gary955

Thanks for the reply but I think you misunderstood, or maybe I didn't explain very well. Its the water in the calorifier thats getting to 36 degrees. The water from the boiler is very hot, much too hot to touch the pipework. I wonder if during its journey to the calorifier down 34 feet of unlagged copper pipe, its radiating most of its heat to the surrounding air, and if that pipe was lagged, more of the hot water would transfer its energy to the calorifier. Now that the thermosyphon is working I'd rather avoid a pump, if I can get hot water without one. I guess even at 36 degrees it would very much reduce the amount of time I have to run the engine or immersion heater.

I didn't really expect my calorifier to work on a thermosyphon. It never has in the past and I was resigned to fitting a pump. You see it's not very well designed according to accepted wisdom. It has 22mm pipes rather than 28mm, it has ordinary radiator valves instead of full bore gate valves, and the top pipe run down the boat is under the gunnel, which because of the trim of the boat, means it runs slightly down hill from the boiler. Recently while fitting a new stove flue I cleaned the (very coked up)boiler heat exchanger and re-sited the back boiler bleed valve to ensure that all the air would be expelled, and blow me!! the system has stopped gurgling and started working! all the way to the calorifier. I'm not getting piping hot water, the tank temp rises to a max of about 36 degrees, and the return pipe to the boiler is at no more than ambient temp, so the system seems to be using all the energy available. How can I improve efficiency to the calorifier? Would lagging the top pipe increase the temp of the hot water to the rear of the boat where the calorifier is, without resorting to a pumped system? What do you think?

Cheers Nice to have my mind put at rest by someones actual experience with exactly the same boiler. What temp does your pipe stat trip at? Ahh Just noticed that you have answered that on another thread

No I meant the heat exchanger in the boiler. The copper coil in the calorifier would be fairly tolerant of sudden temp change but temp rise by the time the hot water reaches it will be relatively gentle anyway. The heat exchanger in the boiler, when lit from cold, will get very hot by the time water thermosyphons up to the pipe stat. Then the pump will trip in, suddenly pushing all the hot water out, to be replaced with very cold water from the the bottom run of the heating system. Once the whole system has warmed up the temp difference will be less dramatic its just the first hour or so from cold that worrries me. Hopefully people running this system can tell me that I'm worrying uneccisarily

Ah...Good idea....maybe even higher 55-60 degrees? The calorifier is well insulated, so wont need to be heated overnight, or when I'm at work, and the stove is just idling One thing that worries me a little with a thermostat controlled pump, is the possible effect of thermal shock to the heat exchanger as all the hot water is suddenly replaced with cold. On another note. Should I paint my mild steel flue or just "stove black" it with paste? I bought some stove paint spray but the instructions state that it must be cured by firing the stove, within 8 hours of painting it, and thats not going to be easy to fit round my work pattern. I really need to paint it one day and fit it the next.

I guessed that transmitted vibration would be the source of most noise. My calorifier is under the side bench in the boatmans cabin so I thought of gluing a softish rubber block onto the base plate benieth the calorifier to mount the pump on and coupling the water pipe with rubber hose as well. Airborn noise would be insulated by the calorifier and the padded seat box, and transmitted vibration would be insulated by the rubber block and heavy steel plate which in turn will be damped by the water benieth it.....................thats not how you spell benieth is it?

Well 30db is very quiet. Interestingly none of the expensive boat central heating pumps spec sheets seem to give noise level, but in other respects seem similar in performance to the quoted spec of the cheapy chinese jobbie, including power consumption. Although in the pictures they do look very much better quality.

Why avoid cheap pumps? The little ebay pumps for £10 will pump 300lph, seem pretty quiet at 30db and draw just over 1amp. Seems like a good way to experiment, at minimal cost, whether my back boiler will heat the calorifier. I could have it swiched by a thermostat on the back boiler outlet pipe, maybe just before the first radiator. If the pump fails, the two radiators will thermosyphon as before to prevent the water boiling.

