Hot water tank

[Plug]

Now that were well into the caravan season we go away most weekend rallying with our DA
We have started to leave our hot water tank full and not drain it down everytime were away i was just wondering if other caravaners do the same or drain it down everytime you leave site i cant see it doing any harm to the tank but we always drain down in the winter months incase of frost

 

[Hutch]

We drain our water heater tank, every time we leave site, to save the weight on the Caravan, ok it is only 10 kg but everything adds up. If you have spare user Payload and (the dreaded Nose weight) it's up to you.

 

[Dustydog]

Oh dear one or two little yellow taps. Drain down before every journey. The weight of water in the tank will affect your calculated nose load

 

[Mickyjb]

If you're happy with your nose-weight and payload then leave it - I did with the previous 'van and intend to with the current one. Still learning at present as we're only 5 trips into the season and the Fiamma only went onto the new van on the last outing. So far the nose-weight is as I want it (~100kg) and the 'van tows very 'comfortably' although the variables need thinking about. I'm now using Calor 'heavies' instead of the previous Calor 'lights' but (due to 6 months-worth of generosity on the part of ERNIE) I now have a 'Lithium' battery (14kg vs 28kg) so, check what you're towing. We - like you - are now into peak rally/meet/THS season. So, measure, judge and enjoy - whatever that means for you .

 

[ProfJohnL]

It depends on the make and model of water heater you have. In some models the inertia of the mass of water in the tank sloshing around when you tow can put undue strain on tank joints and seals and can damage the heater.

For caravans especially where pay loads are usually minimal, carrying the 10Kg or so of water uses up payload which you might need for other things.

Depending on where the heater is located, the 10Kg or water will affect the nose load you caravan applies to the car.

But in addition all motoring organisation will tell you that carrying unnecessary weight in a vehicle or trailer uses more fuel to complete the journey.

If you not sure, the safest way is to drain before each journey.

 

[Martin_E]

Although weight can be an issue for me it’s Legionnaires' I would be more worried about when leaving water in the van.

 

[Sam Vimes]

Although weight can be an issue for me it’s Legionnaires' I would be more worried about when leaving water in the van.

The thermostat on the heater is probably set to somewhere around 70degC and this will kill off any Legionlla bacteria.

I drain mine to save weight. Having said that on my last trip home I forgot but the nose weight, which I always check was still ok.

 

[JTQ]

We are fortunate in that by design the Alde 3010 is over the axle and we have a generous weight payload so there are no issues with noseweight or over weight, therefore on those it matters not if we drain the system.

We predominately use grass pitches, CLs, rallies etc so can't on pitch drain our hot water as that will kill the grass.
Consequently, more often than not I do not, cannot acting responsibly drain down prior to leaving a site.

As Alde recommend for the 3010 in the context of keeping a small air cushion in the "crown", I do routinely drain as and when I think about it, this I can do at home as the carport's floor is a mix of concrete paving with gravel filled divisions.

The issue raised re Legionella bacteria risk is address in the design of Alde systems, well certainly our 3010 and I suspect that feature was not dropped in the later design. A burst of boosting the hot water temperature, which lifts from the lower level of 50C to circa 70C fully addresses that, as can its use with space heating.
Even draining the Alde boiler in our case and I suspect most others will still leave trapped slugs of water within pipes exposed to develop biological infestations of one type or another during periods out of use, I also suspect the water trapped in the boiler, void of any light, would be one of the lower risk areas in that regard.

 

[Beachball]

We use to drain our water heater down every journey the water in the tank will affect your nose weight

 

[Buckman]

The thermostat on the heater is probably set to somewhere around 70degC and this will kill off any Legionlla bacteria.

I drain mine to save weight. Having said that on my last trip home I forgot but the nose weight, which I always check was still ok.

I think that with many normal or standard systems, I doubt if the temperature goes above 65C. More than likely to comply with health and safety and to prevent a child from being scalded? The ALDE does have a boost which increases the temperature to 65C, but they do not give a figure on how much.

 

[Hutch]

I think that with many normal or standard systems, I doubt if the temperature goes above 65C. More than likely to comply with health and safety and to prevent a child from being scalded? The ALDE does have a boost which increases the temperature to 65C, but they do not give a figure on how much.

On my Coachman with the Truma Combi heater, the Blurb states when the water heater is warming up the temperature will raise to 70ç and then settle back to 60ç or 40ç which ever you have it set to.

 

[JTQ]

Our Alde 3010 "Operation Manual" states a "set temperature" of 80 C for the glycol solution, and in the Specification section a maximum of 85C.
Whilst the "set" temperature is the glycol, this can result in the water system reaching that temperature.

