Draining all potable water from boat

[Adam1991]

Hi, since there’s frost on the way tonight and we are not using our boat to live on yet I would like to drain all the water from the system. 
 

Am I right in think just opening all the hot and cold taps and letting them run will drain the whole system? 
 

Will this put strain on the jabsco pump to drain it all away in one go?
 

I can’t drain the calorifier manually from the drain spigot on the tank as it’s not plumbed overboard. 
 

cheers! 

[Jen-in-Wellies]

13 minutes ago, Adam Mc Gowan said:

Am I right in think just opening all the hot and cold taps and letting them run will drain the whole system? 

Mostly. Apparently shower mixer valves and gas heater matrices are particularly vulnerable and can have water left inside from a simple pump through, which can lead to damage. Since I don't have either on my boat, I can't say more.

13 minutes ago, Adam Mc Gowan said:

Will this put strain on the jabsco pump to drain it all away in one go?

No.

13 minutes ago, Adam Mc Gowan said:

I can’t drain the calorifier manually from the drain spigot on the tank as it’s not plumbed overboard. 

Mines the same. On the couple of occasions I've done it, buckets were involved to take the water from cauliflower to sink. Being a large volume of water it takes longer to cool down to below freezing, so if the 24hr average is still >0, I wouldn't bother. Same for the water tank. The presence of the canal around the boat also moderates extreme temperature swings.

Boats are pretty resistant to cold. On occasion, I've left mine in a few degrees of frost for a few days with the pump off and the taps open to allow expansion. Plastic plumbing is more resistant to frost than metal.

Should I recommend turning the boat upside down to shake out the last of the water? No, that would be naughty. 😀

Edited March 7, 2023 by Jen-in-Wellies

[Tony Brooks]

You will leave a lot of water in the pipes by just draining via the taps, but so do most of us and most winters there is no problem as long as you leave the taps open, especially with plastic pipes. Occasionally a connector will push ff. but it has never happened to me.

 

Definitely take the shower mixer off and ensure it is free of trapped water.

 

I would keep the battery charging while you drain via the pump. I have never had a  problem with water pumps while doing this.

 

Calorifier - hose and drill pump it overboard. However, in the end I did not bother and suffered no frost damage - the canal water is warm a few inches down, even with ice on the canal. This was in the Napton area, and one winter the boat froze solid in the ice.

[Adam1991]

Hi Jen, thanks! Will make sure not to tip it upside down to get the water out 😂

 

do you know if there is a way to drain the pipework without draining the tank? 

[Tracy D'arth]

3 minutes ago, Adam Mc Gowan said:

Hi Jen, thanks! Will make sure not to tip it upside down to get the water out 😂

 

do you know if there is a way to drain the pipework without draining the tank? 

Turn off the valve twix tank and pump?  I loosen the inlet of the pump so it can suck air in.

[Lily Rose]

Might not apply to your boat but on mine there is a stop-cock in the pipe about 6 inches from the tank. I turn this off, open the tap until all the water in the pipe has been drained, turn off the pump and leave the tap open before I go home.

 

I suspect it makes no difference as the pipework is well below the waterline but I do it anyway as it's so easy.

 

I have never been able to drain the calorifier so I leave a thermostat-controlled tube heater under it in winter. Unfortunately I didn't put it there when I left the boat 9 days ago as, at the time, tonight was forecast to be +4°C. It's now forecast to be -4°C so I am a bit concerned but probably not enough to do a round trip of nearly two and a half hours to put it back.

 

If Jen is right about the 24 hour average then it should be ok. I hope.

 

 

Edited March 7, 2023 by Lily Rose

[robtheplod]

Does draining the calorifier depend on where it is?  in the engine bay or in the boat itself?   I've not drained ours yet as we pop back to the boat regularly but it is inside the boat which i'm thinking may help?

[Lily Rose]

Just now, robtheplod said:

Does draining the calorifier depend on where it is?  in the engine bay or in the boat itself?   I've not drained ours yet as we pop back to the boat regularly but it is inside the boat which i'm thinking may help?

Good point. If mine was under the bed I wouldn't worry in the slightest. Unfortunately it's in the engine room of my trad-stern boat so it loses warmth quite quickly even though I have a hot water cylinder jacket wrapped around it on top of its own insulation. How soon it would freeze enough to cause a problem I just don't know. I'm hoping that one night of temperatures in the low (negative) single figures won't see enough ice forming to cause a problem.

[philjw]

If you have a filter going to a third tap at the sink and it is the kind that has an element inside a housing then its worth draining this. They are usually highish in the boat so don't get any benefit from the warmer water in the cut and retain a thin layer of water between the element and casing.  I lost a casing to frost once - the only damage I have had in 40 years.  I also drain the washing machine by removing the cover of the drain filter.

[blackrose]

I don't normally need to winterise my boat because I live aboard, but when I do go away I isolate the water tank, switch the pump off and open a couple of taps to relieve the pressure in the system. If I go away for a longer period over winter should I drain the calorifier? There is a NRV in the cold feed pipe to the calorifier but if I'm leaving a hot tap open have I reduced the pressure in the calorifier and don't need to bother draining it? I can drain it fairly easily. 

 

Also do most people drain integral water tanks, leave them at a low level or just leave them at whatever level they happen to be at regardless?

