chrisdolley (chrisdolley) wrote,

Logs, Language, Fires and Flues Part Four (Zen and the art of French Fire Design)

The next day we decided to take a long look at the fire. After all, we'd had years of experience with log burning stoves and coal fires. Surely saving this fire would not be beyond us?

It was what the French call an insert, a metal firebox inserted into an existing chimney. As 90% of all heat from an open fire disappears up the chimney, the idea of the insert is to trap some of that heat and channel it back into the room. Most inserts have a heat exchanging mechanism above the firebox to strip the heat and feed it back into the living accommodation.

All very logical.

Except that this one seemed to have a smoke exchanger - it took clean air from the lounge and exchanged it for smoke and toxic fumes.

And I couldn't see how the air was supposed to feed the fire. Most log-burners I'd seen had an adjustable vent at the front designed to feed air into the seat of the fire. It was placed just above the ash layer. After a few days the ash layer would build up and start to block the holes and you'd know it was time to clean out the fire. Nice and simple.

But this insert had no vents. With the fire doors shut the only way I could see air entering was from beneath - through the ash layer. Which didn't make sense. Wood ash was very fine - not the best medium to percolate air through.

And why was the grate so small? It was a sizeable firebox but only the back half was used. The front half was a hinged metal lid which tipped up to reveal a box - presumably an ash box for cleaning. But why have an ash box twice the size of the grate?

And how were you supposed to empty the ash box? Through the hinged lid at the front of the fire? One scoop at a time? Surely not?

We checked the ornamental fire surround again and found one of the bricks was loose. Removing it provided a channel for the ash box to slide out. And with the brick and the ash box removed, air could reach underneath the fire. Was this the beginning of a discovery?

Not quite. Air still had to percolate up through a layer of ash - and what was the point of having an ash box if the fire only worked when it wasn't in place?

Unless the airflow was regulated by the ash box? Like an organ stop?

It still did not entirely ring true but we tried it. We lit fires with every combination of ash box in, ash box out, ash box halfway in; ash box out, brick in. You name it, we watched smoke billow over it.

Perhaps it was the chimney? It had probably been years since it had been cleaned and what better reason for a smoking fire than a dirty chimney?

This sounded like a sensible course of action.

If we could find somewhere to stick the brush.

There was nowhere in the insert. For some reason instead of having one flue it had six. None of them large enough to take a brush. And there was no access hatch in the chimneybreast or in any of the rooms upstairs as we traced the path of the chimney to the roof. The only access had to be from the top, via the chimneypot.

Sometimes you can tell when fate has decided that certain tasks are beyond your reach by the number and level of obstacles that are thrown in your path. Some people take heed and give up. Others ignore the omens and press on.

They are called madmen.

And Shelagh was married to one.

"You're not going on the roof?"

I didn't like the emphasis on the word ‘you're’.

"Why not? We've got the brushes."

"But you?"

There it was again. If anything stronger.

But you don't live with someone for twenty years without knowing how to win the occasional argument.

"We need a fire, agreed?" Incontrovertible logic ploy 37A.

"Ye-es." Playing for time ploy 15B.

"And the only access to the chimney is via the roof."

Silence ploy one to seventeen.

"So, who's going up the ladder?"

Checkmate. When you know your opponent won't set foot on a ladder unless there are at least six men to hold it steady and an ambulance crew on stand-by, you always have the edge with the ladder ploy.

(next instalment: The Pole-vaulter and the Wasp)

Tags: nsa, nsa4
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