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Discuss Condensing Boilers - what volume of codensate is discharged in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Rob Foster

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When a 25 kw condensing boiler is going full tilt in the winter what volume of condensate water might be discharged per hour ? Obviously an overflow pipe will cope. Anybody any ideas. It could be 20KW or 30 KW I am looking for a ball park volume. Many thanks
 
What's the reason you need to know?
I don't think many boiler are condensing 100% of the time
 
Would say under a litre an hour
 
Types of work ....1 Contract ch installation new build, 2 medi-gas contracting, 3 local plumbing/domestic ch installs but in a quite tight area - no adverts just word of mouth so we knew the customer and they us. 1st 2 profit is all down to margins and speed 3 is down to reputation word of mouth. Beware you have to get from one man (you) to over 5/6 very quickly or you end up not earning anything yourself Young men for 1, steady fellas for 3 and anybody who was prepared to work xmas easter and bank holiday for 2
 
Hi fixitflav thanks for that - how did you calculate it may I ask - in awe of you on this one
Originally I used a hand calculator and seem to have dropped a cod, it's actually more like 3.8 l/h.
Calculation below. I used Mathcad, but pleasantly surprised it copied in OK. Don't worry about apparent lack of conversion factors etc, Mathcad takes care of that for you. I've made one or 2 assumptions, as natural gas is not pure methane, but it won't be far out for water produced. Be interesting to compare with maker's figure, to get an idea about what fraction condenses. Come back if you need more.

upload_2018-8-7_19-17-40.png
 
Originally I used a hand calculator and seem to have dropped a cod, it's actually more like 3.8 l/h.
Calculation below. I used Mathcad, but pleasantly surprised it copied in OK. Don't worry about apparent lack of conversion factors etc, Mathcad takes care of that for you. I've made one or 2 assumptions, as natural gas is not pure methane, but it won't be far out for water produced. Be interesting to compare with maker's figure, to get an idea about what fraction condenses. Come back if you need more.

View attachment 34144

2.347m3/hr not 2.429

also that figure is a constant 25kw on a heat/system boiler which even at the middle of winter wont run constantly on full

if its a combi that figure will be lower also due to the output
 
Depends on the makeup of the gas and the assumed boiler efficiency, but either is near enough in practice.

OP said "when the boiler is going full tilt".

Yes but I would be surprised if it went for longer than 30 mins on full tilt will modulate down to half power

Also return temp matters a lot
 
Rob, when you had 20 fitters working for you what sort of work were you doing?
Rob, when you had 20 fitters working for you what sort of work were you doing?
I did not mean to end up with 20 or so. I had semi retired at 40 ish , myself and 2 others did really well in the late 80's + 90's building and property. I was stood in a pub ! fella next to me was doin xword and asked whats a greek cheese ? conversation ended with him asking me to help him with a ch installation next day. When we did it he was impressed and asked how much I wanted - I told him - Jimbo said he didnt earn that rate himself. So it ended up with me getting the work for him and about a score of his really experienced older pals at my idea of rates - it worked. wacky story but all true
 
Yes but I would be surprised if it went for longer than 30 mins on full tilt will modulate down to half power
So would I, but my calc is for an instantaneous rate. Reminds me of introduction to rates of change and differential calculus a few (!) years ago. Sir told a tale of a woman being stopped by a cop and told she was doing 45mph. Don't be silly, officer, she said, I only bought the car 10 minutes ago.
Just out of curiosity, how do you get 2.347m3/hr in #12?
 
So would I, but my calc is for an instantaneous rate. Reminds me of introduction to rates of change and differential calculus a few (!) years ago. Sir told a tale of a woman being stopped by a cop and told she was doing 45mph. Don't be silly, officer, she said, I only bought the car 10 minutes ago.
Just out of curiosity, how do you get 2.347m3/hr in #12?

25/10.65
 

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