play and it will work. It was after all based on a well proven industrial data communication system called FieldBus developed some time in the 1970's

It was "improved" by removing the need to observe polarity when wiring the system. This required bridge rectifiers in slave nodes to cater for reversals of the pair and reduce immunity to induced noise on the pair.

Given that domestic installs are very short cables the reduced immunity was not seen as problem. ( Maximum cable length for FieldBus is 1800 metres )

 

[ericmark]

This clueless muppit tried to follow advice given and accept other than breaking the law the installers know what they are doing.

I was told again and again you don't fit wall thermostats in the same room as TRV, but it was only after I fitted a TRV to same room as wall thermostat that the system started to work.

It was only after I moved back into my dad's house that I realised how many things the installers got wrong, and cost cutting was not the reason, a rather expensive thermostat was fitted, but it was a simple on/off type, but boiler is a modulating type.

Being fair not only the heating guys, I have seen poor workmanship from near every trade, as one time to join a union you had to be indentured so if you only used trade union members you got a reasonable job.

Then government killed union power and it has been replaced with organisations only interested in making money, if a tradesman is a member of trusted whatever that means their useless.

 

[bernardgreen]

It doesn't help Joe public to have old farts like you sticking their oar in in the misguided belief that they know more than they do.

It doesn't help Joe Public to have installers sticking their pipe work and wiring in in the mis-trained belief that they are competent. Not only does it not help Joe Public it can and too frequently does leave Joe Public with a poor system and un-expectedly high running costs.

 

[ericmark]

So maybe we need to return to basics? Central heating has a central heater and the heat is distributed around the home using air, water, or steam, I have never classed storage heaters as central heating where they are individual units, only where there is a central heat store and the energy is distributed and controlled with either air or water is it central heating.

A boiler produces steam which was piped around the premises, however I have not seen steam used in domestic, but the old Lancaster boiler was a common sight. Today we don't boil the water, but the name has stuck.

My first house used hot air not water, and because the air was circulated around the house a single thermostat was able to control the temperature in all rooms, circulating air past single glazed windows however resulted in heavy losses, so expensive to run, second house was open plan, designed to have one central gas fire, and the heat would go up open plan stairs to all bedrooms too. However there was no thermostat on the gas fire, so it was supplemented very quickly with central heating using micro bore.

It had problems in that the bedrooms got too hot, but TRV on bedroom radiators cured that, and again since open plan one thermostat controlled whole house, the fan assisted radiator was moved, it was under the stairs, but it sent too much heat up the stairs, so moved to the front door, that was the only downstairs radiator with a thermostat.

Both houses the central heating worked well, even if first house was expensive to run.

Dads house was very different, there were doors on the down stairs rooms, each room originally had coal fires, these were changed to coke fires, but there was a major design fault, there were no vents to allow combustion air into the rooms by the fires, so they caused huge drafts, and the steel works closed, so also the supply of cheap coke, so central heating was fitted, because the flue was balanced it removed the problem with drafts, however it was really manual control, my parents would hourly alter the thermostat, where in my house the programmable thermostat was never touched.

When my dad died and I was left looking after my mother I realised she was constantly altering the thermostat, and she complained her down stairs bedroom was cold, found near every lock shield valve wide open, up stairs was unused so closed all TRV to frost protection and fitted a heavy curtain in front of the stairs.

However although I get the bedroom warmer having a thermostat in the hall I found the living room varied hugely, I realised it was mainly due to bay windows and the TRV was too slow acting, when the sun came out within an hour the room would shoot from 21°C which I have set TRV to, and reach 25°C some times even higher, first idea was move thermostat into living room, improved, but not really a success. Once I moved to electronic TRV heads then stopped the room over heating.

However since the eTRV head could be programmed, I tried setting the temperature to vary letting the living room cool at night, and bedroom cool during the day, found fabric of house stored too much heat, on a very cold night the room may cool to 17°C but eTRV head set to 16°C, and then in the morning the hall thermostat would turn off boiler before rooms had heated up. So second programmable thermostat fitted in kitchen, this was to keep boiler running for longer in the morning.

However the hall temperature and so also the wet room would plummet when front door opened, and then take an age to recover, open the lock shield valve and hall would get warm and rest of house cold, close the valve and hall cold, there was no TRV in hall, kitchen, or wet room.

So against all the advice given here I fitted a TRV to hall radiator, it was like magic, after years trying to balance the temperatures and get the house to automatic adjust temperatures without continually altering the thermostat I had finally got it to work, front door opened and the TRV would also open and reheat hall, but before the wall thermostat switched off the whole of the central heating the TRV would close again so only on the warmest day would the wall thermostat turn off the boiler. At last it worked.

However my point is my father paid for central heating to be fitted twice, second time the cold water tank was leaking so he moved to a combi boiler and did away with the water tanks. Both times the control was rotten, two different firms, both large, not sole traders, and neither time did it work properly. The plumbing was fine, except for power shower on mains water supply, but that was fixed FOC, well I had to buy a new regulator for shower but they fitted it.

But they seemed to have no idea how to control the heating, second time fitted the boiler was a modulating type, it would work with a modulating thermostat but the hard wiring for thermostat was ripped out and a wireless one fitted, good quality yes, but it would never have controlled the two main rooms as fitted.

They advertised as heating engineers, they were simply pipe fitters, even the solder was lead free so could not call them plumbers. Fitting 36" steel pipes a pipe fitter is a highly skilled guy, I have worked with them pre-heating and stress reliving the pipes, but 15 mm you could kick into place. Not that it needed 15 mm. The pipes are exposed with little or no attempt to hide them. I just hope my dad got two cowboy firms.

My brother-in-law had a system fitted and that clearly showed some people do have the skill, twin water tanks with solid fuel, solar and LPG all used to heat the house, I never questioned how it all worked, as it did, you only question it when it don't work. How my dad let them get away with if I don't know, he spent his whole life working with steam and heating systems, he ran the power station in a steel works, that's a real power station controlling steam, water, gas and electric around the steel works, not just electric. He knew all about boilers, and he told me no such thing as a condensate boiler, you can't extract the latent heat of evaporation in a boiler producing steam, and if it does not produce steam its not a boiler, it is just a water heater.

 

[hard-work]

They don't need to know how it works.

They need to know what Opentherm does and its advantages. They do not need to know the electronics behind it.

 

[John D v2.0]

He knew all about boilers, and he told me no such thing as a condensate boiler, you can't extract the latent heat of evaporation in a boiler producing steam, and if it does not produce steam its not a boiler, it is just a water heater.

That's a long post but i read it all and disagree with the final point. The ability to condense depends on the return temperature not the flow temperature, and even that assumes there's no heat pump or similar. Do you mean a steam boiler has a steam return rather than just a steam flow? You could alternatively preheat the incoming air and condense at that point.