Back boiler

[snaps]

Greetings friends,

 

I have a plan which I think will work, but need a little advice. I have a morso squirrel stove to which I am going to fit a back boiler. I then plan a gravity fed single Rad (which will be at head height to assist in the thermal flow). What sort of diameter pipes should I have for flow and Return?

 

This closed system is a bit of a time bomb so how best to relieve the pressure?. I was thinking of a bottle valve on the radiator's highest point, and maybe a small crome type? expansion vessel as well, if there are such devices for the Rad which is on view in the bathroom. Or is a bigger surecal type one better hidden away but not at the highest point?

 

Currently the bottle valve (an automatic air bleed) on the rad and an expansion vessel hidden away seems the way forward in my mind anyhow???

 

Regards

 

Si

[down the north]

Hiya,

havent done anything on a morso, but i've a bb on an epping size range, made it out of 4mm plate, brazed some 22mm pipes on the back and it runs to a stainless calorifier and also in paralell a couple of 22 mm pipes to a long loop in the forcabin, works a treat with convection circulation and about 10 ft away on a gradual rise. Wouldnt bother with a closed system, fit a small header tank somewhere, but your problem might be loosing all the heat, which will depend on the size of the bb, you dont want it boiling up in no time, but try not to cover up a 'too big' bb with fire bricks, you'll get condensation between and it will corrode quickly,

hope this helps,

martin, bbon my epping @ 6" x 6" x 2" roughly..

[snaps]

Hiya,

havent done anything on a morso, but i've a bb on an epping size range, made it out of 4mm plate, brazed some 22mm pipes on the back and it runs to a stainless calorifier and also in paralell a couple of 22 mm pipes to a long loop in the forcabin, works a treat with convection circulation and about 10 ft away on a gradual rise. Wouldnt bother with a closed system, fit a small header tank somewhere, but your problem might be loosing all the heat, which will depend on the size of the bb, you dont want it boiling up in no time, but try not to cover up a 'too big' bb with fire bricks, you'll get condensation between and it will corrode quickly,

hope this helps,

martin, bbon my epping @ 6" x 6" x 2" roughly..

 

Thanks Martin,

 

Yeah I had not considered an open system, does the header tank have a lid? Where did you get it from? are there any decorative/well engineered eg stainless ones about.?

 

I guess I could go the whole hog with bubble valve pressure release vessel and pressure release valve on a closed system.

,

I plan to run to a port hole high Radiator so a good rise on the hot side and them come down back through the calorifier second coil for a bit of extra heating of the water tank.

 

If the water tank is hotter than the returning water I am having a non return valve to stop the tank bleeding hot water to the Rad?

 

I plan to use 22mm brass/crome pipe on exposed run's? Or similar? any idead here also?

 

Si

[Chertsey]

We shall follow this with interest. We had a back boiler on the 'custom built' back cabin stove, but decommissioned it because it was always boiling up; it had an expansion tank in the engine room via which it would distrubute water and steam all over everything and generally be quite terrifying.

However we want to reinstate it as it both heated water in the calorifier and the bathroom radiator and was ferociously efficient.

The idea now is to have an expansion tank (so stop air being drawn into the system?) but for this to be fully enclosed and vented through the roof. It could also be topped up that way. Does that sound sensible?

We were planning to reduce the size of the firebox with firebricks but are you suggesting Martin that this isn't a good idea? Perhaps if we paid more attention to what fuel we were using this would help prevent it getting too hot. It was always a bit inconvenient having to sit watching it with a bucket of water to hand anyway....

No doubt PB & MP will be along in a moment to tell me I've got it all wrong, but I'm just trying to get it straight in my head. They are going to go and Look At It next week.

Finally, having used the stove in the meantime without water in the the bb, are we likely to have done irreparable damage to it?

[snaps]

We shall follow this with interest. We had a back boiler on the 'custom built' back cabin stove, but decommissioned it because it was always boiling up; it had an expansion tank in the engine room via which it would distrubute water and steam all over everything and generally be quite terrifying.

However we want to reinstate it as it both heated water in the calorifier and the bathroom radiator and was ferociously efficient.

The idea now is to have an expansion tank (so stop air being drawn into the system?) but for this to be fully enclosed and vented through the roof. It could also be topped up that way. Does that sound sensible?

We were planning to reduce the size of the firebox with firebricks but are you suggesting Martin that this isn't a good idea? Perhaps if we paid more attention to what fuel we were using this would help prevent it getting too hot. It was always a bit inconvenient having to sit watching it with a bucket of water to hand anyway....

No doubt PB & MP will be along in a moment to tell me I've got it all wrong, but I'm just trying to get it straight in my head. They are going to go and Look At It next week.

Finally, having used the stove in the meantime without water in the the bb, are we likely to have done irreparable damage to it?

 

Hello

 

No water in the back boiler is not advisable, depending on the material for the BB it can cause heat damage/warping etc and even melt down it in extreme situations. It is due to the fact that the metal is so much thinner on the BB than the stove itself so it will not last as long without the cooling effect of the water.

 

An expansion tank of a suitible size at the highest point on the system is going to be a good solution, but in addition it appears your system was boiling off, this is probably due to lack of flow if it is a gravity fed system (ie no pump). If this is the case you need to tame the fire somehow by reducing the amount of heat the BB is exposed to. This can be done using fire bricks inside the fire of a ceramic plate at the back.

 

Regards

 

Si