heating

[colin loach]

Hi all. I want to fit a morse squrrial to my 50ft boat which is 35ft inside the heater will be situated about 6ft from the front. The bedroom is at the back then the bathroom is next, the boat is open plan apart from the bathroom do you think I will need radiators or maybe a echo fan will do, what do you all think. Colin.

[chris w]

A squirrel on its own (with an Eco fan) will heat the saloon perfectly and get the bedroom up to a comfortable background temperature. You will need rads though to heat the bathroom (towel rail) and provide additional heat in the bedroom. You want the towel rail anyway to dry towels!!

 

It's also good to have a second heating source like a diesel heater which can be timed to come on in the mornings. Very necessary in cold weather.

 

Chris

[colin loach]

A squirrel on its own (with an Eco fan) will heat the saloon perfectly and get the bedroom up to a comfortable background temperature. You will need rads though to heat the bathroom (towel rail) and provide additional heat in the bedroom. You want the towel rail anyway to dry towels!!

 

It's also good to have a second heating source like a diesel heater which can be timed to come on in the mornings. Very necessary in cold weather.

 

Chris

I didn’t really want to by another heater, but what do you think about running a rad in the bedroom via gravity and one in the bathroom by pump working off a timer. I have got no mains hook up where I am so I need to save my batteries as much as I can.

[chris w]

I have no experience of gravity systems but ask Blackrose (Mike) as he has such a set up.

 

Chris

[colin loach]

I have no experience of gravity systems but ask Blackrose (Mike) as he has such a set up.

 

Chris

Cheers Chris.

[blackrose]

Hi Colin,

 

First remember that radiators from a solid fuel stove don't provide additional heat they just help to distribute it a bit better. However, despite having rads myself I've actually found that most of the heat in my bedroom is (eventually) carried there by convection, not by the rad. I discovered this by doing a simple experiment: I closed the bedroom door! To be fair the rad's probably a bit small for the size of the bedroom.

 

Unfortunately this isn't one of those things where you can add rads on on later if it doesn't work without them - I think you've either got to buy a stove with a backboiler or without, so it involves a bit of thinking about first. You say the stove will be situated 6' from the front of the boat - is there any way it could go more centrally in the boat? It would save a lot of work on plumbing, but just remember that you have to construct a fire resistant hearth under and around your stove.

 

Also how long is your bedroom and how wide is the corridor past the bathroom and the doorway into the bedroom. I'm just trying to work out if you could get away without rads? It would mean leaving bedroom & bathroom doors open (most of the time!) to make sure the heat got in there. Depending on the length of your bedroom it sounds like the distance between your stove & bedroom door is about 20'.

 

My backboiler central heating system is run on thermocycling (convection & gravity) without a pump. It works really well and both rads get very hot but it's only about 15' (one way) to the last rad in the bedroom. It's obviously simpler in operation than using a pump and much more satisfying, but where many thermocycling systems fail is where the last rad is perhaps 40' + away from the stove fed by pipe that's too thin and it doesn't get very hot. You could certainly get the bedroom rad hot without a pump on a 20'-25' main pipe run as long as the pipe you use is as wide bore as the outlets from your backboiler allow. I think the Squirrel's outlets are 22mm? The other benefit of a rad in the bedroom would be that you could have a rad in the bathroom too (assuming the bathroom is on the same side of the boat as your main pipe run?) In your case I only think you need two small rads - one in the bathroom and one in the bedroom. If you don't want a pumped system all pipework should be in copper because it will be on display and is part of the heat radiation system.