Scalding can occur at way lower temperatures, to an extent it depends on the exposure time though that's always in seconds or fractions of seconds.
Over 44 C is deemed dangerous for showing, and more generally we are in scalding danger within a few seconds from 55C upwards.

Unfortunately, with our caravans there is no statutory dictate to regulate the water temperature at taps etc, as in the UK there can be elsewhere, here its user be aware.

 

[otherclive]

The topic of LD crops up periodically but I’ve never seen evidence that anyone has caught it from caravan water systems. This link was extensively discussed a while back.

LD thread

Evan Elsan marketed their vehicle screen wash as an anti LD precaution. Presumably some bought it solely on that account. 😂

 

[Buckman]

Our Alde 3010 "Operation Manual" states a "set temperature" of 80 C for the glycol solution, and in the Specification section a maximum of 85C.
Whilst the "set" temperature is the glycol, this can result in the water system reaching that temperature.

Scalding can occur at way lower temperatures, to an extent it depends on the exposure time though that's always in seconds or fractions of seconds.
Over 44 C is deemed dangerous for showing, and more generally we are in scalding danger within a few seconds from 55C upwards.

Unfortunately, with our caravans there is no statutory dictate to regulate the water temperature at taps etc, as in the UK there can be elsewhere, here its user be aware.

The Glycol solution may be set to 80C, but the water temperature is regulated to 55C according to the manual for the 3020. To check go into settings menu and then "Service". It will show you the details.

 

[JTQ]

Evan Elsan marketed their vehicle screen wash as an anti LD precaution. Presumably some bought it solely on that account. 😂

Interesting, I can see there a better case with under bonnet temps so frequently stood above the 20C threshold, plus in use the tendency to create a spray atmosphere that reaches internally to be breathed in.

Again, as with our caravans I don't hear of any genuine cases of "real"LD incidents, the caravan one simply because it runs hot enough to cook it without us getting concerned about it.

 

[Martin_E]

The thermostat on the heater is probably set to somewhere around 70degC and this will kill off any Legionlla bacteria.

I drain mine to save weight. Having said that on my last trip home I forgot but the nose weight, which I always check was still ok.

The thermostat probably will, but that doesn’t stop it in the dormant water sitting in the pipes

 

[JTQ]

The Glycol solution may be set to 80C, but the water temperature is regulated to 55C according to the manual forth 3020. To check go into settings menu and then "Service". It will show you the details.

I have not the 3020 or its manual, however if the word "regulated" is used then that has to be by oversight of the reality in that the water can reflect whatever the glycol temperature reaches.
In non space heating mode then yes the water stat could override things and ensure the temperature is "regulated"; in space heating mode that control become sidestepped.
The glycol fluid and water are only physically separated by a stainless steel sheet shell, zero barrier for heat transfer.

 

[RogerL]

The Glycol solution may be set to 80C, but the water temperature is regulated to 55C according to the manual forth 3020. To check go into settings menu and then "Service". It will show you the details.

The design principle of the Alde means that the hot water can exceed it's set temperature simply by conduction from the circulating glycol, if the system is calling for room heat.

The 55 degree set temperature simply triggers heating of the water if it's under 55 - nothing stops it going above.

 

[ProfJohnL]

According to the Health and safety Executive
here
legionella bacteria can be found in many natural water sources. below 20C they will be dormant and above 60C they die.

Most domestic water has been filtered and treated enough to reduce the risk of LD infection becoming a danger, but the problem usually arises in the way the water is stored or used within buildings, where tanks and pipes can be exposed to temperature's that can activate dormant bacterium and facilitate its reproduction.

There can be little doubt that water systems used in touring caravans can also experience ranges of temperature that would be suitable for the LD and other undesirable growths to multiply, especially whilst the caravan is in storage.

It is therefore a sensible precaution to thoroughly clean your water system after a period of non use, using sterilising fluids or other proprietary cleaners. Don't forget to also clean your shower head, and taps.

When in daily use, water systems will normally h ave sufficient through put to to prevent an unsafe build up of bacterium, also helped by the hot water reaching 60C in the tank.

If LD had been a big problem in touring caravans I think we would have seen reports of it, and a big push from the clubs and magazines about how to manage it, but I can't recall seeing any reports - suggesting it isn't major issue, however that doesn't mean we shouldn't take reasonable precautions and keep a watchful eye out for it.

