Boiler feed water is the water pumped into the shell to replace what leaves as steam. It is condensate returned from the plant plus make-up, held in a feed tank, treated, and pushed through a check valve into the boiler. On the Cochran we surveyed the pump, valves, strainer and piping all read 100 °C.
Boilers/Cochran/Feedwater set/This page
Five items carry feed water on the view we surveyed. The feed pump is the largest at 1.49 m². A globe valve isolates the line for maintenance. Return lines bring condensate back from the plant. Feed piping runs the length of the machine in eight sections. A filter and strainer keeps solids out of the pump.
All five read 100 °C on the camera, which is feed-tank temperature. Together they lose 4,713 W over 4.22 m². That is the lowest figure per square metre on the machine, and it is also the surface most often left bare on the grounds that it is only the feed line.
Two blowdown flanges share the same view at 180 °C and have their own page below.
Feed water is treated so the shell does not scale and the water side does not corrode. The controlled quantities are dissolved solids, hardness, alkalinity, dissolved oxygen and pH.
Limits for these are set in BS EN 12953-10 for shell boilers and vary with operating pressure. We did not sample or test the water on the machine we surveyed and quote no figures we did not measure. Numbers for a specific boiler come from its water treatment regime and its examination documentation.
| Element | Temp °C | Area m² | Bare W | Panelled W | Surface °C |
|---|---|---|---|---|---|
| Feed pump | 100 | 1.49 | 1,664 | 87 | 33 |
| Globe valve | 100 | 0.36 | 402 | 21 | 33 |
| Return lines ×3 | 100 | 0.81 | 905 | 48 | 33 |
| Feed piping ×8 | 100 | 1.20 | 1,340 | 70 | 33 |
| Filter / strainer | 100 | 0.36 | 402 | 21 | 33 |
| Total | 4.22 | 4,713 | 247 | ≤45 |
Temperatures are FLIR readings taken on a running boiler. Areas come from the CAD model of the same machine, uplifted for bolts and irregular geometry. Losses are ISO 12241:2022 steady state. The panelled column is capped at the 45 °C touch-safe design target, assessed to EN ISO 13732-1.
At 100 °C the feed line sheds 1,117 W per square metre, a third of what a 190 °C valve sheds.
| Surface °C | W / m² | Area surveyed m² | Where it was read |
|---|---|---|---|
| 100 | 1117 | 1.49 | Cochran feed pump |
| 120 | 1499 | 5.32 | Cochran front door |
| 126 | 1620 | 11.31 | Cochran economiser |
| 130 | 1704 | 5.32 | Cochran end plate |
| 180 | 2888 | 0.90 | Cochran check valve |
Each row is one of our own surveys: the measured loss divided by the CAD area of the same surface. Nothing is interpolated. ISO 12241:2022 steady state, still air, emissivity from the FLIR survey.
Feed water quality is held inside limits set for shell boilers in BS EN 12953-10, and those limits vary with operating pressure. The checks below are the routine ones; the figures they are checked against come from the treatment regime for that machine.
Inzonex did not sample or test the water on the machine surveyed, and quotes no TDS, pH or hardness figures for it. What we measured is the outside of the feed line: five items, 4.22 m², 4,713 W bare and 247 W panelled at 33 °C.
The water pumped into the shell to replace what leaves as steam. It is returned condensate plus make-up, treated before it enters.
A feed tank, a feed pump, a strainer, isolating and check valves, and the piping between them. On the machine we surveyed those come to 4.22 m² of hot surface.
On the Cochran we surveyed the pump, valves, strainer and piping all read 100 °C on the FLIR, which is feed-tank temperature.
They are set in BS EN 12953-10 and vary with operating pressure. We did not sample the water on this machine and quote no figures we did not measure.
On this machine the five feed items lose 4,713 W bare and 247 W panelled. Over 7,700 running hours that is 34 MWh of heat.
| Survey | FLIR S62 Pro, emissivity 0.90, reflected 25 °C, 3 m, full radiometric correction. UK commercial boiler house. |
| Geometry | Rebuilt in CAD from the surveyed machine. Area allowances are stated on the page they are used on and are allowances, not measured areas. |
| Calculation | ISO 12241 steady state. Heat loss is calculated from the measured surface temperature and the modelled area — it is not metered. Full method, basis and limits. |
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