 

Thermocycling is a bit of a black art - you're basically trying to move hot water around the system without a pump, so try to make it easy for the water to move. You need to try to configure the system so that the hot water can rise as it leaves the backboiler and over the top of the first rad. Use 15mm pipe to T off the main run and connect to the first connection at the top of the rad (not the bottom - you can only do that with a pumped system and for this reason I don't think you can have a towel rail type radiator). Then the main run should then continue horizontally or slightly falling to the top of the second rad. Take the main run right around the final rad and T off to all 4 connections to better facilitate circulation. The main run then returns under the rads T-ing off to the diagonally opposite connection of the bathroom rad that you connected at the top. If possible try not to make the main run rise to get back into the backboiler because as the water loses heat it wants to fall. That's difficult on a long run. The other thing that I did was at 90 degree bends on the main run I used 2 x 135 degree joints instead to allow the water to flow more easily.

 

So you can see that with a thermocycling system you will be restricted on the physical height of the radiators due to the fact that the pipework should go right around them and the pipework should be horizontal or falling from the first rad. Given that you'll probably want the main run under the gunwhale you can see the problem. I used double wall rads (or whatever they're called), to overcome this height restriction. You should also try to approximately match the btu (or Kw) heat output of the rads (+ a bit for the pipework) to that of your backboiler.

 

Almost forgot - you'll need a header tank coming off the main run positioned higher than the rest of the system. If it comes off the top run at the highest point of the system it will be self-bleeding, but then you may find it means extra humidity in the boat. If the header tank isn't at the very top of the main run you'll need a bleed valve at the top. I used an old Mercedes radiator reservior and connected it up with car heater hose. I vented the top of the header tank outside the boat with a bit more hose and a skin fitting to get rid of any humidity. Fit a small keyed draining tap to the very bottom of the main run before it goes back into the backboiler. Fill the system to the bottom of the header tank with a 50/50 mix of antifreeze & water or just water and inhibitor at the correct proportions.

 

If you can't be bothered with all this just connect the rads as you wish and chuck a pump in the system! Actually even if you go for thermocycling you could fit 2 gate valves into the bottom of main run about 18" apart so you can easily fit a pump if the thermocycling system doesnt work very well. (No faith in my own advice that's my problem!) It's not a bad idea to fit those gate valves even if you go for a pumped system in the first place so that when the pump breaks it can be easily replaced. Just make sure that nobody closes the valves before or during stove use.

 

As you can see, on a boat the length of yours it would be much easier to have a more centrally located stove without a backboiler.

 

Hope this helps - Mike

Edited March 1, 2008 by blackrose

[Boaty Jo]

I'll back up Blackrose's obvious knowledge here with an endorsement - our friends have a Squirrel situated about 6 feet from the front of their 60 footer. 2 (or 3) rads fed by thermocycling and their boat is lovely and warm. Do try and get a rad in the bathroom though if possible.

It is also relevant if you are on the boat enough to keep the fire ticking over 24/7. This could be where an additional Aldi or diesel system may prove useful.

[colin loach]

Hi Colin,

 

First remember that radiators from a solid fuel stove don't provide additional heat they just help to distribute it a bit better. However, despite having rads myself I've actually found that most of the heat in my bedroom is (eventually) carried there by convection, not by the rad. I discovered this by doing a simple experiment: I closed the bedroom door! To be fair the rad's probably a bit small for the size of the bedroom.

 

Unfortunately this isn't one of those things where you can add rads on on later if it doesn't work without them - I think you've either got to buy a stove with a backboiler or without, so it involves a bit of thinking about first. You say the stove will be situated 6' from the front of the boat - is there any way it could go more centrally in the boat? It would save a lot of work on plumbing, but just remember that you have to construct a fire resistant hearth under and around your stove.

 

Also how long is your bedroom and how wide is the corridor past the bathroom and the doorway into the bedroom. I'm just trying to work out if you could get away without rads? It would mean leaving bedroom & bathroom doors open (most of the time!) to make sure the heat got in there. Depending on the length of your bedroom it sounds like the distance between your stove & bedroom door is about 20'.

