Frost protection - Trace heating

[jonesthenuke]

Our boat sits in a marina for most of the winter, however we visit and use it whenever we can even if its cold. Fully draining down all the pipes etc is a time consuming affair but needed to protect against freezing (I am not keen on adding antifreeze to the water supply even if it is supposed to be safe).

 

Even with draining down there is some risk of water being left in pipes and freezing. Consequently we use an oil filled heater on a frost thermostat to maintain some background heating but I am not convinced that this is effective as the items I am trying to protect (calorifier, pipework, pumps etc) are generally behind woodwork and unlikely to feel much benefit from heating the main cabin spaces.

 

I do not want to take the other option of draining at the beginning of the winter and then not using the boat until the warmer weather arrives so am looking to obtain adequate protection whilst minimising the burden at each visit. I am thus considering trace heating of the self regulating tape type. This would be installed in the pipe runs, around the calorifer and the pumps, thus ensuring some direct protection. Such a system would have thermostats to switch on at a few degrees above freezing. As the heating is localised and controlled I judge that less electricity will be used which is another benefit. Clearly I would drain the bulk of the water from the system, leave taps open etc etc, but would spend less time trying to get the last of the water out.

 

Has anyone considered or tried this, if so I would welcome advice.

Thanks

 

[bizzard]

I've on a great many occasions stood at the urinals in freezing cold pub toilets, peering up examining the flushing cistern and all the pipes trace wire' it does seem to work alright as the flushing nozzles always seem to be dribbling. Ahhh! that's better.

[MtB]

This seems like HUGE overkill. When I have a marina mooring I just put a free standing electric heat in the boat set to come ON at about 5 degrees C.

 

MtB

[jonesthenuke]

Why HUGE overkill? Its not that expensive to install and running costs will be lower.

 

I remain far from convinced that my centrally located heater will protect, for example, the domestic water pump which is located in the base of a cupboard at floor level just inside the front doors Almost certainly OK in normal conditions but what about extreme conditions when ice forms on the canal?

 

If there is positive experience that this is going to be ok then that's fine, it is precisely why I posted the issue to see what those with more experience think.

[system 4-50]

It works for me on my country cottage which has an outside electric shower (don't ask) but I've not tried it in a boat. I suspect it comes on about 5 degrees so it is liable to be on quite a lot.

[DHutch]

It would be an amount of work to retro-fit, but if designing a boat for intermittent all year round use it would pay for itself in no time.

 

-Its the right thing for the job if you ask me.

 

 

Daniel

[blackrose]

Why HUGE overkill? Its not that expensive to install and running costs will be lower.

 

I remain far from convinced that my centrally located heater will protect, for example, the domestic water pump which is located in the base of a cupboard at floor level just inside the front doors Almost certainly OK in normal conditions but what about extreme conditions when ice forms on the canal?

 

If there is positive experience that this is going to be ok then that's fine, it is precisely why I posted the issue to see what those with more experience think.

I think you'll be fine with your oil filled rad. I used a single oil filled radiator 2 winters ago when I had to leave the boat for several months and it got down to -5 or -6C. My pipes are also behind woodwork and I didn't even drain them down. I just switched the water pump off, isolated the tank, opened a couple of taps and drained my gas water heater as that appliance is vulnerable. The heater was set at the lowest power setting (1kw) at 6C on the thermostat. This was on a big widebeam.

Edited November 27, 2014 by blackrose

[Arthur Brown]

Given access to the pipe work then trace heating with 5C froststat is the perfect answer. If you don't have access then an oil filled radiator is probably easier.

 

Trace heating will do the job on about 200w of mains, an oil filled heather will be 1000w typically.

 

Whether you use trace or oil filled the froststat is important.

 

At home I drop a small fish tank heater in the cold header tank water as it's cheaper than a new ceiling, (it's in the loft).

[nicknorman]

Our previous house had a hot water pipe running outside to get to the kitchen. Although it was insulated, being in Scotland it still froze from time to time. I installed trace heating of the semiconducting (ie self-regulating) type, starts to conduct around 5C. Worked really well, but of course you have to put pipe insulation over the whole lot. No thermostat required as it intrinsically senses the temperature under the insulation, not the room temperature. I think this will be much more economical than using a room stat.

 

Eventually I moved the pipe inside!

 

I used the same stuff when we built the gliding club's clubhouse. This is near Aviemore in the Cairngorms and can be a very cold place in the winter (-27C recorded in Braemar, about 20 miles away, one year). The clubhouse is unoccupied and unheated during the week. We have never had a frozen pipe in the 14 years since I installed it.

[MtB]

Given access to the pipe work then trace heating with 5C froststat is the perfect answer.

 

 

No it isn't!

 

How will trace heating protect a Morco water heater heat exchanger for example? Or shower mixer brass castings? Or even a plastic water pump? And how are you going to trace-heat a foam insulated calorifier?

