Franco Belge model 3707 - water under ash tray. Any ideas please?

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LKR

New Member
Aug 9, 2025
5
Tasmania, Australia
Hello dear people 😊

Would be grateful for any thoughts or experiences.

We bought a house last year that has a Franco Belge fuel stove (model 3707 circa 1985) that operates a hydronic heating system that heats the house through European style panel radiators. We burn native hardwoods as fuel. The boiler is water not oil.

I didn’t light the fire last night and this morning could smell a creosote type smell near the stove. Decided to empty ash tray before relighting this morning and found beneath the tray to be a wet, sticky, black, mess. Have emptied tray many times before, and there’s never been anything except dry ash beneath.

It’s weekend in Australia, and have sent out some emails, and now found this forum online! Would be most grateful for any thoughts or insights into what’s going on. I have extremely limited experience with fuel stoves, and won’t re light it until I know it’s ok to do so.

Thank you in advance for time in considering my question 🙏🌻

[Hearth.com] Franco Belge model 3707 - water under ash tray.  Any ideas please?
 
Condensation. Do you have hot humid weather, then cold at night? I guess it's your "winter" there now?
 
Have there been any big storms with heavy wind-driven rain? If so, this might just be a one off.
Check the chimney cap to verify that it has not blown off or corroded through. Check the chimney flashing storm collar too. It may need fresh caulking with silicone caulk. Take some pictures of the chimney flashing and cap while up on the roof and post them.
 
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Thanks very much for your replies Whitenuckler and begreen 🙏

It seems to be too much for condensation (I think 🤔) We have had morning frosts followed by unseasonally warm days for here. Have plants coming up in the past weeks that didn’t appear until mid September last year. No heavy rain showers in the past weeks.

The flue runs through a chimney stack and the cap is intact. We have the chimneys/flues checked and cleaned every April. However, we have suffered structural damage due to use of a heavy vibration roller on an an adjoining housing development site. Structural engineer currently compiling his report. There are visible fine cracks in the chimney structure - but wouldn’t have guessed this could be effecting the fuel stove and flue if they are a unit within the housing of the chimney? 🤔

I guess my greatest concern is if it is water leak in the fuel stove/water coils system.

Apologies if I’m using the wrong words/terms here 🙈
 
Thanks very much for your replies Whitenuckler and begreen 🙏

It seems to be too much for condensation (I think 🤔) We have had morning frosts followed by unseasonally warm days for here. Have plants coming up in the past weeks that didn’t appear until mid September last year. No heavy rain showers in the past weeks.

The flue runs through a chimney stack and the cap is intact. We have the chimneys/flues checked and cleaned every April. However, we have suffered structural damage due to use of a heavy vibration roller on an an adjoining housing development site. Structural engineer currently compiling his report. There are visible fine cracks in the chimney structure - but wouldn’t have guessed this could be effecting the fuel stove and flue if they are a unit within the housing of the chimney? 🤔

I guess my greatest concern is if it is water leak in the fuel stove/water coils system.

Apologies if I’m using the wrong words/terms here 🙈
I am not familiar with your stove and system, however there may be a way to pressure test the piping with compressed air.
I am also not sure what covers can be removed for a visual inspection. If it was installed in 1985, that would make it 40 years old, and there could be corrosion and pin holes forming.
 
I am not familiar with your stove and system, however there may be a way to pressure test the piping with compressed air.
I am also not sure what covers can be removed for a visual inspection. If it was installed in 1985, that would make it 40 years old, and there could be corrosion and pin holes forming.
Thanks Whitenuckler,

Yes, have this concern regarding the age of the unit. It’s an uncommon system for Australia. The original installer had a technician that would come from another state to service it annually - but he’s 95 now!! Hoping to get a reply to emails on our Monday morning. A little nervous what the outcome will be. I’ve been told there’s no units in Australia capable of managing so many panel radiators over such a big floor space 🙈

Will follow up this post with outcomes when I know more.

Many thanks for thoughts and time in replying, it’s much appreciated 🙏🌻
 
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Based on this there may be a flaw in the flue system. Describe the flue system from stove top to chimney cap, in detail. Does it transition from the stainless steel stove pipe to clay liner in the chimney?
 
Thank you for your message begreen.

The flue extends the full length of the chimney. There is a “bend” in the flue that is not visible. I’m attaching a couple of photos taken of area directly above the fuel stove as the flue extends into the chimney. An extraction fan and light are fitted there. The bend in the flue is not far above the board the extraction fan and light are mounted on.
 

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Dear all,

Cogs slowly turning in brain! Have also been using a spray on creosote remover on the inside of the fire box since 28 July. The information on the product mentioned it would cause the creosote to become white ash. Directions indicated 60 squirts to be applied every couple of days initially. I’ve used about 40 squirts every 3 days.

There’s no creosote sludge IN the ash tray/pan, it’s all underneath.

Could this spray be the cause of the sludge? Has anyone had this happen before?🤔
 
Dear all,

Cogs slowly turning in brain! Have also been using a spray on creosote remover on the inside of the fire box since 28 July. The information on the product mentioned it would cause the creosote to become white ash. Directions indicated 60 squirts to be applied every couple of days initially. I’ve used about 40 squirts every 3 days.

There’s no creosote sludge IN the ash tray/pan, it’s all underneath.

Could this spray be the cause of the sludge? Has anyone had this happen before?🤔
That could very well be the cause of the wet area. If the solvent is has a certain smell after sprayed on, you might collect some drippings
and try to smell them in another room or outside. Also if the solvent is flammable (you can test outside) then if your drippings are flammable that would match. If you are done your treatments, perhaps the problem will go away.