boiler stat temperature

alfa beta

thanks for all the replies - had no idea such a debate would ensue!!

anyway, bearing in mind what Heinblood said I turned the stat down to a level where I thought the return temp might be around about the 47 mark and the result was (obviously) a freezing cold house!!

so it's back up around the mid/late sixties mark where the installer originally set it and i guess that's where it's staying - presumably this means the burner is not working to its greatest efficiency now but at least the house warms up (which is sort of the idea of a heating system!)

Pity I didn't know about the whole return temp/condensate thing before deciding which heating method to go with - would have looked more closely into UFH if I had.

Live and learn I guess!

Thanks again all.

heinbloed

@ alfa beta:

Using a condensing boiler in a non-condensing modus is against the manufacturer's instructions.
Condensing boilers MUST condense because they're sealed systems. If no condensate is created (the artificial water in the condensate trap) then the system isn't sealed anymore.
Better get a heating engineer in, someone who cares about health and safety.

You're risking the destruction of the boiler by overheating it, of the house via the fire risk and gas poisoning because of emissions escaping from the condensate or from the flue pipe.

We have read here in the forum (first page of this thread and further) that people who claim to be plumbers/installers of condensing boilers aren't capeable to understand the manual coming with the condensing boiler. So better get an expert controlling the job after trusting those. Before starting the boiler!

The risk of gas poisening can be minimalised if the c.-boiler is installed outside in the fresh air. But the other risks remain.
Note that your fire/home/accidental insurance propably doesn't cover for accidents caused by installations installed and operated against the manufacturer's recommendations.

Good luck!

MicktheMan

alfa beta wrote: »

at least the house warms up (which is sort of the idea of a heating system!)

Not correct and is a common misunderstanding!
A heating system's primary role is to replace the heat lost from a house through air infiltration and insulation weaknesses! If there were no nett heat losses then there would be no need for a conventional heating system - this is the principle of passive houses.

heinbloed

heinbloed wrote: »

Using a condensing boiler in a non-condensing modus is against the manufacturer's instructions. !

All condensing boilers condense from cold, just because it's not condensing all the time doesn't make it unsafe, so what you have posted is nonsense.

heinbloed wrote: »

Condensing boilers MUST condense because they're sealed systems. If no condensate is created (the artificial water in the condensate trap) then the system isn't sealed anymore.!

Again what you have posted is nonsense.

heinbloed wrote: »

You're risking the destruction of the boiler by overheating it, of the house via the fire risk and gas poisoning because of emissions escaping from the condensate or from the flue pipe. !

More nonsense:pac:

heinbloed wrote: »

The risk of gas poisening can be minimalised if the c.-boiler is installed outside in the fresh air. But the other risks remain.
Note that your fire/home/accidental insurance propably doesn't cover for accidents caused by installations installed and operated against the manufacturer's recommendations. !

How many reports have you written on unsafe installations, what do you base your nonsense on?
Domestic boilers are tested by manufactures for all types of installation designs and must meet a given safety criteria, so you are wrong to assume they haven't been tested for safety connected to a common rad system where condense is minimal, it is not dangerous so stop talking out of your backside and confusing the issue.

alfa beta

alfa beta wrote: »

bearing in mind what Heinblood said I turned the stat down to a level where I thought the return temp might be around about the 47 mark and the result was (obviously) a freezing cold house!!
.

If you have stored hot water and reduce the boiler thermostat setting below 60c you risk legionnaires if left for a long time and have no secondary heat source for your hot water cylinder.

alfa beta wrote: »

so it's back up around the mid/late sixties mark where the installer originally set it and i guess that's where it's staying - presumably this means the burner is not working to its greatest efficiency

you are only losing about 3,4% on efficiency by the boiler not condensing all the time.

alfa beta wrote: »

Pity I didn't know about the whole return temp/condensate thing before deciding which heating method to go with - would have looked more closely into UFH if I had.
.

There is a lot to be said for keeping things simple, Gary:).

heinbloed

@ gary71:

Put facts on the table.

Any condensing boiler manual available which states that the operation of a condensing boiler is safe when not operating in a condensing modus?

Nothing? Not 1 link?
Why?

I can make for my own words,
so I pick up the non-sense you have adressed at alfa-beta:

Quote:
Originally Posted by alfa beta
bearing in mind what Heinblood said I turned the stat down to a level where I thought the return temp might be around about the 47 mark and the result was (obviously) a freezing cold house!!
.

