Re-seating the blanking plate in a Morsø stove

I love wood fired stoves. I have one at home and another is on Patience. Both are about twenty years old and have caused little trouble.
But last year we had to replace the flue collar and this year we noticed smoke appearing from the back of the stove. Looking around the back of the stove I could see that a disk or plate had slipped out from the stove body and that was the source of the smoke. But how to fix it?

Blanking cap at back of stove, viewed from above

Metal wood-burning stoves often provide for the flue to come out from the top, back or sides of the stove, so you can choose your configuration according to where you have your outlet.  Here is another stove I know well, with the blanking cap on top, as the flue comes from the back.

Our flue comes from the top, and Morsø have provided a blanking plate in the back to seal up the unused hole. After twenty years of use ours had come adrift - but we weren't sure whether it had been held in place by gravity, flanges, bolts or some other way. And how could we replace it? Would we have to dismantle the stove? And how would that work anyway? Stoves are included in the boat safety check and must be made safe so something must be done.
After a close examination using mirrors and torches in the small gap between stove and wall we resorted to a web search, first of suppliers, then of forums. And this is what we found:
The plate could easily be removed without damage. We inserted an old screwdriver into the gap and gently levered it out.

Inner face of blanking cap, before cleaning up. Note lug on the left and remains of lug on the right.

The plate had been held in place by two lugs screwed to the inner edge of the plate. This made them inaccessible from the outside.
The body of the stove was in satisfactory condition but there was debris, black and gritty, inside the hole and around the edges.

We also found that gaining access to the inside of the hole from the front of the stove was prevented by the baffle, a metal shield which directs smoke up the chimney (and prevents flames going up). Some people say you can remove the baffle to get access to the hole but we found it was very firmly held in place. If you can remove the baffle you'll be able to fit a new plate with lugs. That is the best answer. But we couldn't remove the baffle so ....

Stove from the front, grate removed. The baffle is a false back to the stove with a sloping internal roof

... here's our solution to the problem. This is what we did:
1. Remove the plate, as above, gently levering it off if it hasn't already fallen out.
2. Clean the plate and the rim of the hole with a wire brush, especially the edges.
3. Remove as much of the debris from inside the hole as you can and dispose of it. You may find the broken lug(s)! Test to see that the cleaned plate fits neatly into the hole. You might have to cut away any remains of a lug.
4. Buy some fire cement.
5. Brush a little water onto the edge of the plate and the edge of the hole.
6. With a spatula, press a layer of fire cement all around the edge and outer surface of the hole.
7. Place the plate neatly and firmly into the hole. Push firmly. With a small hammer and a short length of timber you should be able to tap the plate firmly so that it is almost flat to the back of the stove. Don't hammer the stove or the plate directly. Remove any cement that has squeezed out and check there are no visible gaps.

And that's it! Let the cement dry according to the instructions on the pack. Take the opportunity to clean the rest of the stove and to tidy your log pile. Check carefully that the plate remains in place and that no more smoke comes from the stove back. Check this as part of normal maintenance: it's a health and safety issue. Continued heat may cause the fire cement to crumble and it will need replacement - though now you know how to do it that's not a problem.
If your blanking plate is damaged or warped you can buy a replacement from any Morsø supplier. Measure your blanking plate and make sure you know the correct model of stove.
Finally, my sweep tells me that we should have fire bricks to deflect the heat from the rear and sides of the stove.  This is true of steel stoves as well as cast iron. A couple of fire bricks would protect the blanking cap and would protect the sides against direct heat.
In extreme cases, he says, he has drilled into the blanking cap and inserted a stainless steel threaded rod then wound a metal bar so it lies across the rear of the stove, holding the cap in place. Too difficult for me, but I think the fire brick is a useful and important addition.
Which is better, steel or cast iron? It's explained here at StoveWorld. 

Replacing the flue collar on a Morsø Squirrel

The Morsø Squirrel range of solid fuel stoves is probably the most popular for narrow boaters. It's compact, gives off the right amount of heat for a cold metal boat of 40-50 feet long and has few things that can go wrong.
Ours, however is 20 years old and starting to show its age. This picture shows the stove in situ ...

... and closer inspection shows the collar that joins the flue to the stove is in bad shape.

I had filled the gap with fire cement but this may have made it worse by restricting natural expansion and now the collar has broken into three parts.
As a stove potentially gives off poisonous carbon monoxide this is Not A Good Thing, so we planned to fix it.
The first thing needed was a flue collar

and the lugs and screws for fitting it. I bought ours from Bowland Stoves which is the parent group for Morsø.
First we examined the top of the flue because we were unsure how that was fitted and it would be necessary to raise the flue a few inches to insert the new collar. As it turned out we need not have worried, as it was held in place by packing, insulation and mastic rather than troublesome bolts. It should be able to simply slide up if the packing is loosened so there was no need to unscrew the circular panel around the flue, which appears to be there to tidy up the edges of the ceiling panels.

You can see how the flue disappears into the cast iron chimney collar (that's the one that emerges outside the roof of the boat) and the fire rope packs it in place.
We were now able to knock away the broken old flue collar and its fire cement, revealing the bottom of the flue where it joins the stove.

Now it becomes clear that there is a simple hole in the top of the stove, which we cleaned up with a wire brush. We also found that there was a baffle inside the stove - created to direct the hot gases - but which had accumulated 20 years of non-combustible material on its top surface. This was cleared out from inside the stove before going any further.
The collar has two tabs and by inserting the two screws and screwing loosely to the two lugs we were then able to lift up the flue a couple of inches and slide in the collar with its screws and lugs in place. This took two of us - one to lift the flue and the other to slide in the collar.

This closer view shows the collar in place with the screws visible. Before the flue was put back into place the lugs were placed under the top surface of the stove and the screws tightened to hold the collar firmly in place. Note that there is a long end and a short end to the lugs and it's the long end that should be placed under the edge of the hole. So the screws hold a sandwich with the lugs at the bottom, the stove top next and the collar tabs at the top. A clean surface to the edge of the hole in the top of the stove ensures a good seal.
Finally, the bottom of the flue was placed firmly back in the centre of the collar, the small gap between flue and collar packed with fire rope and we ensured the top of the flue was seated neatly into the chimney collar, packed firmly and made waterproof from the outside with mastic.
All in all this took us a bit over an hour and the biggest problem was washing our hands and arms of soot! We will, however, monitor the gases from the stove with our CO sensor as no risks should be taken with gas and stoves.

I strongly recommend the pdf file "Installing Stoves in Boats" by SOLIFTEC.
See also the Boat Safety Scheme Advice.
And Morsø's own installation guide.
See also our blog entry on re-seating the blanking plate on a Morsø stove.