 

[otherclive]

Given the "gunge" that seems to build up in caravan systems I always sterized mine at the beginning of the season, and at the end. I always drained the system when leaving a site too. On arriving on site after filling the system the water heater would be switched on and hot water run through to the shower head. Whilst the HSE papers can be useful info they are mainly geared to non domestic premises for protection oof residents, staff and maintainers. Although landlords also have a duty of care. But I've yet to hear of social housing providers doing what the HSE advise, or even asking their tenants to so do. What do you do at home after arriving back from a two week trip away?

 

[Martin_E]

According to the Health and safety Executive
here
legionella bacteria can be found in many natural water sources. below 20C they will be dormant and above 60C they die.

Most domestic water has been filtered and treated enough to reduce the risk of LD infection becoming a danger, but the problem usually arises in the way the water is stored or used within buildings, where tanks and pipes can be exposed to temperature's that can activate dormant bacterium and facilitate its reproduction.

There can be little doubt that water systems used in touring caravans can also experience ranges of temperature that would be suitable for the LD and other undesirable growths to multiply, especially whilst the caravan is in storage.

It is therefore a sensible precaution to thoroughly clean your water system after a period of non use, using sterilising fluids or other proprietary cleaners. Don't forget to also clean your shower head, and taps.

When in daily use, water systems will normally h ave sufficient through put to to prevent an unsafe build up of bacterium, also helped by the hot water reaching 60C in the tank.

If LD had been a big problem in touring caravans I think we would have seen reports of it, and a big push from the clubs and magazines about how to manage it, but I can't recall seeing any reports - suggesting it isn't major issue, however that doesn't mean we shouldn't take reasonable precautions and keep a watchful eye out for it.

👍good post

 

[Sam Vimes]

This is not my area of expertise - just looked into it when we installed a hot water solar panel system as this has the potential of heating the water to usuable levels but not enough to kill off the bacteria.

The bacteria comes from fresh water supplies but supposedly the introduction of chlorine into the water suppy will reduce the risk.

Legionella's Desease is basicaly a respitory desease caused by the inhalation of the bactiera. There seems to be little evidence that drinking water can cause the desease although it's acknowledged that there is the potential to inhale some water when drinking.

Because its primarily a respitory desease, shower heads are particularly vunerable areas.

As Prof states the bacteria lie dormant below 20degC and are killed off at levels about 60degC (although I've seen mention of 55degC). In between these extremes the bacteria can multiply.

The temperature level set on the tank should be above the 60degC level to ensure the bacteria is killed off and the recommendation is that hot water should arrive at the taps within 1 minute. Presumably this is to kill or reduce bacteria in the pipework. In many houses - including mine 1 minute is not acheivable in some places. In our caravan the hot water arrives well within the 1 minute limit.

Potential problems could arise when the hot water is being diluted with incoming colder water, in which case the tank and hot supply pipes will be below the 'kill off' threshold.

Cold water supply could also be a potential problem, particularly for us caravaners. Some store cold water in Aqua Rolls which may well sit in the sun. Cold water temperature is recommend to be below 20degC but the sun could well heat the Aqua Roll to above this temperature which brings it into the region where the bacteria can begin to multiply.

For my part I sanitise the Aqua Roll after trips with a dilution of Milton. Occassionally I will run a dilute solution of this through the pipe work, both supply and waste.

In our house the supply water is from the water company but by the time it gets to us - which is almost the end of the run - there is little evidence of chlorine. Further up stream the Chlorine can be very strong. Regardless we have a whole house water filter which does other things than just reduce the taste of chlorine. Because of this I periodically sanitise the house pipe work with a dilution of Milton. Usually this is done when we change the house filter.

Actions we can take may reduce the risk but I don't believe reduce it to zero.

 

[Raywood]

Not a scientific approach but due to handling and being involved with insurance claims. Other than commercial premises involving storage tanks I have never seen any cases. The problem has largely been in hotels where water is normally stored in tanks on the roof. These have needed to be cleaned out at regular intervals and if it has not been done the risk is there. I have also had one case of water blowing out from an open water storage tank which was sited at the very edge of a factory complex in stormy weather.
Given the lack of any reports from caravans or statics I do think the risk s very low, but must be there, so I would not criticise anyone taking the precautions mentioned.

 

[Dustydog]

Same as Ray. The only places I’ve seen over the years with potential LD ate large cooling tanks on high rise buildings and factories including air con. The common denominator has always been the water droplets / mist within which the LD grows, not the actual water itself. The disease is passed on through the air , similar to pneumonia. I have never heard of anyone catching LD via water in a caravan.