If you have stored hot water and reduce the boiler thermostat setting below 60c you risk legionnaires if left for a long time and have no secondary heat source for your hot water cylinder.

We're talking about condensing boilers, gary71.

Their thermostats (plural,there are several with each c.-boiler) can be set individually, read the manual.
That a flow temperature of more than 60 degrees Celsius can be achieved AND a return temperature of less than 30 degrees Celsius is simple. Again: read the manual.


Further you wrote, adressed at alfa-beta:

Quote:
Originally Posted by alfa beta
so it's back up around the mid/late sixties mark where the installer originally set it and i guess that's where it's staying - presumably this means the burner is not working to its greatest efficiency

you are only losing about 3,4% on efficiency by the boiler not condensing all the time.

This is simply not true. Not the operational temperature (here the temperature at the flow/output) is decisive when it comes to energy efficienct usage.
Again: read the manual.
And try to understand the laws of physics.


So.

And now we wait for your facts. The manual please.

(Maybe someone could help out gary71?)

Billy Bunting

Didn't realise Condensing boilers were such a pain in the arse to commision, can't recall reading half this stuff in any manual. :rolleyes:

heinbloed

heinbloed wrote: »

Put facts on the table??)

. you need to work on a few boilers:pac::pac::pac:

heinbloed wrote: »

Any condensing boiler manual available which states that the operation of a condensing boiler is safe when not operating in a condensing modus???)

All domestic condensing boilers will produce sufficient condense to keep the trap full during the daily operation, modern domestic gas boilers have anti cycle and a logic that will try to achieve a delta T of 20 degrees during normal operation, due to this a boiler will produce sufficient condense to keep the trap full, a condensing boiler doesn't stop being a condensing boiler just because it achieves a higher temperature than you agree with, i have never found a dry trap.

heinbloed wrote: »

@ We're talking about condensing boilers, gary71.??)

thanks

heinbloed wrote: »

@ Their thermostats (plural,there are several with each c.-boiler) can be set individually, read the manual.
That a flow temperature of more than 60 degrees Celsius can be achieved AND a return temperature of less than 30 degrees Celsius is simple. Again: read the manual.?)

Thank you for that, in your experience how many installers want or care to know that information, they want to take it out of the box fit it and walk away, i find getting some installer to fit a filling loop and maybe wire a s-plan system is hard enough, if i start explaining the operation of a thermistor and how the boiler logic works then they tend to tell me to feck off, but you must have a gift.

heinbloed wrote: »

@ This is simply not true. Not the operational temperature (here the temperature at the flow/output) is decisive when it comes to energy efficient usage.
Again: read the manual.
And try to understand the laws of physics.?)

I am just a simple gas fitter:o who knows boilers, but I'll work on the physics;).

Micky Dolenz

Less of the "nonsense" talk please.

Refute the points with fact, not by sniping.

yoshytoshy

Can I make it perfectly clear to anyone who is bothering to continue reading this thread ,that there isn't half the information available for boilers on the internet.

I've got hundreds of engineers notes on different boilers ,that I got directly from them.
Myself and people like gary71 don't have links for a lot of the stuff we know ,it comes with the job.

heinbloed

Billy Bunting wrote:

Didn't realise Condensing boilers were such a pain in the arse to commision, can't recall reading half this stuff in any manual.

I'm afraid that's the situation we're in.

Usually it states in the manuals how to install and operate a condensing boiler. And not how NOT to install and operate them. It's a question of literacy to understand the manual of a car, for example, it won't state that the subject isn't fit for diving or baking...

In the USA the writers of manuals go great ways of describing what not do do with the product. Here in the EU we are expected to stick to the facts of life, i.e. 'creating' a reality is out of question.

slavetothegrind

ok i'll bite.

can you describe the last installation you did heinbloed.

in all fairnesss we stand to learn a considerable amount here if you could tell us how in one real world case you commissioned a boiler satisfying the critieria you have laid out here.

Even one case of a boiler failing in a dangerous manner because it was operated at too high a temperature by the customer.

heinbloed

Slavetothegrind wrote:

ok i'll bite.

can you describe the last installation you did heinbloed.

in all fairnesss we stand to learn a considerable amount here if you could tell us how in one real world case you commissioned a boiler satisfying the critieria you have laid out here.

Even one case of a boiler failing in a dangerous manner because it was operated at too high a temperature by the customer.