I think the rear flue plate could be modified to bolt up from the outside. The fixing appears to be a couple of lugs that fit over two studs on the inside of the plate. These studs could be removed and the holes drilled all the way through the plate to give clerance for similar sized bolts. Now put the lugs over two new bolts and weld them on at the bolt head. Cut a slot across the end of the bolts at the opposite end, in line with the lugs so that you will know which way they are pointing. Now the bolts can be passed through the plate on the inside and the lugs turned sideways to allow the plate to be offered up to the stove. When in place turn the lugs through 90 degrees and tighten them up with nuts on the outside sealed with copper washers. Job done! Alternatively, I have found that i can just get my hand over the baffle plate from the the front of the stove so I'll see how easy it is to clean up from there, next spring.

Yes but thats not possible when the baffle plate is also the boler heat exchanger, unfortunatly. You must type faster than me!!

I now have my new flue pipe cut to length and will paint it tommorrow before fitting. Today I decided I'd clean the stove up. Noticing a build up of carbon behind the baffle plate I set to work with a chisel. Several hours later I was suprised to find that the horizontal top surface of the baffle was in fact a four inch thick accumalation of carbon, and the rear of the baffle plate was actually at 45 degrees. Even more surprising was the discovery that the baffle plate was also the heat exchanger for the boiler! The carbon was never thick enough to restrict the flue so the stove was safe but 50% of the boiler was effectively insulated. Now that its clear i expect it will be much more efficient so I may add a pump into the curcuit to pull the hot water through the calorifier (it never worked on the thermosyphon) i expect I'll try one of those cheapy ebay jobbies. But I have a problem! how do I stop a similar build up of soot turning to solid carbon in the future? There is rear flue plate (Morso squirrel for those who hadn't guessed)which would give access to the back of the baffle, but I'm pretty sure that its bolted on from the inside. must I remove the flue every couple of years to keep the stove clean?

How would a non setting putty affect the security of the flue? Might it allow lateral movement that would over time threaten the integrity of the seal? My flue rises at a slight angle so is not entirely concentric in the top or bottom collars. It was very secure though and i'd like the new one to be equally as solid. Does the putty hold it firm?

Well it's out! Bit of a bugger of a job and very messy but its out. It was pretty badly corroded at the top. There seems to be a lot of cement left in the roof collar, perhaps a 3mm to 6mm ring all the way round for about 2.5" to 3" and its incredably difficult to dislodge. As it seems so sound, do the panel think it's OK to leave it in place, assuming the new flue would fit inside it?

Oh dear. I can well understand your frustration and would feel aggreived myself in your situation, but complaining about an overstayers on a moorings that you intend to overstay yourself is pretty thin ice!

There's also a drydock at Bradford wharf and I think two at Semington and possibly one at foxhangers. All below the Caen flight.

Maybe a little too close to the 13A limit? or even slightly over at 230v

The OP gives her location as Bath, so Newbury might be a bit of a stetch! 2 days for the blacking plus two or three weeks for the return journey!

Sallyboats at bradford on Avon did mine last year for £550 (55 ft) and I think the Somerset Coal Canal co are offering blacking at £10 a foot.

A pre winter sweep of my flue has revealed two small holes (one a pin hole) in the flue pipe near the ceiling. I'd assumed that I would have to remove the roof collar in order to get the flue out of it's spigot but a recent thread on stoves seems to suggest that the pipe could be wiggled up through the collar enough to clear the stove. Is this the case with all roof collars?

Wiring for a 1kw (or even 2kw) immersion heater can be as simple as putting a 13a plug on the end of the lead Assuming your boat already has 13a sockets of course.

Starcoaster. i have a little app on my Toshiba laptop that indicates power consumption. It's usually about 12-15w when connected to the internet through a dongle, which I think is less than 1.25a. My 80w solar panel can usually keep up with that but on really dull days (or at night) my 330ah bank doesn't seem to be bothered at all by the lappy, which runs from a 12v to 19v converter. Hope you have a gas fridge though!

Errr.....actually that was a joke! in response to suprise that an 18mm floor would compromise headroom.

Not over tall.......but I do like crystal chandelliers

Yes I agree, laminate never looks really convincing in comparison. Trouble is I'm laying this as a floating floor on top of the existing floor and the 18mm thickness of a good quality real wood floor would reduce the headroom of my boat enough for me to bump my head on light fittings! also I wold have to remove all the doors to trim the bottom off for clearance. 7mm laminate will fit under the doors and not rob me of too much headroom.

Planks aligned across the boat or down the boat. which would look best? Also I was thinking that, as a narrowboat is such a small space, I could reduce the expansion gap around the edge, for neatness.