update for r2d2,water sys and jimbo

He did water systems.

2m³ in 50mins

 

water sys what about the 2 cu mtr to heat the water (150 l) it seems excessive?

Its about right.

 

He did water systems.

2m³ in 50mins

If a Powermax took 50 mins to raise 150 litres 60C, it is way too slow. There is something wrong with the boiler settings. Is the meter regulator at fault? Only allowing a reduced volume of gas.

The boiler settings and the gas meter and its regulator needs looking at.

 

He did water systems.

2m³ in 50mins

If a Powermax took 50 mins to raise 150 litres 60C,
it is way too slow. There is something wrong with
the boiler settings. Is the meter regulator at
fault? Only allowing a reduced volume of gas.

The boiler settings and the gas meter and its
regulator needs looking at.

Some calcs:

To raise 150 litres water 50C over 50 mins = 17.50 kW

That is output. Assume 85% effciency of boiler then the input is: 20.59 kW

<u>Bang on!!!!!</u> 21 kW <u>The boiler is OK.</u>

 

He did water systems.

2m³ in 50mins

If a Powermax took 50 mins to raise 150 litres
60C,
it is way too slow. There is something wrong with
the boiler settings. Is the meter regulator at
fault? Only allowing a reduced volume of gas.

The boiler settings and the gas meter and its
regulator needs looking at.

Some calcs:

To raise 150 litres water 50C over 50 mins = 17.50
kW

That is output. Assume 85% effciency of boiler then
the input is: 20.59 kW

<u>Bang on!!!!!</u> 21 kW <u>The boiler is OK.</u>

There again if the boiler is capable of more output than 21kW, the modulation may have brought back the boiler output as the temp diff of the flow and return closed.

This still doesn't sound too right as 50 mins to recover the DHW is way too long, as the CH will be starved during this time as it is a priority system.

Mmmm, still needs checking, both boiler and meter regulator.

 

To raise 150 litres water 50C over 50 mins = 17.50 kW

150 x 4.18 x 50 = 31350 kj.

divided by 3000 seconds =10.45 kw.

Then add on boiler and heat exchanger inefficiencys.

 

To raise 150 litres water 50C over 50 mins = 17.50
kW

150 x 4.18 x 50 = 31350 kj.

divided by 3000 seconds =10.45 kw.

Then add on boiler and heat exchanger inefficiencys.

You are right. I put 250m litres not 150 litres.

Simpler using
(temp rise x litres x specific heat)/ seconds in an hour

(50 x 150 x 4.2)/3600

 

To raise 150 litres water 50C over 50 mins = 17.50
kW

150 x 4.18 x 50 = 31350 kj.

divided by 3000 seconds =10.45 kw.

Then add on boiler and heat exchanger inefficiencys.

So how come it took 21 Kw

 

So how come it took 21 Kw

Ineficiencys through the heat exchangers ?

unit charge (pence per kWh) 1.63 .

So it cost about 34 pence to heat this volume of water.

 

1.63p per Kw :O where do you get your gas from, my last bill was 4.42 :'(

 

What your saying is everything so far has been a waste of our time.

Thank you very much and goodbye

 

Why would you suppose we ask questions.

Information needs to be actual and accurate not guesswork.

 

sorry i didnt look at the burner all the time during
the 1 hour test - except for the last 10 mins the
burner wasnt on then

Time heating the cylidner from cold. Approx temp of cylidner at statr and finsih and how much gas used. That will give a good insication of the boioer and meter accuracy.

If they are fine you have serious problems in insulation on the CH side. Or, you have a very big house.

 

The 50mins to raise the temperature through 60c and the 2m³ (21Kw) of gas is actual give or take a few degs C Water Systems.

Water Systems;

In hot water priority, does the boiler remain on high flame untill the store is satisfied or does it modulate down and trickle charge say the last 10-20c.<u></u>

 

1.63p per Kw where do you get your gas from, my last bill was 4.42

I may have been mistaken here. It was pheonix gas pdf link which I think was a couple of years old.

so its £2k per year - **** me !!!!

Sounds fine to me. My heating bill for oil is around £1000 yearly in a property half the size of yours and as I have said I know people paying a lot more than you are paying heating propertys fitted with UF heating.

In hot water priority, does the boiler remain on high flame untill the store is satisfied or does it modulate down and trickle charge say the last 10-20c.

It will depend on the size of the coil inside the cylinder. On initial start up the burner should modulate up full but as the cylinder heats up the coil may not be able to dissipate the heat that the boiler is producing so it will either modulate back the burner or switch off with the pump remaining running.
In my view that is .