Is Your Drain Valve Left Open During Winter ?

Jun 26, 2017
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I gave the van a thorough external cleaning yesterday, and had a potter around inside today in anticipation of the cold snap that some say we should now be expecting.

Just a quick question guys as I’m curious about this one ...

My van’s water system is always drained after every trip, and I leave the the mixer taps open and in the central position, but during the winter when there is the risk of frost, do you keep the drain valve open once all the water has stopped evacuating, or do you close it ? - I’d also be interested to hear the reasoning behind your decision.

Thanks in advance,

Ic.
 

Damian

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Mar 14, 2005
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After draining and blowing out the pipework I leave the drain open to allow an air flow through the pipes and dry them out thus preventing algae having a base to start growing.
 
Oct 3, 2013
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Hello Icarsu5
Our drain valve is opened just before we leave site,this includes the last site visit of the year.The valve is left open all winter and indeed between site visits thoughout the year.and is closed only when we are arriviing at site and filling up with water.
 
Jun 26, 2017
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Thanks Damian. The reason for asking is because I see two possible conflicting trains of thought ...

Leaving the drain valve open means that any last remaining traces of water may make their way out of the system, but it also means that the water system is open to the external elements and the potential that any nasties may have of getting in there.

Leaving the drain valve closed of course isolates the system from the external elements, but may not be the best option just in case there are any last traces of water remaining which could possibly drain out.
 
Jun 26, 2017
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Thanks Bertie.

So it’s 2-0 in favour of keeping the valve open up to now then. Any staunch closers perusing the forum today ?

If it gets to 3-0 before bedtime then I’m going to go into the van and open it ! :p
 
Sep 24, 2008
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On this subject of draining the system down, In the last couple of years we used the vacuum cleaner to extract all the system. So far doing this have not noticed anything wrong but is there any chance of damage to something doing it.
 
Oct 12, 2013
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Hi Lc ,

Our water is dumped & drained as we are leaving the site and every tap in the van opened fully to maximize the amount of water coming out whilst driving back to storage so there should be next to nothing left in the system to freeze , it only gets shut when we are out on our next trip when refilling the system ,
( which will be friday ) :p !!

Craig .
 

Mel

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Mar 17, 2007
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Yes open, and sink and shower taps left open. The more room any residual water has to expand if it freezes, the better.
Mel
 
Mar 14, 2005
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Robert_374373903 said:
On this subject of draining the system down, In the last couple of years we used the vacuum cleaner to extract all the system. So far doing this have not noticed anything wrong but is there any chance of damage to something doing it.
Hello Robert,

On the basis you are only using a domestic vacuum cleaner, then I don't see a problem.
 
Jun 26, 2017
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Thanks Mel,

I totally agree that leaving the drain valve open may help from this perspective, but on the other hand, in doing so, this then exposes rhe system, including the water heater and pump which are situated very close to the drain valve to the ice cold air from outside. Of course the ambient temperature under the front O/S bench where those components are situated is rather cold when the van is out of service in a winter anyway, but I can’t help but think that introducing an icy cold air feed from outside into the to the system could be anything other than detrimental ?
 
Jun 26, 2017
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Thanks Mel,

I totally agree that leaving the drain valve open may help from this perspective, but on the other hand, in doing so, this then exposes rhe system, including the water heater and pump which are situated very close to the drain valve to the ice cold air from outside. Of course the ambient temperature under the front O/S bench where those components are situated is rather cold when the van is out of service in a winter anyway, but I can’t help but think that introducing an icy cold air feed from outside into the the system could be anything other than detrimental ?
 
Mar 14, 2005
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Hello Icaru5

I don't think leaving the pipe work open is a major issue from the temperature perspective. I'd be quite surprised if a significant cold air flow would develop given the tortuous layout of most caravan pipe work, and given that the caravan is in storage and exposed to ambient temperatures. The system should of course be drained, so no water residue should remain to become a problem.

But if the system is fully drained, then closing the system shouldn't be a problem either. It will protect it from insects etc.

I used to drain during the run home from the last outing, when home, check as best one can the system was empty, replace the filter with a blank then close the taps, and close the drain points open. I never suffered any frost damage.

Open or closed its a personal choice, but it is essential the system is drained first.
 
May 7, 2012
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We have always left the drain valve open without problem. i cannot see anything getting in but provided you flush out the system before use if you are laying the caravan up then it should wash out any problem.
 

Mel

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ProfJohnL said:
Hello Icaru5

I don't think leaving the pipe work open is a major issue from the temperature perspective. I'd be quite surprised if a significant cold air flow would develop given the tortuous layout of most caravan pipe work, and given that the caravan is in storage and exposed to ambient temperatures. The system should of course be drained, so no water residue should remain to become a problem.

But if the system is fully drained, then closing the system shouldn't be a problem either. It will protect it from insects etc.

I used to drain during the run home from the last outing, when home, check as best one can the system was empty, replace the filter with a blank then close the taps, and close the drain points open. I never suffered any frost damage.