 

My backboiler central heating system is run on thermocycling (convection & gravity) without a pump. It works really well and both rads get very hot but it's only about 15' (one way) to the last rad in the bedroom. It's obviously simpler in operation than using a pump and much more satisfying, but where many thermocycling systems fail is where the last rad is perhaps 40' + away from the stove fed by pipe that's too thin and it doesn't get very hot. You could certainly get the bedroom rad hot without a pump on a 20'-25' main pipe run as long as the pipe you use is as wide bore as the outlets from your backboiler allow. I think the Squirrel's outlets are 22mm? The other benefit of a rad in the bedroom would be that you could have a rad in the bathroom too (assuming the bathroom is on the same side of the boat as your main pipe run?) In your case I only think you need two small rads - one in the bathroom and one in the bedroom. If you don't want a pumped system all pipework should be in copper because it will be on display and is part of the heat radiation system.

 

Thermocycling is a bit of a black art - you're basically trying to move hot water around the system without a pump, so try to make it easy for the water to move. You need to try to configure the system so that the hot water can rise as it leaves the backboiler and over the top of the first rad. Use 15mm pipe to T off the main run and connect to the first connection at the top of the rad (not the bottom - you can only do that with a pumped system and for this reason I don't think you can have a towel rail type radiator). Then the main run should then continue horizontally or slightly falling to the top of the second rad. Take the main run right around the final rad and T off to all 4 connections to better facilitate circulation. The main run then returns under the rads T-ing off to the diagonally opposite connection of the bathroom rad that you connected at the top. If possible try not to make the main run rise to get back into the backboiler because as the water loses heat it wants to fall. That's difficult on a long run. The other thing that I did was at 90 degree bends on the main run I used 2 x 135 degree joints instead to allow the water to flow more easily.

 

So you can see that with a thermocycling system you will be restricted on the physical height of the radiators due to the fact that the pipework should go right around them and the pipework should be horizontal or falling from the first rad. Given that you'll probably want the main run under the gunwhale you can see the problem. I used double wall rads (or whatever they're called), to overcome this height restriction. You should also try to approximately match the btu (or Kw) heat output of the rads (+ a bit for the pipework) to that of your backboiler.

 

Almost forgot - you'll need a header tank coming off the main run positioned higher than the rest of the system. If it comes off the top run at the highest point of the system it will be self-bleeding, but then you may find it means extra humidity in the boat. If the header tank isn't at the very top of the main run you'll need a bleed valve at the top. I used an old Mercedes radiator reservior and connected it up with car heater hose. I vented the top of the header tank outside the boat with a bit more hose and a skin fitting to get rid of any humidity. Fit a small keyed draining tap to the very bottom of the main run before it goes back into the backboiler. Fill the system to the bottom of the header tank with a 50/50 mix of antifreeze & water or just water and inhibitor at the correct proportions.

 

If you can't be bothered with all this just connect the rads as you wish and chuck a pump in the system! Actually even if you go for thermocycling you could fit 2 gate valves into the bottom of main run about 18" apart so you can easily fit a pump if the thermocycling system doesnt work very well. (No faith in my own advice that's my problem!) It's not a bad idea to fit those gate valves even if you go for a pumped system in the first place so that when the pump breaks it can be easily replaced. Just make sure that nobody closes the valves before or during stove use.

 

As you can see, on a boat the length of yours it would be much easier to have a more centrally located stove without a backboiler.

 

Hope this helps - Mike

That as been a great help, thanks very much but I still have a few questions. The bedroom is open plane with no doors and the bathroom is on the opposite side to the heater, so I will have to come round the back of the boat to get to the bathroom rad. I was thinking of putting a pump on the end of the circuit turning it self on now and again, this would still allow the bedroom rad to circulate without the pump running. Also I wanted to fit a pressure vassal instead of a header tank, what do you think. Colin.

[blackrose]

That as been a great help, thanks very much but I still have a few questions. The bedroom is open plane with no doors and the bathroom is on the opposite side to the heater, so I will have to come round the back of the boat to get to the bathroom rad. I was thinking of putting a pump on the end of the circuit turning it self on now and again, this would still allow the bedroom rad to circulate without the pump running. Also I wanted to fit a pressure vassal instead of a header tank, what do you think. Colin.

