Leaky Squirrel!

[Richardcn]

Hi All

 

We're looking for some advice.

(Apologies, in advance, for the long post)

 

Before the heating season last year I refurbished our fireplace, replaced the flue and also did the glass and door seals on our Morso Squirrel 1410. However, we have a really frustrating problem now with what appears to be a small carbon monoxide leak. Annoyingly it only happens under very specific circumstances and as yet I cannot find the source.

 

The stove was completely emptied and doors removed before it was VERY  carefully moved a few feet away in order to access the fireplace, then equally carefully put back on the new hearth and bolted down with new brackets. A new stove collar, reducer & flue were then installed ensuring careful alignment, appropriate stove rope was used and it was all carefully sealed with high temp silicon (the PROPER high temp stuff). Before refitting I cleaned & examined the stove for cracks and then started blacking before the cold beat me. All seemed well, apart from the awful blacking smell but from time to time we'd notice the CO monitor closest to the stove would have a low reading (circa 20ppm). As we had some problems with our gas grill emitting CO (since fixed) we put it down to that and though nothing of it until a couple of weeks ago. We went away for 3 days leaving the fire well stacked and on a low setting, as we've often done over the years. However, on return the two CO alarms in the living area were screaming and reading circa 70ppm!

 

We were astonished (and the cat was none to pleased 🥺) as the boat had been visited 24hrs earlier with no reports of any issue and by that time (approx 36hrs after departure) the stove would have been almost cold. Somehow during the remaining 24hrs before our return the alarms were triggered!

 

Since then, having not discovered any obvious reason for the alarms, I've been troubleshooting, so far with no success. I've discounted Hydrogen from the batteries giving a false positive and also any new cracks or failed sealing on the flue and I've replaced the main door seal just in case but we still have the same problem. However, the problem ONLY arises when the fire is low mid morning onwards (whether by deliberate reduction of the air inlets or by lack of fuel) until whenever I stoke the fire to add warmth. Obviously we ventilate to zero the reading but once the fire is up to temp there will be no CO reading until the next time the fire is low the next day (if it's a mild day). We never find a positive reading in the night (I always check) and never find one in the morning even though with all the unseasonably mild weather the stove has been set to minimum air on the vents (top & bottom open half a turn), anything less and I risk it going out!

 

My best guess is that we have a small leak from between two of the panels and that when the stove is hot it is drawing air in and when cool(er) then CO is leaking out.

Has anybody had a similar problem or can suggest what might be the cause and how best to troubleshoot? I have brought a new CO monitor with the same results.

 

Regards

Richard

 

Edited March 7 by Richardcn

[Jen-in-Wellies]

Smoke pellet lit inside, with fire out and vents in similar state to when left in overnight? Should show up where the CO is escaping.

What about neighbouring boats? Stove smoke, or generator fumes getting in to yours under certain wind directions/speeds? 

[matty40s]

Check the plate on the rear of the stove, the one used if the flue exits out of the back, not the top. This is a common fail point, as it is difficult to see or get to. The two retaining lugs can break, and the seal can deteriorate, either could lead to escaping CO if the flue is cool as you describe.

[ditchcrawler]

2 minutes ago, matty40s said:

Check the plate on the rear of the stove, the one used if the flue exits out of the back, not the top. This is a common fail point, as it is difficult to see or get to. The two retaining lugs can break, and the seal can deteriorate, either could lead to escaping CO if the flue is cool as you describe.

Had that happen, noticed the flickering reflecting on the tiles 

[Richardcn]

32 minutes ago, matty40s said:

Check the plate on the rear of the stove, the one used if the flue exits out of the back, not the top. This is a common fail point, as it is difficult to see or get to. The two retaining lugs can break, and the seal can deteriorate, either could lead to escaping CO if the flue is cool as you describe.

Ah that's good info. I'll take a closer look as soon as the stove is cooler. Thank you.

[blackrose]

3 hours ago, Richardcn said:

 appropriate stove rope was used and it was all carefully sealed with high temp silicon (the PROPER high temp stuff). 

 

How long have you used the stove since you refurbished it? If you used the 1200C Envirograf stuff to seal the flue into the stove collar ideally it should have been left for 24 hours to go off but it would still have released a horrible smell and blue fumes when you got the stove going. I'm just wondering if it hasn't fully cured and it's those fumes that are triggering the CO alarm?