Answer:
I can indeed.

Advice:
If someone has to learn something concerning theoretical physics then school is the best place, I think, slavetothegrind. And for literacy it is propably the best place to go, reading AND understanding an installer's manual couldn't be done without.
The chatroom as a source of information isn't much worth without de-facto data, without references or links where to get them.
The internet chatroom or forum isn't worth anything to the student who shows a disregard to the written word.


Question:

Maybe you, slavetothegrind, can help gary71, others have failed so far:
Gary71 was asked to put some data on the table, some facts. But hasn't done so despite been asked twice, so my question again:

Which condensing boiler manufacturer states officially that his condensing boiler is safe to use when not using it in a condensing modus?

Any information available? Like for example a copy from an installer manual or from a user manual ? A homepage from the manufacturer? Safety advise from an official heating engineers association, plumbers organisation? Anything at all?

Show us your competence with publishing facts, slavetothegrind. And help gary71.....

Billy Bunting

slavetothegrind wrote: »

ok i'll bite.

can you describe the last installation you did heinbloed.

in all fairnesss we stand to learn a considerable amount here if you could tell us how in one real world case you commissioned a boiler satisfying the critieria you have laid out here.

Even one case of a boiler failing in a dangerous manner because it was operated at too high a temperature by the customer.

I think thats a no then :rolleyes:

heinbloed

heinbloed wrote: »

Maybe you, slavetothegrind, can help gary71, others have failed so far:
Gary71 was asked to put some data on the table, some facts. But hasn't done so despite been asked twice, so my question again:

Which condensing boiler manufacturer states officially that his condensing boiler is safe to use when not using it in a condensing modus?

Any information available? Like for example a copy from an installer manual or from a user manual ? A homepage from the manufacturer? Safety advise from an official heating engineers association, plumbers organisation? Anything at all?

Show us your competence with publishing facts, slavetothegrind. And help gary71.....

Combi boilers run at high temperatures when running for hot water, producing very little if any condense, so following your logic all combi boilers are dangerous as they are not condensing?

Heinbloed i do this for a living as do others posting here, i have made a lot of mistakes until i got to the point that i don't make so many anymore, i constantly have to re skill as new products come out, i am as good as you will get in my field of work and i am more than happy to share my practical experience, you have misunderstood the workings of a condensing boiler, you can except that or not, I'll leave it up to you;)

yoshytoshy

Some people taunt to extract information out of people ,deliberately playing the fool while displaying a "knowledge".

Experts like heinbloed get people killed.

jeepers101

Just curious heinbloed, if setting the boiler above 50 degrees is dangerous, why does the boiler let you do it? :rolleyes:

jeepers101

jeepers101 wrote: »

Just curious heinbloed, if setting the boiler above 50 degrees is dangerous, why does the boiler let you do it? :rolleyes:

If only i thought of that, i could of saved all that pontificating:D

Billy Bunting

jeepers101 wrote: »

Just curious heinbloed, if setting the boiler above 50 degrees is dangerous, why does the boiler let you do it? :rolleyes:

I think you'll find that Trolls don't have answers to questions, and by definition our heinbloed is a Troll.

Micky Dolenz

Billy Bunting wrote: »

I think you'll find that Trolls don't have answers to questions, and by definition our heinbloed is a Troll.

If you have a problem with a post or a poster, report it or PM a Mod.

We will not have members of this community accuse each other of being trolls.

DoneDL

I think this thread has gone on long enough, are condensing boilers a better option than a standard boiler, yes. Is it reasonable to replace an under performing gas boiler yes, Is it reasonable to replace a healthy oil boiler no. It is a legal obligation on any installer to replace old for new or fit from new with a condensing boiler. The system should be clean and balanced to guarantee that the boiler stays as long as possible in condensing mode. The system should be controlled to at least meet the minimum standard of controls required under the regulations. The system should be explained to the customer so that they get the best possible use out of it and achieve the best savings they can without any loss of comfort. There is no need for this ridiculous sniping and undermining of each other which helps no one at all.

heinbloed

Jeepers did ask:

Just curious heinbloed, if setting the boiler above 50 degrees is dangerous, why does the boiler let you do it?

Is it dangerous to set the flow above 50 degrees Celsius? Well, as far as I know it isn't, but who said so anyhow? A manual?

Different question: if it unsafe to drive the car against a tree why does the car let you do it?