Open or closed its a personal choice, but it is essential the system is drained first.

Hi Prof. I would absolutely agree that the system should be fully drained, however aceiving this is not straightforward or guaranteed. You can get one of those Floe devices that are intended to remove residual water, but otherwise you have to resort to the more old fashioned methods. Leaving the drain tap open and towing home may shake out residual water, but in my experience there is still water left in the system. (As evidenced by the initial flow from the furthest tap when repriming the system on next use) Also not a lot of use if on a seasonal pitch. Blowing down the shower hose also supposed to help, but you need hefty lungs. Hence, on the basis that there may be water left, despite my best efforts, I go for the taps open to allow for expansion as well.
It had never occurred to me that leaving the drain open will let in either debris or icy air, Icaru, and take your point. However for me the balance of risk still tips me to the taps open model. Interesting debate though.
Mel
 
Jul 18, 2017
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Interesting indeed Mel,seems I may be in the minority,as normal practice for me is(as some also)upon leaving site,drain down via drain valve and taps open,Drive back to storage,then close all taps and valve.Then next time out arrive at site and fill system,and so on.
 
Nov 11, 2009
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I have always opened the taps 50/50, opened the drain valve before leaving the site. They are then left like that until I next pump water into the system.

I also put some screen wash into the flush tank and pump some through the pump. A small quantity also goes down the sink and bathroom drains too.
 
Oct 12, 2013
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Even the odd time I have brought the caravan home and put it on the drive to store it and I have forgotten to open maybee the bathroom tap ; it is amazing how much water can gather by not opening one tap as when I have opened it I can hear water running out of the drainvalve onto the drive .
 
Aug 14, 2014
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Use a Floe drain down kit to completely empty the pipes of any residual water and you will be surprised how much is left in the system after a normal drain down. You can then just leave drain valve closed and not worry about any remaining water causing damage.
 
Nov 16, 2015
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Happy New year all,
I used to do as Mel and Craig did and open the drain valves leaving the sites. Earlier this year I had a water pump fail so had spare parts and made my own water Removal "Thing" and was surprised as to how much water it removed from the system, We "normally use the van all year but on the times it not in use then I am happy to blow out the water now, 10 minutes and no real chance of a water freeze and burst a joint. . Previously only 1 burst joint in 10 years though. . PS. Valve open.
 
Aug 14, 2014
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I assume your 'thing' is just a homemade version of the Floe. Indeed it is surprising how much water is left in there. I certainly feel much happier knowing that there is no water left in the system.
 
Apr 20, 2009
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benshepherd said:
I assume your 'thing' is just a homemade version of the Floe. Indeed it is surprising how much water is left in there. I certainly feel much happier knowing that there is no water left in the system.


Umm dont be to sure!!
Oct 2017 drove from Stratford upon Avon to Devon 160+ miles with drain valve and taps open
Got home and drained down using floe system and yes there was still water in there,
Did each set of taps three times each.
Sept 2018 took van for one night to daughters wedding again taps and drain open both ways, did not use water at all.
Oct 2018 service booked, so set up water etc and primed system ready for engineer in morning.
WATER POURING OUT BACK LOCKER, TRACED IT TO KITCHEN TAP
Yep you guessed it water still in tap, froze which caused the problem.
Dont know actual problem as told Mrs to get engineer to sort next day, but he did say it was due to cold snaps.
 
Mar 14, 2005
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If water is still left in the pipes after the final journey home with the taps open, It very unlikely that it would drain out by its self whilst the caravan is left in storage if the taps and valves are open.

I personally have never had a problem, but I can full accept that others may have difficult pipework.
 
Sep 26, 2018
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This is a perennial issue on boats. We have 60 gallons of water aboard ours, the only way to drain is to pump out through the taps, and there is ALWAYS water left in the system (which includes a calorifier to heat the water from the engine). I always leave the sink taps on to let the residual run back to the tank, on the basis that a little in the tank if it freezes won't create any damage through expansion as water freezes - which is what causes water system damage. With temps having been down to -7/8C last winter there was no damage.

Damage only occurs if water is left in places where the pipework is "full" across the whole pipe.
 
Mar 14, 2005
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Guzzilazz said:
Damage only occurs if water is left in places where the pipework is "full" across the whole pipe.

This is not necessarily correct. It depends on the shape of the containment such as inside some types of valve, If for example the void tapers such that its narrower above the surface of any remaining water, once the top surface has frozen, it will jam in the taper and resists any further upward movement with increasing strength as the thickness of the ice increases, and it will begin to exert more force downwards and sideways.

The inner shape of some non return valves (if lying horizontally) means that lying water at the lowest point will freeze and expand side ways, this can cause the shuttle to move and expose the rubber O ring which being relatively soft and elastic will continue to be displaced from its seated position, and when the ice melts, the O ring can be trapped partly out of position rendering the NRV jammed and leaking. This was a quite common problem for the Carver Cascade 2 water heaters, and why proper draining is so important.
 

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