100KW gas boiler for domestic install!

[infromthecold]

Hi All

New member and first post.

I'm not in the trade so hoping folks on here with all the knowledge can assist.

Got 5 bed detached Victorian house that has no central heating so in process of getting boiler and rads spec'd.

Have been told that will need a 100kw boiler and that this boiler will need a a larger gas supply pipe even though there is 22mm already.
Was hoping for a combi as there is only one bathroom with shower over bath.
Room sizes (in metres) are listed below, All double glazed with solid walls but I calculate heat requirement at 25KW so where the 100KW comes from I have no idea hence this post. All the on-line calculators I have used are all coming in around 25 - 26 KW for heating.

Hope someone can help or offer advice. I would think 100KW is large enough for a school or factory or a 5 bed with 14/15 rads.

Cheers

Room H, W, D
Living Room 3.1, 5.49, 4.88
Sitting Room 3.1, 4.22, 3.91
Dining Room 3.1, 3.23, 3.12
Kitchen 3.1, 5.18, 4.47
Bed 1 3.1, 4.42, 3.2
Bed 2 3.1, 4.42, 2.29
Bed 3 3.1, 7.21, 3.56
Bed 4 3.1, 3.86, 3.23
Bed 5 3.1, 4.27, 4.11
Bath 3.1, 4.42, 3

 

[TBServices]

Most will add 10% to each rad/room when sizing rads, which explains the discrepancy you've found.

Again, get a new engineer!

 

[kevbat]

quality work josh

 

[Fishpond]

Worked out what house requires previously and size, volume and construction need 32kw. Rads output 34kw.

Worcester TSM has been to house today to talk to engineer and he has said it needs a 65KW boiler and a U16. I am trying to get the contact details for the worcester TSM so he can explain his thinking.

A 40CDI should be fine. I recently fitted a 40CDI regular on a house with 31 rads. The whole house heating calc came to just over 37KW and it works perfectly well and is in no way undersized from an output perspective!

I don't think you need a light commercial boiler for what you have... 40KW domestic is fine

 

[vern]

Absolute horse sh 1 t if you need 65 kw you have a swimming pool to heat also, I specialise in larger properties and from the info you have given no way!

 

[snowhead]

I bet even B & Q's calculator comes up with a total for a boiler size they stock;

B&Q Online: From Kitchens & Bathrooms to Sheds & Paving; plus planning tools

 

[doitmyself]

Worked out what house requires previously and size, volume and construction need 32kw. Rads output 34kw.

Earlier you said that you had used several online calculators and could only get to approx 25kW. Which one did you use to get the 32kW?

 

[Howsie]

Four pages in and we're still nowhere.

/exits stage left.

 

[infromthecold]

Earlier you said that you had used several online calculators and could only get to approx 25kW. Which one did you use to get the 32kW?

Used whole house boiler sizing method which came out at 23kw Calculated Boiler Size

Used heat loss calculator to work out how much power required for each room and that came out at 23KW Trademate by City Plumbing Supplies

I also used [DLMURL="http://www.theradiatorcompany.co.uk/heatoutput/"]Radiator Heat Output Calculator and size calculator - The Radiator Company UK[/DLMURL] to see what radiator output was required for each room. Got the output for each room, added up and total was 24KW

Not sure if needed to add 2KW for HW so have added just in case which brings it up to 25-26KW

The 34 KW figure comes from using the radiator manufacturers technical data. I have looked up the output of each rad installed and the total out of all rads is 34KW.

Head spinning now :-( Have asked another installer to come to house and take a look.

 

[TBServices]

Four pages in and we're still nowhere.

/exits stage left.

Totally pointless thread now

 

[Centralheatking]

In from cold has keen confused - 100,00 btu not 100KW 30 kw will do his place
on a system boiler set up. 100kw will light up over 1600 60 watt light bulbs
- old type !!!!!!!!!! or 100 1 bar lecky fires

Hi All

New member and first post.

I'm not in the trade so hoping folks on here with all the knowledge can assist.

Got 5 bed detached Victorian house that has no central heating so in process of getting boiler and rads spec'd.

Have been told that will need a 100kw boiler and that this boiler will need a a larger gas supply pipe even though there is 22mm already.
Was hoping for a combi as there is only one bathroom with shower over bath.
Room sizes (in metres) are listed below, All double glazed with solid walls but I calculate heat requirement at 25KW so where the 100KW comes from I have no idea hence this post. All the on-line calculators I have used are all coming in around 25 - 26 KW for heating.

Hope someone can help or offer advice. I would think 100KW is large enough for a school or factory or a 5 bed with 14/15 rads.

Cheers

Room H, W, D
Living Room 3.1, 5.49, 4.88
Sitting Room 3.1, 4.22, 3.91
Dining Room 3.1, 3.23, 3.12
Kitchen 3.1, 5.18, 4.47
Bed 1 3.1, 4.42, 3.2
Bed 2 3.1, 4.42, 2.29
Bed 3 3.1, 7.21, 3.56
Bed 4 3.1, 3.86, 3.23
Bed 5 3.1, 4.27, 4.11
Bath 3.1, 4.42, 3

 

[infromthecold]

In from cold has keen confused - 100,00 btu not 100KW 30 kw will do his place
on a system boiler set up. 100kw will light up over 1600 60 watt light bulbs
- old type !!!!!!!!!! or 100 1 bar lecky fires

Hi
That's exactly what I thought but installer and now worcester TSM have said that not the case. So, with all the advice from everyone on here and my initial concerns I have another instaler scheduled to survey.
I am amazed that a representative of the manufacturer can give such poor advice :-(

 

[doitmyself]

Used whole house boiler sizing method which came out at 23kw

You said earlier that you were considering a combi boiler as you had only one bathroom/shower. Is this still the case?

If it is, the size of boiler is really determined by the hot water requirement, which depends on the maximum incoming cold water flow rate. You can easily check this at the kitchen sink cold tap using a bucket marked in litres and a watch with a second hand. Time how long it takes to fill to the top mark (usually 10 litres); then convert this to litres per minute. The required Hot Water output of the boiler is at least 2.5kW per litre/minute; i.e a flow of 10 litres per min will require a 25kW HW output.

You can ignore the 2kW allowance for HW if you have a combi boiler.

As for the advisability of having a combi boiler, don't forget that all taps, hot and cold, as well as washing machines, dishwashers etc are fed from the one source: the incoming cold main. So there could well be a reduced flow rate if more than one tap etc is in use at the same time. If you have a garden tap, you can do a basic test to see what the effect will be. Repeat the flow test, but this time with the garden tap full open. You will then find the reduction in flow rate.

 

[M77]

Would a 100kw boiler even modulate down to 32kw?

 

[Centralheatking]

so you could thank us all talk to the organ grinders not the monkeys

Hi
That's exactly what I thought but installer and now worcester TSM have said that not the case. So, with all the advice from everyone on here and my initial concerns I have another instaler scheduled to survey.
I am amazed that a representative of the manufacturer can give such poor advice :-(

 

[infromthecold]

so you could thank us all talk to the organ grinders not the monkeys

Many thanks go to all who have participated on this thread.
Without professionals like yourselves willing to share your knowledge and experience folk like me are in the dark.

Many thanks once again for everyone's help.