 

If you only used the 300C Plumbaflue stuff I'd suspect that might be the problem. It's fine for sealing the flue into the roof collar at the top but I wouldn't use it anywhere near the stove itself. I know others will say they've done it but why use an inferior product when a much better one is available for a few quid more?

Edited March 7 by blackrose

[Richardcn]

3 hours ago, Jen-in-Wellies said:

Smoke pellet lit inside, with fire out and vents in similar state to when left in overnight? Should show up where the CO is escaping.

What about neighbouring boats? Stove smoke, or generator fumes getting in to yours under certain wind directions/speeds? 

I'll consider this if all else fails but I wonder if such a small leak would reveal itself unless I close off almost all other orifices?

22 minutes ago, blackrose said:

 

How long have you used the stove since you refurbished it? If you used the 1200C Envirograf stuff to seal the flue into the stove collar ideally it should have been left for 24 hours to go off but it would still have released a horrible smell and blue fumes when you got the stove going. I'm just wondering if it hasn't fully cured and it's those fumes that are triggering the CO alarm?

 

If you only used the 300C Plumbaflue stuff I'd suspect that might be the problem. It's fine for sealing the flue into the roof collar at the top but I wouldn't use it anywhere near the stove itself. I know others will say they've done it but why use an inferior product when a much better one is available for a few quid more?

Envirograf on all the joints as my experience with using cement was that it was not fit for this particular purpose. The previous reducing collar cracked due to this, I believe. It was applied in stages to ensure proper curing and given more than the stated time as I didn't want to be coming back to redo it any time soon. We're approx 5 months post refurb now.

2 hours ago, ditchcrawler said:

Had that happen, noticed the flickering reflecting on the tiles 

Bet that was a bit of a shock! Ours seemed solid when I checked it but I did add a bead of Envirograf just in case. Of course, nothing lasts forever (not even National Insurance apparently 😆).

[BEngo]

Have  you checked that the inside of the stove is clean, particularly below the top flue inlet and behind the back boiler or on top of the baffle plate?

 

CO production soars if the fuel is damp.

 

If the stove was  OK CO wise 36 hours after filling, then something has changed after that.

 

  I would  expect the stove to be out and cold by then,  (mine struggles to go for  much over 24 hours) as it seems  you did.  A stove  that is out does not produce CO. I would be inclined to look again for  possible other sources of CO or gases that trigger CO alarms.  Is the alarm OK- does it pass the joss stick check?

 

N

 

[Richardcn]

1 minute ago, BEngo said:

Have  you checked that the inside of the stove is clean, particularly below the top flue inlet and behind the back boiler or on top of the baffle plate?

 

CO production soars if the fuel is damp.

 

If the stove was  OK CO wise 36 hours after filling, then something has changed after that.

 

  I would  expect the stove to be out and cold by then,  (mine struggles to go for  much over 24 hours) as it seems  you did.  A stove  that is out does not produce CO. I would be inclined to look again for  possible other sources of CO or gases that trigger CO alarms.  Is the alarm OK- does it pass the joss stick check?

 

N

 

Yes I clean and vacuum on and behind the throat plate with a special (not all THAT special) adaptor that I made up, having been caught out by a build up a few years ago.

 

With regard to the period that we were away, I'm thinking that there was probably already a build up of CO when the boat was visited by family but (at that time) it was below the alarm threshold. They wouldn't have looked at the monitor, there would be no reason to, or so we thought 🥺. Maybe there was still 'combustion' taking place in the ashes? I know ash can stay hot for a long time (48hrs in my experience) if there is any unburnt fuel (coal) within the ash and it produced plenty of CO.

 

As I said, I've tried a new alarm and the problem still exists. Two separate alarms were sounding on the fateful day but whilst the first reads from 10ppm the second only reads from 30ppm and is some distance from the stove (by my head in the bedroom!) so it rarely reads with our low level problem.

 

Thanks for the suggestions though 

 

[matty40s]

What you may also find with a change in wind direction is the flue doesnt draw well, especially if you have one of those Bird directional toppers that hasnt turned round with the wind.....the wind will be directed back down the flue.

