Boiler Sizing

[desktop987456]

Hello,
I am not in UK so please be gentle!
I have an old heat only boiler 120,000 btu for CH with no DHW installed downstairs and an expansion tank installed upstairs. For DHW we use a separate boiler.

For CH the property has 3 radiators 600x1200 Type 11 and 1 electric convector for a huge lounge 700 sq.ft. installed. All copper piping is 15mm with flow and return.

My gas usage in winter months go as high as 4 HM3 or 15 MMBTU with central heating running for 10 hours daily (5-10 a.m and 4 -9p.m) at 60degC. We are billed in HM3 or MMBTU where I live, I can share my gas usage history from my service provider. The pilot stays on all the time of the boiler. Heat loss in my property is about 10-12kw which I have calculated myself.

Questions I have for knowledgable members are
Does this consumption seem high to you?
Is this boiler oversized for my needs? If yes, should I install a condensing boiler and will my gas usage go down with condensing boiler?
The boiler is about 8 years old and I changed the ciruclation pump last year.
I don't have any TSV's installed on radiators except an old style dial type thermostat on electric convector and I am not sure if it works or not as I haven't seen blower go off ever.
Thanks in advance.

 

[polesapart]

My gas usage in winter months go as high as 4 HM3 or 15 MMBTU

I don't recognise your units. In SI units capitals/lower case letters are not interchangeable.

Please state your annual gas usage for the heating boiler in m³, or for the property if all appliances are on one meter.

A 120 000 BTU (35kW) boiler seems considerably oversized for the system you describe.

 

[desktop987456]

View attachment 280794

 

[desktop987456]

By the way these are monthly figures for the month of December.

 

[gas112]

your boiler is massively oversized those rads are only around 12,000btu`s
Those rads are also massively undersized for the size of that room .
boiler only 8 year old and not condensing already ? condensing boiler rule has been in , in england /wales since 2005

 

[polesapart]

Four million cubic meters in a month?

Implausible, to say the least.

 

[desktop987456]

I know these units are very confusing at least in cubic meters, it should be read as 400 cubic meters instead of 4million!

That is why I had sent the units charged on actual bill which are either cubic hectometer (HM3) or million british thermal units (MMBTU)

 

[desktop987456]

 

[desktop987456]

1 million BTU ( 1 MMBTU) = 26.8 cubic meters ( m³) natural gas.
14.473 x 26.8 = 387 m3.
consumption should be read as 387m3/month which is I think still too high.

 

[desktop987456]

your boiler is massively oversized those rads are only around 12,000btu`s -
Those rads are also massively undersized for the size of that room .
boiler only 8 year old and not condensing already ? condensing boiler rule has been in , in england /wales since 2005

I agree my boiler is oversized
rads do their job of heating the room atleast with this boiler
I am not in England, we don't have regulation here for condensing boilers.

 

[desktop987456]

for reference here is my bill for Sep which just came in without heating. Gas consumption is for stoves (cooking only) about 60m3 for the month.

Personal data deleted at OP request

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