heat INTO a boiler?

[guydewdney]

If the plumbing meant that hot water got plumbed INTO a boiler, when it wasnt running, how much heat, in a percentage term, would it absorb?

Say it was a 20kw boiler, that means 20kw goes into it, but the gasses / air blowing past the fins makes it absorb that much. Wth it not running, theres no air flow, so would it just heat up, and stay at that temp, and not 'waste' any more heat, or would it all dissapear up the chimney? Its just a lot easier to make my plumbing work this way - so I want to knwo if its worth the extra hassle / expense.

Its a condensing oil boiler, if it makes any differnce.

Guy

[desperate]

Guy, I don't think it would waste anything like 20kW, the gasses/air normally going through the heat ex are at several hundred degrees to transfer that amont of power, IE delta T of 300ish. Whereas working back to front the gasses would only be at 60 same as the water in the exchanger so a minimal delta T, and the fan wont be running, it's gonna be like a small radiator I reckon.

Desp

[Sean]

does the boiler in question allow a free flow of water through it ?

there's usually a demand/diverter/2/3 port valve along the route of most convention systems

[Baz]

with a wbs you can shut off the air vent so stopping most of the airflow but not sure about an oil one. I would think it would be like a small radiator with a fan blowing attached.

[guydewdney]

no air vent closing mechanism - general consensus seems to be "its the same as a small radiator" then? Will test and see what happens.