Hot water by back boiler

[gary955]

i was almost looking forward to the colder weather so that my solid fuel stove would provide a constant supply of hot water.

Lit my squirrel for the first time the other night and the top pipe of the convection curcuit got hot all the way down to the boatmans cabin where the hot water tank is....but no hot water! The return pipe stayed stony cold. After two and a half hours I gave up and started the engine.

when the stove was not roaring the hot pipe receded back to the engine room. What am I doing wrong?

[bottle]

Air lock ?

 

Pipes too small ?

 

Pipe run incorrect ?

 

You may need to fit a pump.

[gary955]

Air lock ?

 

Pipes too small ?

 

Pipe run incorrect ?

 

You may need to fit a pump.

Pipes are 22mm I think. The header tank is half full and the bleed nipple at the stove has no air in it. The top pipe run is at the top of the hull with the bottom at skirting board level. there are two radiators in the circuit and I had both turned off.

[Dovetail]

i was almost looking forward to the colder weather so that my solid fuel stove would provide a constant supply of hot water.

Lit my squirrel for the first time the other night and the top pipe of the convection curcuit got hot all the way down to the boatmans cabin where the hot water tank is....but no hot water! The return pipe stayed stony cold. After two and a half hours I gave up and started the engine.

when the stove was not roaring the hot pipe receded back to the engine room. What am I doing wrong?

 

I think the system must have been circulating otherwise the water would have boiled in the pipe.

 

I think it is going to take a lot longer to heat the water than you think and once you have your fire going for many an hour and perhaps hotter than your first test.

 

Good look

Edited September 24, 2010 by Dovetail

[jelunga]

unless thr radiators do not have a bypass pipe. So when they are turned off NO water flows at all? That is the way an idiot fitted the heating system in our boat. So if I turn one off, they are all off and no water flows.

But it could be something else. If this was the case for you, I would expect the water to boil in the boiler!!

[gary955]

unless thr radiators do not have a bypass pipe. So when they are turned off NO water flows at all? That is the way an idiot fitted the heating system in our boat. So if I turn one off, they are all off and no water flows.

But it could be something else. If this was the case for you, I would expect the water to boil in the boiler!!

Yes both rads are tee'd off between the feed and return pipes so are effectivly in parralel, not series. turning them off does not restrict flow to the hot water tank. Maybe I do need to have the stove hotter for longer.

The boat is called Pheadrus and the previous owner posted here so if you read this perhaps you could let me know if the system works well without a pump.

[bottle]

Pipes are 22mm I think. The header tank is half full and the bleed nipple at the stove has no air in it. The top pipe run is at the top of the hull with the bottom at skirting board level. there are two radiators in the circuit and I had both turned off.

 

There should be a 'bleed valve' at the highest point of the system, I know you had the rads turned off but they may want bleeding as well.

[gary955]

There should be a 'bleed valve' at the highest point of the system, I know you had the rads turned off but they may want bleeding as well.

Yes there is an automatic bleed about a foot higher than the top pipe and I bled manually just to make sure

[twooh10]

How long is your boat/pipes? My 70 footer has a non-professional installed system which is far too long with too many radiators, so without the stove raging like a furness it never gets warm in the back cabin & there's no hope of getting hot water off it, so the tank is on permanent bypass!

[Gibbo]

Pipes are 22mm I think. The header tank is half full and the bleed nipple at the stove has no air in it. The top pipe run is at the top of the hull with the bottom at skirting board level. there are two radiators in the circuit and I had both turned off.

 

Unless you have a back to front boat that would imply the pipes go downhil from the fire to the calorifier and also that the bleed valve isn't at the highest point. That kinda won't work.

[Smelly]

22mm is a bit thin... 28 would be better.

 

We've got 1kw of rads running slightly down the boat, to stern; they work quite well. It takes about 3 days from cold to get the water warm though, although the other 750w of ears heading "uphill" probably don't help.

 

Assuming your cal' is uphill, do you know how much pipe is in the water? It's been said that some Cal's don't have a big enough coil to make for an effective cooling circuit inside the tank

 

 

Grr, phone, read ears as rads...

 

Have you tried searching phaedrus's old posts?

[routrax]

I thought the pipes had to go up by about 4deg?

 

Smelly, it takes 3 days to get the other end of your boat warm?

 

I'm about to order the bits to fit my squirrel with boiler next weekend and am wondering if I should bother and just fit another stove at the other end!

[Dovetail]

Yes routrax the pipes should go up from the boiler and ideally slightly down to the boiler on return.

 

you also have to balance the rads ect with your back boiler so to few rads ect you run the risk of boiling the water in the pips to many rads ect the rad at the end of the run stays cold

[real_vibes]

My back boiler and rads work great (squirrel with BB running 3 rads via pump). The only problem is the noisy pump.

 

Are there any tried and tested solutions for muting te pump? Anninsulated box around the pump? A brand which is quiet? I would love to have it just that bit quieter as it is going to be on a lot this winter!