You see the risk of evaporating the contents of condensate trap arises when two conditions are met:
1. the boiler runs, fires, produces heat and
2. no condensate is created.

So running the condensing boiler at 95 degrees Celsius is not unsafe (with the boilers I know) as long as a condensing is guaranteed. Meaning the water created by the combustion process is cooled down in the boiler to guarantee a permanent fill of the condensate trap.

Risky it becomes when the condensing temperature isn't reached anymore.
And this realy depends on the fuel type used and (with the standard household condensing boiler) on the return temperature.
Again: on the return temperature.
And not on the flow temperature.

What some installers don't know, or at least pretend not to know.

In a closed system/chamber (here the condensing boiler) a negative hydraulic pressure is created when this chamber is warmed up. Meaning that water puddles will evaporate. The warmer the air gets the more water will be taken up by it.
When a boiler fires, creates heat the air in it will dry any surface.
This is the case with any type of boiler.
The phenomena is called a negative hydraulic pressure (as far as I know, don't nail me down on this). In laymen's term: a drying process starts.
This drying process has an impact on ALL water present in the chamber/boiler.
With the consequence that water which might be present in the condensate trap will evaporate.
And in consequence of this evaporation process the water level will sink in the trap until a free passage of room air/sewer gases/combustion gases is possible.

And this should never happen. The condensing boiler MUST be run as a closed system, getting his air only from the designed air-inlet and losing the combustion gases only through the designed outlet.
And NOWHERE else.
So it says in every manual of every condensing boiler, basic logic that is.

Thanks for asking!

Micky Dolenz

Interesting heinbold.

It might be worth flinging a few emails at the makers to see if they respond.

jeepers101

Heinbloed, can I ask where you're getting all this information from? I read through a manual for a very popular Vokera boiler and it doesn't say (as far as I can see) anything you've been talking about. Any installer who has read this manual would presumably also be, at no fault of his own, none the wiser to the risks you're talking about.

The only correlation I can find is that they advocate a sealed system over a f&e one but give no reason as to why.

Micky Dolenz

Micky Dolenz wrote: »

Interesting heinbold.

It might be worth flinging a few emails at the makers to see if they respond.

I am responsible for all technical issues that arise for a boiler manufacture in Ireland and the North, I have never found a dry trap or a unsafe situation described by HB, there are no reports from recently or the past of a domestic condensing gas boiler not producing sufficient condense to keep a boiler safe in Ireland or the North, to be sure i have searched across Europe for the same, no reports found. I would be interested to know if anyone working on boilers has found this safety issue HB has experience of.

Micky Dolenz

gary71 wrote: »

I am responsible for all technical issues that arise for a boiler manufacture in Ireland and the North, I have never found a dry trap or a unsafe situation described by HB, there are no reports from recently or the past of a domestic condensing gas boiler not producing sufficient condense to keep a boiler safe in Ireland or the North, to be sure i have searched across Europe for the same, no reports found. I would be interested to know if anyone working on boilers has found this safety issue HB has experience of.

Ok, But lets look at this from another angle. Is it theoretically possible? I think it absolutely is possible but highly unlikely.

Give a situation the right conditions and anything is possible.

A boiler that hasn't be used for a few months over summer will have a dried out trap. Will there be an escape of POC if only for a few minutes?

Micky Dolenz

Micky Dolenz wrote: »

Ok, But lets look at this from another angle. Is it theoretically possible? I think it absolutely is possible but highly unlikely.

Give a situation the right conditions and anything is possible.

A boiler that hasn't be used for a few months over summer will have a dried out trap. Will there be an escape of POC if only for a few minutes?

I would agree that anything is possible, i have no problem with the theory, i just have never seen it.

sanbrafyffe

since its a condensing bolier make sure it was commisioned

alfa beta wrote: »

Hi - quick query

Got a firebird condensing oil burner and rad system (2.5k sq foot house with three zones - furthest rads would be abot 30 metres from the burner.)

Just wondering what temp people set the stat on the burner to. Mine is currently around the 65 degree mark (this is what the plumber originally set it to day one).

I feel the house would benefit from a nudge in the upward direction but I just want to make sure I don't do anything stupid by setting that temp too high.

ta.

heinbloed

Hi jeepers!

You wrote:

....can I ask where you're getting all this information from?

To which information do you refer to?

I'm loking for information myself, have asked now here several times.....nothing.

Any installer who has read this manual would presumably also be, at no fault of his own, none the wiser to the risks you're talking about.