 

Far better (and far easier) to use a space heater or two to keep the interior just above 0 degree C, in my opinion.

 

And opinions are what the OP requested!

 

 

MtB

 

 

 

(Edit for clarirty)

Edited November 28, 2014 by Mike the Boilerman

[nicknorman]

No it isn't!

 

How will trace heating protect a Morco water heater heat exchanger for example? Or shower mixer brass castings? Or even a plastic water pump? And how are you going to trace-heat a foam insulated calorifier?

 

Far better (and far easier) to use a space heater or two to keep the interior just above 0 degree C, in my opinion.

 

And opinions are what the OP requested!

 

 

MtB

 

 

(Edit for clarirty)

I don't think OP was suggesting leaving the system totally intact. Things like a Morco (which he doesn't mention having) are surely easily drained since they are high up, with taps below them. Ditto shower mixer. Our pump is easily removed for draining but I have taken to just disconnecting the inlet and running it for a bit to pump air through. Of course this still leaves lots of water in the low points but I have the backup cunning plan of being able to keep an eye on the weather and turn on the Mikuni from Scotland if necessary. Since we got the boat in 2011 the winters have been pretty mild so have not needed to do that yet.

[MtB]

I don't think OP was suggesting leaving the system totally intact. Things like a Morco (which he doesn't mention having) are surely easily drained since they are high up, with taps below them. Ditto shower mixer. Our pump is easily removed for draining but I have taken to just disconnecting the inlet and running it for a bit to pump air through. Of course this still leaves lots of water in the low points but I have the backup cunning plan of being able to keep an eye on the weather and turn on the Mikuni from Scotland if necessary. Since we got the boat in 2011 the winters have been pretty mild so have not needed to do that yet.

 

Th OP seemed to be looking for a solution that specifically doesn't involve draining down. Once you do this there is no need for the trace heating either!

 

On the Morco I'd be interested to hear a quick and un-messy way of draining one. They don't have handy drain cocks like a Paloma. I drain mine currently by using a stirrup pump to pump air into the system and water out. Then if I'm feeling very fussy I disconnect the Speedfit couplings under it and try to catch any remaining water spilling out. Quite a faff if you are in a hurry to leave the boat.

 

And easy to forget you've done on returning and turning the power back ON!

 

MtB

[nicknorman]

Th OP seemed to be looking for a solution that specifically doesn't involve draining down. Once you do this there is no need for the trace heating either!

 

On the Morco I'd be interested to hear a quick and un-messy way of draining one. They don't have handy drain cocks like a Paloma. I drain mine currently by using a stirrup pump to pump air into the system and water out. Then if I'm feeling very fussy I disconnect the Speedfit couplings under it and try to catch any remaining water spilling out. Quite a faff if you are in a hurry to leave the boat.

 

And easy to forget you've done on returning and turning the power back ON!

 

MtB

Ok well I never had a Morco, but if I did surely it would be easy to install a T and a service valve (not connected to anything, ie a drain) in the plumbing near the Morco? Or does the water decline to drain out of the heat exchanger under gravity? Anyway, slightly academic since OP doesn't gave a Morco. Alternatively do as I do and disconnect the main pump inlet, turn it on and pump air through the system. I do this and turn on the washing machine briefly to purge water out if the plastic inlet solenoid valve, ditto for the loo and shower thermostatic mixer. It only takes seconds to do with plastic plumbing.

[jonesthenuke]

I don't think OP was suggesting leaving the system totally intact. Things like a Morco (which he doesn't mention having) are surely easily drained since they are high up, with taps below them. Ditto shower mixer. Our pump is easily removed for draining but I have taken to just disconnecting the inlet and running it for a bit to pump air through. Of course this still leaves lots of water in the low points but I have the backup cunning plan of being able to keep an eye on the weather and turn on the Mikuni from Scotland if necessary. Since we got the boat in 2011 the winters have been pretty mild so have not needed to do that yet.

To add some information to the Original Post;

• We do not have a Morco or similar the heating is from a Hurricane which is OK as its system is dosed with antifreeze.
• I am looking for an arrangement where we can leave the boat after completing a brief drain of the system, but I want to minimise the time this takes, the point being to maximise the "use" of the boat in winter. So, isolating water at the pump and pushing air through, leaving taps and shower valve open etc is fine but I would like to avoid more extensive and time consuming activities which I currently undertake.
• I judge trace heating the calorifier to be practicable even with foam lagging. Ours is located below the main bed and is boxed in. A loop of trace heating around the base will keep the local temperature above zero. This strikes me as more likely to be effective than a heater for the bulk of boat.
• I accept this may take some time to install and involve some cost. This is OK as I will do the work myself over time and currely I see the likely cost as being reasonable.

Thanks for the replies so far.

[Phil Ambrose]

I'm confused about adding anti freeze to the domestic water, I always thought it was poisonous.

Phil

[Alan de Enfield]

We have trace-heating on the caravan park.