We have had an East wind this week....but not a strong one, so it might not have shifted the bird round.

 

 

[Richardcn]

29 minutes ago, matty40s said:

What you may also find with a change in wind direction is the flue doesnt draw well, especially if you have one of those Bird directional toppers that hasnt turned round with the wind.....the wind will be directed back down the flue.

We have had an East wind this week....but not a strong one, so it might not have shifted the bird round.

 

 

I often wondered about that potential problem..  which is why we have only a bog standard hat. Good point though👍

[MtB]

23 hours ago, BEngo said:

Have  you checked that the inside of the stove is clean, particularly below the top flue inlet and behind the back boiler or on top of the baffle plate?

 

CO production soars if the fuel is damp.

 

If the stove was  OK CO wise 36 hours after filling, then something has changed after that.

 

  I would  expect the stove to be out and cold by then,  (mine struggles to go for  much over 24 hours) as it seems  you did.  A stove  that is out does not produce CO. I would be inclined to look again for  possible other sources of CO or gases that trigger CO alarms.  Is the alarm OK- does it pass the joss stick check?

 

N

 

 

Following on from this, I notice the ash in a full-ish ash pan will continue chucking out CO long after the stove itself has run out of fuel and gorn out. Once the coals stop burning, flue flow will stop too so any CO leaking from the (hot inside) ash pan might stop going up the flue and just generally ooze out of the stove into the saloon. 

 

I wonder if this peak in CO Richard has discovered after a stove has gone out is actually much more commonplace than lots of us realise.

 

 

[Richardcn]

38 minutes ago, MtB said:

 

Following on from this, I notice the ash in a full-ish ash pan will continue chucking out CO long after the stove itself has run out of fuel and gorn out. Once the coals stop burning, flue flow will stop too so any CO leaking from the (hot inside) ash pan might stop going up the flue and just generally ooze out of the stove into the saloon. 

 

I wonder if this peak in CO Richard has discovered after a stove has gone out is actually much more commonplace than lots of us realise.

 

 

You may well be on to something there. The only evidence that I have to counter that argument is that we never had the problem before, not in all our (meagre) years of boating. Our particular problem showed it's ugly face again today, regular as clockwork, even though the stove was still pretty warm and obviously burning (the flue was still hottish). The only difference to any other time of the day is that the fuel is old (last added about 8pm yesterday) and there is plenty of ash in the chamber (ie not riddled). We went out leaving 3 hoppers open (deliberately) and the level was about 16ppm on our return. Without the windows open I've no doubt we would have been up in the 30's or more! 🥺 Since I stoked it up again late pm the problem has, once again, disappeared. I'll probably reseal the bottom door tomorrow as I wasn't completely happy with my first attempt, a bit too much glue. I doubt it will solve the problem though as any extra air gap at the bottom just makes the fire draw more. It's another thing ticked off though, until I can check the rear plate (awaiting a mild(er) day). I may try taping up the panel joints with aluminium tape at some point, maybe one at a time, to see if that's the cause. I'll update as I go.

 

Thank you for your input.

Richard

[ditchcrawler]

2 minutes ago, Richardcn said:

  until I can check the rear plate (awaiting a mild(er) day).  

 

Thank you for your input.

Richard

I think I would be doing that sooner rather than later 

[MtB]

11 minutes ago, Richardcn said:

The only evidence that I have to counter that argument is that we never had the problem before, not in all our (meagre) years of boating.

 

I can't help but wonder for how many of those (meagre) years of boating you had a decent CO monitor displaying PPM! 

 

 

[Richardcn]

1 minute ago, ditchcrawler said:

I think I would be doing that sooner rather than later 

Yes, worry not, I am not going to delay unnecessarily. I have already had a good look (with the heat shield still fitted) and to be honest I don't think that's the problem. It doesn't look any different to when I inspected it last year and I did put a bead of Envirograf around the plate for good measure. Of course, things fail and so I'm open minded as yet but I can't see any obvious movement of the plate or any gap and I don't want to go thumping around with a fire burning and then also leave us with no heating and no spare plate to fit (maybe I'll order the parts just in case).

