Hot tank draining

[floatingphil]

Hi

 

Another tech question I’m afraid, I want to be able to drain my hot and cold water tanks quickly if we get bad cold snap.I have no drain tap on the hot tank so im gonna fit one. I use the boat during the winter just for days out. If the hot tank is drained and the eberspatcher and the engine heat the tank without water in it, will this cause a problem? I.e. will I need to fill the hot tank every time I use the boat? When it comes to lagging, is this worth while on a boat or not?

 

 

Many thanks

Phil

[cotswoldsman]

Hi

 

Another tech question I’m afraid, I want to be able to drain my hot and cold water tanks quickly if we get bad cold snap.I have no drain tap on the hot tank so im gonna fit one. I use the boat during the winter just for days out. If the hot tank is drained and the eberspatcher and the engine heat the tank without water in it, will this cause a problem? I.e. will I need to fill the hot tank every time I use the boat? When it comes to lagging, is this worth while on a boat or not?

 

 

Many thanks

Phil

 

Dont understand why you need to drain the tanks. OK if you want drain water tank to 3/4 full and if you want drain the pipes but surely your hot water thingy has lagging.

[blackrose]

Hi

 

Another tech question I’m afraid, I want to be able to drain my hot and cold water tanks quickly if we get bad cold snap.I have no drain tap on the hot tank so im gonna fit one. I use the boat during the winter just for days out. a: If the hot tank is drained and the eberspatcher and the engine heat the tank without water in it, will this cause a problem? I.e. will I need to fill the hot tank every time I use the boat? b: When it comes to lagging, is this worth while on a boat or not?

Many thanks

Phil

 

a: Yes - you will overheat the coils inside the calorifier.

 

b: If your calorifier has an inch or more of PU foam on it already then probably not.

 

It would have to be VERY cold to freeze either your fresh water tank or your calorifier because they contain large volumes of water. It's much more likely that pipes containing small volumes of water will freeze, so it's a good idea to switch off the water pump and open the taps. This may give any freezing water somewhere to expand - depending on which bit freezes first.

 

It's a good idea to switch off your water pump and perhaps close the main isolator from your cold water tank every time you leave the boat whatever the weather. If for some reason a pipe springs a tiny leak and you've left the water pump on, the pressure switch in the pump will just sense the pressure drop in the system - the same as you opening a tap and it will pump water into your bilges until the tank is empty. Then it will continue to cycle until it has burned itself out. (If the same thing happened while you were onboard then you'd hear the pump cycling for no reason and could investigate - but if you're not there you're screwed).

Edited December 1, 2009 by blackrose

[cotswoldsman]

It's a good idea to switch off your water pump and perhaps close the main isolator from your cold water tank every time you leave the boat whatever the weather. If for some reason a pipe springs a tiny leak and you've left the water pump on, the pressure switch in the pump will just sense the pressure drop in the system - the same as you opening a tap and it will pump water into your bilges until the tank is empty. Then it will continue to cycle until it has burned itself out. (If the same thing happened while you were onboard then you'd hear the pump cycling for no reason and could investigate - but if you're not there you're screwed).

 

That is a very good point about switching off pump when away I had a flood on my boat caused by pump pumping water through a leak. I now switch mine off whenever I leave boat but for me that is easy as I have to walk past control board to get off boat so just like switching off lights.

[nb Innisfree]

a: Yes - you will overheat the coils inside the calorifier.

 

b: If your calorifier has an inch or more of PU foam on it already then probably not.

 

It would have to be VERY cold to freeze either your fresh water tank or your calorifier because they contain large volumes of water. It's much more likely that pipes containing small volumes of water will freeze, so it's a good idea to switch off the water pump and open the taps. This may give any freezing water somewhere to expand - depending on which bit freezes first.

 

It's a good idea to switch off your water pump and perhaps close the main isolator from your cold water tank every time you leave the boat whatever the weather. If for some reason a pipe springs a tiny leak and you've left the water pump on, the pressure switch in the pump will just sense the pressure drop in the system - the same as you opening a tap and it will pump water into your bilges until the tank is empty. Then it will continue to cycle until it has burned itself out. (If the same thing happened while you were onboard then you'd hear the pump cycling for no reason and could investigate - but if you're not there you're screwed).