[Tonka]

I was told to leave the water tank 1/2 to 3/4 full. Tank valve off, taps open, drain valve's drained. And the hot water tank drained. This has worked for me

[rusty69]

19 minutes ago, blackrose said:

If I go away for a longer period over winter should I drain the calorifier?

If you want to be certain, then the answer is yes. However, a lot will depend on where it is located, and possibly if it is horizontal or vertical. The one on our (other NB) has not been drained in 20 years, and has been ok over some quite cold winters.

[blackrose]

Ok thanks, I will drain it then. I don't think I'm going to try to suck all the residual water out the pipework with a wetvac. That sounds like too much hassle and might possibly damage something like accumulator bladder, NRVs, etc.

[jonathanA]

I don't drain the cauliflower, but its under the bed so quite well protected. I do have a drain off point for the cold water pipework and as others have said leave the taps open (including shower so no water in mixer).  cold water tank left less than full so room for any ice to expand.   Tank valve off.  

 

this regime takes about 10 mins when leaving the boat and about 5 when returning - close taps, open valve, turn on pump, listen for pump switching off - all is well.  get on with boating/life.....

 

couldn't be doing with the faff that some go through. it would be worth the cost of a cauliflower every 20 years or so just to avoid the hassle... 

 

[rusty69]

You could always stick antifreeze (potable) in it. 

Edited July 17, 2023 by rusty69
Add potable

[blackrose]

58 minutes ago, jonathanA said:

couldn't be doing with the faff that some go through. it would be worth the cost of a cauliflower every 20 years or so just to avoid the hassle... 

 

Except if the calorifier does freeze and crack it's potentially not just the cost of a new calorifier that we're talking about. It might also be the cost of some water damage. I wouldn't bother if I was only going away for a couple of weeks and the forecast didn't seem too bad, but if I was leaving the boat for the whole winter draining the calorifier seems sensible and only takes me 20 mins.

58 minutes ago, rusty69 said:

You could always stick antifreeze (potable) in it. 

 

I didn't know such stuff existed?

[rusty69]

18 minutes ago, blackrose said:

I didn't know such stuff existed?

It does, but I've never used it. I think I would be happier draining the calorifier personally.

 

https://www.asap-supplies.com/domestic-water-supply/domestic-antifreeze

[blackrose]

Presumably you pour it into your freshwater tank and pump it though the system by opening some taps, shower, etc. In which case I can't see how it's possible to use it in a fresh water system without diluting it? Unless you use an an awful lot of it I suppose...

 

[rusty69]

It's probably meant for smaller systems like motor homes or small boats.

[GUMPY]

I've never fly drained the system.

Turn off the stop cock, open taps until no water comes out, turn off the pump 

That's it🤔

However I did leave two 700watt rads one near the calorifier and one in the engine area. These were on an external thermostat set at 4deg. There was also a system that sent me a txt message if the temp dropped below 2deg which it only did once in 4 years when the shore power went off,  so I remotely fired up the Eber for a couple of hours.

Edited July 17, 2023 by GUMPY

[David Mack]

An insulated calorifier set low down in an insulated boat cabin is very unlikely to freeze unless the ice on the canal is several inches thick, as the baseplate is in contact with water which is above freezing point, and that will keep the inside air from getting any colder (unless you have sprayfoamed the baseplate). Same might not be true of a calorifier located in an uninsulated stern engine bay, which will be in much more thermal contact with the surrounding air.

[Machpoint005]

One particularly cold winter, the cupful of water in the J-trap under the sink froze, and the pipe split.

 

In contrast, the cauliflower hadn't been drained down, and it didn't freeze.

 

This seems to support what David says above.

 

[cuthound]

4 hours ago, GUMPY said:

I've never fly drained the system.

Turn off the stop cock, open taps until no water comes out, turn off the pump 

That's it🤔

However I did leave two 700watt rads one near the calorifier and one in the engine area. These were on an external thermostat set at 4deg. There was also a system that sent me a txt message if the temp dropped below 2deg which it only did once in 4 years when the shore power went off,  so I remotely fired up the Eber for a couple of hours.

 

This is what I do, but I put one of the heaters by the calorifier and one in the galley because the water pumps live under a cupboard there.

 

I also seal the vents and use a dehumidifier, because after my first winter of leaving windows open we head some doors on the galley cupboards swell and stick.

 

Since then no problems at all, but of course you need shore power.

[blackrose]

4 hours ago, GUMPY said:

I've never fly drained the system.

Turn off the stop cock, open taps until no water comes out, turn off the pump 

That's it🤔

However I did leave two 700watt rads one near the calorifier and one in the engine area. These were on an external thermostat set at 4deg. There was also a system that sent me a txt message if the temp dropped below 2deg which it only did once in 4 years when the shore power went off,  so I remotely fired up the Eber for a couple of hours.

 

I used to do the same and leave thermostatically controlled heating from shore power on a low setting if I was going away during a cold snap, but it's too expensive to do that for any length of time these days. I know burst pipes, etc, are more expensive but that's why I'm looking to take extra precautions.

Edited July 17, 2023 by blackrose

[cuthound]

24 minutes ago, blackrose said:

 

I used to do the same and leave thermostatically controlled heating from shore power on a low setting if I was going away during a cold snap, but it's too expensive to do that for any length of time these days. I know burst pipes, etc, are more expensive but that's why I'm looking to take extra precautions.

 

Tubular heaters are cheaper to run as they are a lower wattage and depending on what and where you are trying to heat can be very cost effective.