4 minutes ago, MtB said:

 

I can't help but wonder for how many of those (meagre) years of boating you had a decent CO monitor displaying PPM! 

 

 

I was trying to remember that info as I was typing my previous reply. Pretty sure we have had a decent monitor there from very early on. Very probably after getting good advice from herein! (My god I did read A LOT on here back then 🧐). We didn't, however, have the 3 monitors that we now have with the one in the back cabin letting me know when the batteries are being thoroughly charged 😆

[ditchcrawler]

48 minutes ago, Richardcn said:

Yes, worry not, I am not going to delay unnecessarily. I have already had a good look (with the heat shield still fitted) and to be honest I don't think that's the problem. It doesn't look any different to when I inspected it last year and I did put a bead of Envirograf around the plate for good measure. Of course, things fail and so I'm open minded as yet but I can't see any obvious movement of the plate or any gap and I don't want to go thumping around with a fire burning and then also leave us with no heating and no spare plate to fit (maybe I'll order the parts just in case).

 

Can you not see behind the stove with a mirror ?

[David Mack]

2 hours ago, MtB said:

 

I wonder if this peak in CO Richard has discovered after a stove has gone out is actually much more commonplace than lots of us realise.

Yes. I've read of a few instances of high CO levels, including fatalities, resulting from fire/stove ash or barbecues (with glowing embers beneath the surface) left to cool slowly in or close to living/sleeping spaces.

And never put your stove ash in a bucket in the front well deck, unless it is cold. Otherwise CO from smouldering embers could find its way into the cabin through low level vents in the front doors/bulkhead.

[Arthur Marshall]

If there's no proper pull from the flue, fumes could easily leak through the top vent (it does in my fire at home). I suspect the throat plate is impeding the up draught when the fire is low - might be worth taking it out for a few days and see if the problem persists. 

[bizzard]

If this throat plate is the half moon shaped thing held in by two nuts it needs to be removed, they're only for use in houses with much longer chimney's which give a stronger draw on the fire. Left in it will clog up the flue pipe.

[Tracy D'arth]

Is there sufficient ventilation into the boat?  If the cabin is sealed up tight there may be an inversion in the flue when it starts to cool off. 

[MtB]

20 minutes ago, Tracy D'arth said:

Is there sufficient ventilation into the boat?  If the cabin is sealed up tight there may be an inversion in the flue when it starts to cool off. 

 

 

Or there might even just be a pile of rust flakes and soot on top of the baffle plate mostly blocking the flueway. I certainly used to get this periodically with my Squirrel before I discovered it worked just as well with the baffle plate completely removed. 

 

Once the fire goes out and the flue cools a bit, the draught through the restricted gap will reduce to near nothing.

 

 

[matty40s]

1 hour ago, MtB said:

 

 

Or there might even just be a pile of rust flakes and soot on top of the baffle plate mostly blocking the flueway. I certainly used to get this periodically with my Squirrel before I discovered it worked just as well with the baffle plate completely removed. 

 

Once the fire goes out and the flue cools a bit, the draught through the restricted gap will reduce to near nothing.

 

 

I used my Squirrel for about 10 years before I even realised that most people used baffle plates...

On long journeys in Winter, I could chuck twigs down the chimbley to keep the fire going during the day without having to go inside the boat!

[Arthur Marshall]

I've always chucked the baffle plate out. It's fine in my fire at home wuth a proper chimbley but a design flaw in a boat stove.

[blackrose]

I just slide the baffle plate forward in my stove so there's a 1" gap at the back. There's no need to get rid of it completely, at least not on my stove. Having that gap at the back improves the draw but the plate still functions to some degree. Half the draw goes around the front of the plate and half around the back so there's still some "diversion". Without any baffle plate at all much more of the heat will go straight up the flue and out the chimney.

 

17 hours ago, Tracy D'arth said:

Is there sufficient ventilation into the boat?  If the cabin is sealed up tight there may be an inversion in the flue when it starts to cool off. 

 

Is any canal boat cabin really sealed up tight? I know the bss rules on ventilation are now advisory rather than mandatory, but all the canal boats I've ever seen still have fixed non-closeable ventilation and only an idiot would block all their vents while running a stove. The OP certainly doesn't sound like the type.

Edited March 10 by blackrose