Hi,

I have a late 1960's Aga. Born as oil fired. It's been very good, but the boiler has failed. It's a copper box that was strapped to the LHS of the barrel, feeding a large (recently replaced) direct HW cylinder.

It seems the copper heat exchangers / boilers are no longer available. It has to be direct HW suitable - so I believe my choices are

1. Build a new coppper boiler

2. Get a replacement cast 2 part boiler, with vitreous enamel lining

3. Get a stainless boiler made up.

Does anyone have any figures that state the heat transfer capacity of the boilers? Ideally something that compares the different materials. I want to chose the right one.

Aga say 1.1kW for the 90 Gal version & 1.3 kW for the 135 gallon version - but they can't tell me whether this is at min,max or nominal oil flow rates. They also don't say what the start & end temperatures are for the hot water. The factors clearly have a big impact on the output.

I did a simple excel table to get my head round some of the numbers, that might be of interest to some... It does not take efficiency into account - I have no idea what percentage of the heat goes up the chimney. Anyone know?

90 Gal 135 Gal 90 Gal 135 Gal

cc per min,cc per hour,litres kerosene per day, kWh per hour (i.e. kW!),kWh per day, Nominal water heating,Nominal water heating,% going to heating,% going to heating

4 240 5.8 2.35 kW 56 0.73 kW 0.87 kW 31% 37%

5 300 7.2 2.94 kW 71 0.92 kW 1.08 kW 31% 37%

6 360 8.6 3.53 kW 85 1.10 kW 1.30 kW 31% 37%

7 420 10.1 4.12 kW 99 1.28 kW 1.52 kW 31% 37%

8 480 11.5 4.71 kW 113 1.47 kW 1.73 kW 31% 37%

Many thanks.