 

Can't see any problem with an empty cylinder, coil won't overheat, it will get no hotter than if cyl is full and up to max temp. True it will heat up quicker but I can see no harm in that.

[AndyM]

Hi

 

Another tech question I’m afraid, I want to be able to drain my hot and cold water tanks quickly if we get bad cold snap.I have no drain tap on the hot tank so im gonna fit one. I use the boat during the winter just for days out. If the hot tank is drained and the eberspatcher and the engine heat the tank without water in it, will this cause a problem? I.e. will I need to fill the hot tank every time I use the boat? When it comes to lagging, is this worth while on a boat or not?

 

 

Many thanks

Phil

 

Ran the calorifier connected to the engine for quite some time before the fit out was at the stage to fill the domestic system with water, no harm done to the calorifier at all.

 

I connected a sureflow pump to the drain on both the hot and cold to aid a quick drain of the system in winter but have not used this for the past two years without any damage to the pipework or the calorifier. The calorifier is well lagged with spray foam and I patched the fitted piping and joints with this too. The majority of pipework is Hep20 with foam insulation on.

 

Andy.

[Tony Brooks]

Can't see any problem with an empty cylinder, coil won't overheat, it will get no hotter than if cyl is full and up to max temp. True it will heat up quicker but I can see no harm in that.

 

 

The plumber lecturers at TVU assured me that the expansion and contraction of calorifier coils and engine vibration without water to support them could cause the coils to fail.

 

My experience on the hire fleet is that, depending upon the internal "coil" design, horizontal ones sometimes have poorly supported inner parts when compared with vertical one and it was always horizontal ones that failed. Vertical ones never did.

 

If the horizontal ones has a coil inside it rather than a sort of double walled tube then I doubt you will have any trouble and I am confident you will be OK with a vertical one.

 

I am not so sure about or have experience of the expensive ones (of either type) that use very thin wall crimped coil pipes for faster heat transfer. I would not run one of these without water to help support and damp any vibrations on the coil.

[floatingphil]

Yes my thoughts were that I could damage the coils. Think I may leave it as it is, I always knock the pump off and shut the gate valve on the cold tank when I leave. Wonder why so many bang on about winterisation then? Maybe i should lag the pipes although I can,t easily access them all

 

Thanks for your advices, can we talk Formula one on this site ?

 

Phil

[ditchcrawler]

Yes my thoughts were that I could damage the coils. Think I may leave it as it is, I always knock the pump off and shut the gate valve on the cold tank when I leave. Wonder why so many bang on about winterisation then? Maybe i should lag the pipes although I can,t easily access them all

 

Thanks for your advices, can we talk Formula one on this site ?

 

Phil

Come January I shall drain my calorifier and all the pipe work. I plumbed in with a drain to the shower emptying pump via a valve. I shall also disconnect the pump and make sure the water is out of it. 30 minutes work maybe.

Next time I come to the boat I just open the gate valve from the storage tank and start the pump. The system will be full again and ready to go in under 10 minutes.

If we have a hard freeze with say 6" ice on the cut I don't want to lose my cylinder or pump

[alan_fincher]

Dont understand why you need to drain the tanks. OK if you want drain water tank to 3/4 full and if you want drain the pipes but surely your hot water thingy has lagging.

I always struggle on this point, which I know has been much debated previously.

 

I am assuming the case of a non live-aboard, who does not leave a boat heated in any way, and may not go back for some weeks.....

 

Lagging on anything, (including the calorifier), will no doubt slow down the rate at which it cools if temperatures drop. However all insulation can do is slow down a rate of cooling, not stop it, so if temperatures inside the boat did manage to go seriously sub-zero for a prolonged period, I would argue that eventually pipes, then even the calorifier could freeze.