The only correlation I can find is that they advocate a sealed system over a f&e one but give no reason as to why.

A sealed system is a sealed system. Not to be mixed up with an 'open system', one where an unwanted hole is influencing the performance, giving unwanted, unsafe situations.

Use plain logic, the laws of physics :

Imagine a standard condensing boiler installation, the flue pipe and the air supply pipe going through the same hole in the same wall.
As we know a certain air pressure has to be maintained at both openings (inlet/outlet), namely a balanced one.
So no matter how strong the wind blows, the both openings facing the same direction will be exposed to the same air pressure (hekto Pascal). All that the ventilator has to do is to create a negative pressure in the boiler to direct the fluegases out, causing a slight underpressure , just enough to allow for the fluegases to stay long enough in the boiler to cool down at the CH return. Or at the fresh water intake in case of a combi-boiler.

Now we look at the illegal stiuation with the dry condensate trap:

A strong windforce would blow onto the two openings. No problem with a sealed system. The ventilator has no extra work to do since the air pressure on both flue openings is the same. But when there is an opening at the room side, at the condensate trap, the wind would pass through here, taking air or hot flue gases into the room. The air pressure situation in the boiler isn't balanced anymore.
The same goes for the situation when the wind comes from the other side of the house, air would be pushed into the dry or semi-filled condensate trap. The system now being not balanced, the air would take the way of the lowest resistance and blow through both flues, the inlet and outlet.

For these situations the ordinary condensing boilers aren't designed.
The manufacturers state that these boilers are SEALED systems.
And we are not allowed to break this seal.
Hence we have to stick to the laws of physics and to the manufacturer's recommendation. Install a (room) sealed system.

To guarantee a room sealed system we have a condensate trap build-in into the boiler. This 'knee' or 'elbow piece' is the only guarantee for a room sealed installation. Between death and life there are 1.5 inches of water.

May I state from the Vokera installer's manual (model Hydra):
page 25, service parameters

"Parameters 13 and 15, max. fan speed 5500 rounds per minute"

A vital information.

This means the fan's capacity is limited, there is no unlimited volume of air or pressure available.
Open the boiler(disturb the pessure balance by emptying the condensate trap) and this volume/pressure is not guaranteed anymore. The fan can only produce a certain pressure resp. suction.
Imagine someone turns on the kitchen hood extractor (mine makes a stated 800m3, that's per minute !) and the condensate trap is open/empty, gas exit guaranteed. The boiler's ventilator would work like an oar against a ship's propellor. A flame could come out of the half empty trap. Unless other safety parameters kick in and switch-off the boiler.

Look here:

http://boards.ie/vbulletin/showthread.php?t=2056182324

This is a typical scenario of what we're looking at: hot flue gases entering through the condensate trap. All other safety devices have failed.


Another problem are sewer gases. We don't know what they are made from, their composition could change any minute.
Imagine some workshop disposes a flameable solvent into the usually warm sewer. With an empty condensate trap petrol fumes or other ignition-ready gases can be sucked into the running boiler, flash-back guaranteed.

Therefore the boiler manufacturers put-in the water filled trap. Similar to the trap under the sink, behind the toilet bowl. These do usually not burn however. But the boiler does so.

That they don't state what must NOT be done with their boilers is normal, that we don't find these scenarios explained bit for bit.
There are numerous issues that can happen.
All we have to do is to read the manual. If it says "the normal operation is room-sealed " then they have done their duty.
It is up to us to understand the manual, this little but logic sentence. Up to the consumer, the maintenance person, the installer.

We don't read in the car's manual " don't pull a plough with this vehicle " despite there comes a hook at the back with it.
It's plain logic, the manufacturer has done his duty when informing us that a certain resistance (x Newton, kg, tonnes etc.) should not be exceeded. Is the trailor to heavy, is the plough cought up in a rock - not his problem.
It's up to the owner, driver to make sure the vehicel is operated safely.

And the same goes for the boiler. For all technical equipment used in Europe.
I mentioned before that the legal situation might differ in other countries, for example in the USA. There all sorts of absurd scenarios have to mentioned, what NOT to do with a technical device, a product purchased.

heinbloed

One could of course ask why a condensate trap is installed in the first place. Why not running the created condensate straight into the sewer? Why is there this bend?

As Einstein said once: we can not solve problems with the methods they were caused by.
So always ask yourself : Why not? What if I do it the other way?