 

You need free and easy access to the full length of the pipe, if you have plastic pipe (which I guess most of us have) you need to apply an adhesive backed aluminium foil to protect the plastic pipe (the heating cable can/will damage plastic pipe)

 

Depending on the type of cable you will be using you need to either wrap the foil & cable spirally along the length of the pipe (in which case you need sufficient room to pull the pipes away from the wall/floor) or the foil & cable are laid longtitudinally.

 

Once installed the whole system must be encased in foam pipe insulation. This means the 'grey foam' with a slit in it. Due to the additional size of the cable on the pipe, this makes the slit in the foam ' bag-open' and you need to warp insulating tape every few inches to hold it closed. You obviously need enough 'slack'/movement in your pipes to be able to fit the insulation.

 

Heat trace cable will not protect an insulated calorifier.

 

Dont bother with the 11 watts per metre - its not enough and will be 'running' continuously.

20 or 30 watts per metre works well.

 

You can buy 12 volt trace cables and up to 300 watt per metre

I'm confused about adding anti freeze to the domestic water, I always thought it was poisonous.
Phil

 

Its OK in wine

 

(Or it was a few years ago)

[Naughty Cal]

We have never drained down our boat. We rely on small oil filled rads, one large tube heater in the engine bay, a smaller tube heater in the shower room and a 600 watt rad in the cabin area. We leave these on 24/7 as we have had bad experiences in the past with the thermostatic switches. We have not had any problems yet although this year will be the first that NC has spent all winter ashore and boats get colder ashore so only time will tell if it will be adequate protection this winter.

[Southern Star]

I'm confused about adding anti freeze to the domestic water, I always thought it was poisonous.

Phil

http://www.elsan.co.uk/anti-freeze.aspx

[system 4-50]

My belief is that trace heating will protect the pipe that is taped and a certain length of un-taped pipe beyond that provided that it is rising so that warmed water will rise up into it. This only works for a limited length and depends on the degree of insulation so it might work for a Morco for a small amount of chill and it might not. It won't work if the pipe is not full of water or runs downhill.

[John V]

Thanks for that link Southern Star.....I didn't know you could get a non-poisonous antifreeze either !!!

[dor]

but I want to minimise the time this takes, the point being to maximise the "use" of the boat in winter. So, isolating water at the pump and pushing air through, leaving taps and shower valve open etc is fine but I would like to avoid more extensive and time consuming activities which I currently undertake.

 

This is pretty much all we do. It has survived two winters that went down to less than -15C without problems. The calorifier sits on the swim and that seems to keep it from freezing, even with several inches of ice.

[Kendal]

I think you'll be fine with your oil filled rad. I used a single oil filled radiator 2 winters ago when I had to leave the boat for several months and it got down to -5 or -6C. My pipes are also behind woodwork and I didn't even drain them down. I just switched the water pump off, isolated the tank, opened a couple of taps and drained my gas water heater as that appliance is vulnerable. The heater was set at the lowest power setting (1kw) at 6C on the thermostat. This was on a big widebeam.

I am considering a couple of oil filled rads on a thermostat for this winter, powered from a hook up in the marina (we don't live aboard). I am slightly concerned about leaving the boat for a week or two at a time with the power on. Am I worrying unduly? I have checked the insurance conditions if the worst happened and I think it would be covered. Not sure about the marina conditions though, will have a look later.

[MtB]

I'm confused about adding anti freeze to the domestic water, I always thought it was poisonous.

Phil

 

 

The non-poisonous stuff isn't...

 

 

MtB

[MtB]

Ok well I never had a Morco, but if I did surely it would be easy to install a T and a service valve (not connected to anything, ie a drain) in the plumbing near the Morco? Or does the water decline to drain out of the heat exchanger under gravity?

Mine declines to drain unless I disconnect both the inlet and outlet pipes. I have Speedfit fittings but it is still quite a faff to do. And on more than one occasion I've forgotten I've done it when turning the water back ON! I might try installing some quarter turn valves to open instead but I'm not convinced they will work.

 

 

 

Alternatively do as I do and disconnect the main pump inlet, turn it on and pump air through the system. I do this and turn on the washing machine briefly to purge water out if the plastic inlet solenoid valve, ditto for the loo and shower thermostatic mixer. It only takes seconds to do with plastic plumbing.

 

Interesting! It never occurred to me that a water pump would pump fresh air and develop enough pressure to expel water from the pipes ahead of it. I'll try it. If mine does this all I'll need is a tee in the supply pipe at the pump inlet and a quarter turn valve to open to let the air in! Thanks!

 

 

MtB

 

 

 

(Edit to fix my messed up HTML, AGAIN!)

Edited November 28, 2014 by Mike the Boilerman

[Canalwatcher]

 

 

The non-poisonous stuff isn't...

 

 

MtB

It's called Freezeban

 

http://www.marinemegastore.com/product-product-AFX_9_90760.htm

 

Mick

Edited November 28, 2014 by zodiak