 

Also don't forget that lagging will stop something very cold heating up again anything like as fast if ambient temperatures rise, so could actually be counter-productive in that case.

 

That said, many people do seem to leave them in a completely cold boat with no damage, (whilst some report they have had damage...).

 

The jury is still out for me. I'm sufficiently convinced that an instantaneous water heater can damage that I will drain that. I think pipes can, so if I'm good, I at least leave taps open. So far since fitting a calorifier I've not drained that, but it has only been in one winter, so perhaps not a definitive test.

 

I think if the boat has some background heat, or you live on it, then nothing is required, but left stone cold for weeks at a time, I'm really not that confident.

 

I'd be interested what plumbing and or tank failures people have actually experienced in unattended, unheated boats, (but not in hearing that if you live on them, all will be fine - because I can't, full time!).

[floatingphil]

Come January I shall drain my calorifier and all the pipe work. I plumbed in with a drain to the shower emptying pump via a valve. I shall also disconnect the pump and make sure the water is out of it. 30 minutes work maybe.

Next time I come to the boat I just open the gate valve from the storage tank and start the pump. The system will be full again and ready to go in under 10 minutes.

If we have a hard freeze with say 6" ice on the cut I don't want to lose my cylinder or pump

 

 

mm thats the reason i was going to fit a drain valve on the calorifer. At the moment there is nothing and means disconnection at the pump which is messy and difficult to get to unless your double jointed. Funny really, my last midlife crisis toy was a Westfield sportcar and you needed double joints to work on that too

 

I think i will stick a drain valve on the calorifer anyway. worth having even if i dont use it much

 

Phil

[Ray]

How do you drain the calorifier if it has an inbuilt non return valve on the cold water supply connection?

[Chertsey]

I'm sufficiently convinced that an instantaneous water heater can damage that I will drain that.

 

It certainly can and mine did.

[Keeping Up]

I'd be interested what plumbing and or tank failures people have actually experienced in unattended, unheated boats, (but not in hearing that if you live on them, all will be fine - because I can't, full time!).

The first winter we left our boat unattended and unheated, with all the taps open. The calorifier tank, which is vertical and inside the boat expanded and bulged out to a hemisphere at the bottom like a giant Weeble.

[Neil TNC]

Come January I shall drain my calorifier and all the pipe work. I plumbed in with a drain to the shower emptying pump via a valve. I shall also disconnect the pump and make sure the water is out of it. 30 minutes work maybe.

Next time I come to the boat I just open the gate valve from the storage tank and start the pump. The system will be full again and ready to go in under 10 minutes.

If we have a hard freeze with say 6" ice on the cut I don't want to lose my cylinder or pump

 

We went out last night at 19:30 to drain down Linda's Wilderness. Rather important as the Rinari was still full.

Mini Me is still in the water as Linda wanted to have one last go, before probable carting off to Ian Graham for sale.

That looks unlikely now.

 

Even with a drain cock open and all the taps open and PRV lifted (with a forked bit of metal) I could still not get Earnest's vertical calorifier to empty (I even had drain going under floor, and into an old tray, where I could bung the auto dry bilge pump)

So... this year I used the new 12v diesel vane pump I had just bought. That got the water out!

[floatingphil]

We went out last night at 19:30 to drain down Linda's Wilderness. Rather important as the Rinari was still full.

Mini Me is still in the water as Linda wanted to have one last go, before probable carting off to Ian Graham for sale.

That looks unlikely now.

 

Even with a drain cock open and all the taps open and PRV lifted (with a forked bit of metal) I could still not get Earnest's vertical calorifier to empty (I even had drain going under floor, and into an old tray, where I could bung the auto dry bilge pump)

So... this year I used the new 12v diesel vane pump I had just bought. That got the water out!

 

 

All done, drain tap fitted, water didnt come gushin out as i expected. All ready for global warming now!

 

Thanks everyone for your help

 

Phil

[WotEver]

The calorifier tank, which is vertical and inside the boat expanded and bulged out to a hemisphere at the bottom like a giant Weeble.

At least it wouldn't fall down.

 

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