need advice on fitting combi boiler

[monoxide62]

Way I see it most houses , have legoinella bugs floating around some where ( maybe ?)

Your always sittin on that fence Transam.

 

[bengasman]

Been in the trade for 35 years & NEVER come across this...

Off course not; a legionella victim needs either a doctor or a corroner to check him out, not a plumber.
Legionaires disease numbers are verifiable to anyone who cares to look at ONS archives.

most open vented cylinders were heated via gravity fed primaries where water was heated to a minimum of 70K with hot water being drawn off every day.

According to my information from ACS training, fully pumped became the standard about half a century ago.
Apart from that, to heat gravity fed cylinder to remain above 65C, the boilerstat would have to be on or very near max. Any RGI worth his keep has the experienced most boilerstats NOT to be at max.

 

[bengasman]

Way I see it most houses , have legoinella bugs floating around some where ( maybe ?)

Probably do, but is irrelevant. Legionella only becomes a threat above certain levels apparently.

 

[monoxide62]

Been in the trade for 35 years & NEVER come across this...

Off course not; a legionella victim needs either a doctor or a corroner to check him out, not a plumber.
Legionaires disease numbers are verifiable to anyone who cares to look at ONS archives.

most open vented cylinders were heated via gravity fed primaries where water was heated to a minimum of 70K with hot water being drawn off every day.

According to my information from ACS training, fully pumped became the standard about half a century ago.
Apart from that, to heat gravity fed cylinder to remain above 65C, the boilerstat would have to be on or very near max. Any RGI worth his keep has the experienced most boilerstats NOT to be at max.

Take it from me gravity fed hot water cylinders were heated to above 70k , minimum boiler stat temp was 65K & most housholds set the stat to around #3 which was 'around' 75K , boiler stat max temp was in the region of 82k although most calibrated to around 90K ...........think about this , most hot water cylinders with hot water temperature control (cyl stat) are set to around 65K , the old gravity system would have hot water temperatures in excess of 70K , so which is better regards killing the bacteria that legionella thrives on , 65K or 75K?

 

[bengasman]

Never looked into the details about those temperatures, but at a guess I'd say that both 65K and 75K will kill legionalla stone dead in seconds.

Something tells me that you are trying to be a bit too clever with the figures you quoted.

 

[monoxide62]

Never looked into the details about those temperatures, but at a guess I'd say that both 65K and 75K will kill legionalla stone dead in seconds.

Something tells me that you are trying to be a bit too clever with the figures you quoted.

I used to calibrate boiler stats when sub contracting for Islington council (1980)

Ideal temp for legionella bacterium is about 37K , below 20K & above 55K the bacterium is dormant , as you can see hot water heated by gravitys will never fall below 60k due to minimum temp @ boiler stat (back end corosion being the issue) , this is not the case when hot water is controlled via cyl stat , i've seen these set as low as 50K , borderline temps being the case for legionella.

 

[bengasman]

I used to calibrate boiler stats when sub contracting for Islington council (1980)

Subcontracting for CALIBRATING boiler stats on council stock???? First time I ever heard of council spending money on that. In fact, I've never heard of open vent boiler stats being calibrated period.

But even if, since when is social housing heating work known for it's great standards? Did a brief stint assesing in social housing, and I don't think a day went buy where I didn't cut somebody off due to immediately dangerous situation.

Ideal temp for legionella bacterium is about 37K , below 20K & above 55K the bacterium is dormant

You are miles off. Like I said: you are trying to be a bit too clever.

 

[gasafengineer]

 

[bengasman]

I stand by my figures regards legionella , i don't have to be cleaver , & your figures are?

I am pretty sure that below 55K legionella is stone dead, and certainly below 20K.

Not that it matters; when your cylinder goes below 20K, legionella is the least of your worries.

 

[monoxide62]

I used to calibrate boiler stats when sub contracting for Islington council (1980)

Subcontracting for CALIBRATING boiler stats on council stock???? First time I ever heard of council spending money on that. In fact, I've never heard of open vent boiler stats being calibrated period.

But even if, since when is social housing heating work known for it's great standards? Did a brief stint assesing in social housing, and I don't think a day went buy where I didn't cut somebody off due to immediately dangerous situation.

Ideal temp for legionella bacterium is about 37K , below 20K & above 55K the bacterium is dormant

You are miles off. Like I said: you are trying to be a bit too clever.

Whenever we installed the boilers we had to calibrate the stats , simples , nothing clever in my postings , those who think it's clever are the ones who don't know.

 

[transam]

Way I see it most houses , have legoinella bugs floating around some where ( maybe ?)

Your always sittin on that fence Transam.

Best place to be , providing it's not to high

 

[Gasman77]

I have a 37cdi which gives a great shower, for as long as I want. However, it is slower than the old OV cylinder at filling my bath.
Still waiting ben....

If you insist.....

( Decent ) combi will fill a bath just as surely as a cylinder, just a bit slower. Bearing in mind that nobody in his right mind is standing next to the batch waiting til it's full whilst twiddling his thumbs, it makes no difference whether it takes 4 or 8 minutes.
What combi offers that ov cylinder doesn't is:
2nd, 3rd and 4th bath even if you forget turning the timer on.
Legionella-free water; contaminated cylinder water used to be #1 source of legionaires disease when we still all had open vents.

So the statement was correct then, a combi is better for a shower, not as good for filling a bath.

Do you want some salt and vinegar to go with that chip?

 

[namsag]

My bath is 240 litres and my combi fills it quite easily...After its heated the water in the cylinder attached

I like the way people say a combi can fill 4 or more baths in a row without running out yep they can but in the winter it would leave the house quite cold with no heating during that time

 

[Agile]

I am pretty sure that below 55K legionella is stone dead, and certainly below 20K.

I think that at either of those cryogenic temperatures the legionella would be well frozen !

 

[ChrisOxford]

You were thinking what I was thinking