Real world vs theoretical hot water temperatures

[Steelmasons]

37 kW would net around 60 litres minute @ 70c temp rise.

 

[TCCHeating]

Has anybody compared the theoretical hot water temps to what you actually get in the real world?

Yes. Every time a I go to repair a boiler where customer is saying hot water is not hot enough

I've just done the comparison on my Ecotec plus 824. I'm getting a 42 degree rise at 8 litres per minute when the theory says it should be achieving 43 degree rise so it's pretty close

Great.

 

[jakeycrx85]

37 kW would net around 60 litres minute @ 70c temp rise.

Very amusing. They're a 35 degree rise at 15.2 l/min.

How can you say my flow rate is poor without knowing my incoming water pressure?

Yes. Every time a I go to repair a boiler where customer is saying hot water is not hot enough


Great.

Another clown joins the thread.

 

[roguetrader]

How are you measuring your temperatures?

 

[roguetrader]

Hope that's not too sarcastic

 

[AGAS]

How are you measuring your temperatures?

+1

 

[jakeycrx85]

How are you measuring your temperatures?

With the thermocouple on my Fluke.

 

[roguetrader]

So could easily be a degree or two out.

 

[AGAS]

op why are you worried about a degree ? don't say your not or else you would not of posted it . if your worried then fair enough fair play for asking the question

 

[jakeycrx85]

So could easily be a degree or two out.

Yes of course as it's not calibrated. You can buy them calibrated though and they are normally pretty accurate. Fluke specify an accuracy of +/- 1.1 degrees.

It could have a zero error but it will still measure the temp rise accurately. I'm not interested in the actual temps only the difference between the 2.

 

[jakeycrx85]

op why are you worried about a degree ? don't say your not or else you would not of posted it . if your worried then fair enough fair play for asking the question

1 degree on a 7/8 year old boiler that hasn't been serviced for a while seems pretty good IMO so I'm not worried. The reason for posting was to make a comparison to the results other people have seen. It appears so far that nobody seems to do it though.

 

[roguetrader]

So we are 1 degree out, which may or may not be down to your measuring instrument.
Let me get my slide rule and scientific calculator out and try and see where it's all gone wrong.

 

[TCCHeating]

It appears so far that nobody seems to do it though

Yes we do. As I said previously.

Remember? You called me a clown for posting it.....

 

[Steelmasons]

Have you carried out a gas rate?
I wonder if the weir cup you are using is worn.

 

[jakeycrx85]

So we are 1 degree out, which may or may not be down to your measuring instrument.
Let me get my slide rule and scientific calculator out and try and see where it's all gone wrong.

You're really don't get it done you. Most instruments tend to go out on their zero but maintain their linear scaling.

For example my thermocouple could have a zero error of -1. It would read -1 degrees at 0 degrees and 99 degrees at 100 degrees.

It could also have a zero error of +1. You just end up with an offset. Both of these thermocouples would still measure the temperature rise just fine because I am only interested in the difference between my incoming water and my DHW. The actual temp readings are irrelevant.

 

[jakeycrx85]

It appears so far that nobody seems to do it though

Yes we do. As I did previously.

Remember? You called me a clown for posting it.....

No you haven't. What results have you seen on a 24kw boiler? Or any boiler.