 

If you want the stove on one side of the boat and a bathroom rad (now the final rad) on the other side of the boat, then you'll definately need a pumped system. Whether the bedroom rad can still be run on thermocycling depends on how you plumb it in (as described previously), and I'm assuming your pipework around the back of the boat through the bedroom would then have to go at floor level so you can use the door? In principal there's no reason it this hybrid system wouldn't work with a pump somewhere on that section and the advantage would be that if the pump ever failed you could probably still light the stove. If it's concealed, that final section could be in plastic and all plumbed at floor level to a nice towel rad in the bathroom.

 

You could fit a pressure vessel instead of a header tank - an large accumulator type tank is ideal but I'm just wondering if it should be fitted on the thermocycling part of the system in case the pump ever fails? It should be far enough away from the stove so the water isn't boiling and must be able to handle hot water up to 80 or 90 deg. Also make sure you have a bleed valve at the very top of the pipework.

 

You have a choice of 12v pumps - regular or brushless - the latter are apparently longer lasting, but I've no idea about makes or models. You can either have manual switching of the pump or use thermostats to do this automatically. In your hybrid system I'd imagine manual switching would be fine because if you forget to switch it on it's no big deal. You'll need a switch with a little light so you don't forget to switch it off.

 

Mike

Edited March 1, 2008 by blackrose

[Chris J W]

Here's my experience;

 

Morso on 24/7 right at the front of the boat with an eco-fan, open plan down to the bathroom, followed by bedroom and I've never had to fire up my CH at all. Possibly because the bathroom door has a gap top and bottom to allow warm air to enter and leave but even that's warm enough even with leaving the door closed.

[blackrose]

Here's my experience;

 

Morso on 24/7 right at the front of the boat with an eco-fan, open plan down to the bathroom, followed by bedroom and I've never had to fire up my CH at all. Possibly because the bathroom door has a gap top and bottom to allow warm air to enter and leave but even that's warm enough even with leaving the door closed.

 

Sounds a lot simpler to me! (How long's your boat & do you mean your CH is a separate diesel-fired system?)

 

The other factor to take into account is how well insulated the boat is. If it is you might be able to get away with an eco-fan and none of this backboiler/radiator malarky.

Edited March 1, 2008 by blackrose

[colin loach]

Well that’s put the cat amounts the pigeons, my boat is spray foam insulation. How long is your boat, and dose it get warm all over. Colin.

[Chris J W]

Sounds a lot simpler to me! (How long's your boat & do you mean your CH is a separate diesel-fired system?)

 

The other factor to take into account is how well insulated the boat is. If it is you might be able to get away with an eco-fan and none of this backboiler/radiator malarky.

 

She's a 57ft, with about 1/2 to 3/4inch sprayfoam insulation. Given the size of the well deck and the space taken up with the engine hole, there's probably about, say, 45ft of space to be heated. Once the stoves going well I'd say there's only a few degrees difference from bow to stern, and even leaving on tick-over overnight the bedroom in the stern is still comfortable in the morning.

 

The CH is an Eberspacher that would drive three rads (one bedroom, bathroom and passage) if I ever turned it on.

Edited March 1, 2008 by Chris J W

[blackrose]

She's a 57ft, with about 1/2 to 3/4inch sprayfoam insulation. Given the size of the well deck and the space taken up with the engine hole, there's probably about, say, 45ft of space to be heated. Once the stoves going well I'd say there's only a few degrees difference from bow to stern, and even leaving on tick-over overnight the bedroom in the stern is still comfortable in the morning.

 

The CH is an Eberspacher that would drive three rads (one bedroom, bathroom and passage) if I ever turned it on.

 

I'd run the Erberspacher at least once a week for an hour even if you don't need it, just to maintain it Chris. That's providing your batteries are well charged. That's the advice I was given a few years ago and it seems to have worked (touch wood). I use mine to get some quick heat into the boat on cold mornings and to get some hot water, or when I come home late to heat the boat while I'm getting the stove going.

 

Quite a few people have diesel heaters like webastos & erbaspachers in their boats these days as well as solid fuel stoves Colin, but they're a luxury really, not essential.

Edited March 2, 2008 by blackrose

[Jparry]

That as been a great help, thanks very much but I still have a few questions. The bedroom is open plane with no doors and the bathroom is on the opposite side to the heater, so I will have to come round the back of the boat to get to the bathroom rad. I was thinking of putting a pump on the end of the circuit turning it self on now and again, this would still allow the bedroom rad to circulate without the pump running. Also I wanted to fit a pressure vassal instead of a header tank, what do you think. Colin.

It is considered dangerous to use a solid fuel stove on a sealed system ,adding a pressure vessel instead of a header tank would make it a sealed system they dont consider solid fuel controllable enough.Joe

[Chris J W]

I'd run the Erberspacher at least once a week for an hour even if you don't need it, just to maintain it Chris. That's providing your batteries are well charged. That's the advice I was given a few years ago and it seems to have worked (touch wood). I use mine to get some quick heat into the boat on cold mornings and to get some hot water, or when I come home late to heat the boat while I'm getting the stove going.

 

Ta for that. Normally being on her all the time (on the beach at the mo ) it's never really crossed my mind bar using the control in the bedroom to see what time it is. Not a bad idea, though, so I think I'll start giving it a run as suggested - may even try it when I get back on Thursday as it'll be bloody cold in there by now!

[colin loach]

Thanks to everyone, I think I will try the heater on its own, if its not good enough I will add another heater later. I had a propex on my dawn craft and that was pretty good, and very easy to fit. Thank again. Colin.

[sueb]

Here's my experience;

 

Morso on 24/7 right at the front of the boat with an eco-fan, open plan down to the bathroom, followed by bedroom and I've never had to fire up my CH at all. Possibly because the bathroom door has a gap top and bottom to allow warm air to enter and leave but even that's warm enough even with leaving the door closed.

 

We had this set up on our last boat and I froze in the bathroom. We now have from back - califorfyer (you know what I mean) kitchen - rayburn- living room- bathroom with double rad- bedroom with double rad. It all works by thermo watsit with no pump. 58' boat

Sue

[colin loach]

We had this set up on our last boat and I froze in the bathroom. We now have from back - califorfyer (you know what I mean) kitchen - rayburn- living room- bathroom with double rad- bedroom with double rad. It all works by thermo watsit with no pump. 58' boat

Sue

Sue has your boat been spray foam insulated.

[sueb]

Sue has your boat been spray foam insulated.

 

Yes. Had boat about 18yrs now

Sue

[chris w]

Yes. Had boat about 18yrs now

Sue

 

I don't think spray-foam was around that long ago. Have you had it done since you bought the boat?

 

Chris

[Dylan]

I don't think spray-foam was around that long ago. Have you had it done since you bought the boat?

 

Chris

That's an interesting one: I am trying to recall when I first encountered spray foam in a narrowboat. I can say that it was used on road tankers at a company that I was involved with from 1980 onwards. It has also been applied to the inside of slate roofing for quite a few years now.

[wonderdust]

We have been using it since mid 80s but it was bl**dy expensive, don't know when it started being used in nb's.

Edited March 2, 2008 by wonderdust

[sueb]

I don't think spray-foam was around that long ago. Have you had it done since you bought the boat?

 

Chris

Yes we bought the boat first.

Sue

[blackrose]

It is considered dangerous to use a solid fuel stove on a sealed system ,adding a pressure vessel instead of a header tank would make it a sealed system they dont consider solid fuel controllable enough.Joe

 

In that case perhaps I was wrong when I said an accumulator tank could be used. In fact I'm not even sure if a sealed pressurised system would work with thermocycling because the pressure might restrict the natural flow of convection & gravity.