Frost control/Drain Valve

We are booked on a site this week . Of course the washrooms etc are not currently available.

I note that the overnight temperature is due to fall to zero.

If the facilities had been available I would have left the water system winterised but now I propose to take water in the tank and have hot water.

It seems likely then that the drain valve might automatically  empty the the heater in the night.

The Nuevo manual suggests the temperature at the frost control needs to be back to 7c before I can refill the water heater best achieved by turning on the room heater.

1. Assuming the temperature is still low when we get up, how quickly would the 7c be reached with the room heater activated?

2. What sort of  temperature could the room heater be left on overnight, to hopefully avoid the water dump?

3 My wife wonders about leaving a hot water bottle in the vicinity of the valve?

Thanks

id have thought the temp would need to get well below zero and for a sustained period to trigger the auto dump....although they do seem to vary in 'sensitivity' ive never had mine trigger.
however, if it does go and youre struggling to reset it, a hot water bottle, or even a hairdrier are both tips ive seen.
normally, by having the heating on in the evening, and perhaps very low overnight, you shouldnt get any trouble.
good luck.

Mine tripped out this week when I tried to fill with water first thing in the morning when planning our beach walk. It kept tripping out, but after resetting it loads of times it eventually stayed in. Was a frosty night, been ok since, just filled tank as we are off in the morning for 5 nights, so will see if ok tomorrow.

I have read on here to ditch the auto valve and just fit a manual one in it's place, just beware of cold spells.
 Good idea about the hot water bottle, we always take our's even when we could go to France, you never know when you might get taken poorly and need one.
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Richard

Richard, one of the issues at this time of year is the low temperature of the water from your household supply.....might be colder than the ambient temperature..
as its the blue button that pops out, one other 'tip' is to loop a cable tie around the valve ensuring it holds the button in...

bolero boy wrote:Richard, one of the issues at this time of year is the low temperature of the water from your household supply.....might be colder than the ambient temperature..
as its the blue button that pops out, one other 'tip' is to loop a cable tie around the valve ensuring it holds the button in...

Come to think of it, the hose was a bit frozen at first. Cable tie a good idea, now why didn't I think of that, I could say I am not as clever as you  let's hope others find it useful also.
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Richard

not clever, ive just read a lot of MH forums where tips and ideas are plentiful...

Unless you have antifreeze in your blood, you will want to have your heating on overnight.  We find 14 degrees is a comfortable overnight temperature.  There will then be no risk of your frost valve triggering especially as its close to the Truma Combi and there is a heating duct in the locker.  If it's very cold by day and you leave the van, I would leave the heating on at about 14 degrees and switch your water pump off just in case there is an EHU outage whilst you are away.

Never had the heating on at night before, even in snowy Dentdale. Val sleeps nearest the kitchen so she normally puts the heating on, if needed, while the kettle is boiling ,first thing in the morning.

Thanks. We'll take on board your suggestions. Just a couple of nights at Pooley Bridge.

They are forecasting zero overnight at Pooley Bridge.  If you really don't want to leave the heating on switch the water pump off.  If not and the frost valve triggers which it should do at 3 degrees, the water system will depressurise making the pump come on emptying your fresh water tank and potentially burning out your Whale pump if it's left running.  You will be so far under the duvet you might not hear it!

We will do what you suggest and have the heating set at 14 overnight. Will have the winter duvet with us!
Thanks

Sorry one last (stupid) question

Whe I leave the heating on overnight, does the pump need to be left on?

no turn off the pump for safety
with the heat from the heater keeping the water hot should keep the temperature ok to stop the drain valve operating
I have never had mine drain down with the truma heater on when away in - temperatures

jetty wrote:Sorry one last (stupid) question

Whe I leave the heating on overnight, does the pump need to be left on?

To be serious about it, if the pump goes off whilst you are in the van you will hear it even if you are under your duvet.  When you are away from your van though, you should switch the pump off.  As Glyne says, if you leave a little bit of heat on, the Truma frost valve should not trip.  If you are leaving home early tomorrow morning you may find that the frost valve has tripped overnight and wont reset until the locker space has got to 7 degrees.  This isn't a problem because you can have the heating on whilst you are driving or put it on when you get to the site which will raise the temperature allowing the valve to be reset and the water system to be primed.

My heater does not operate when driving because the 12v habitation supply is cut.
No habitation electrics equals no heating.
Keith

KMRTOPAZ wrote:My heater does not operate when driving because the 12v habitation supply is cut.
No habitation electrics equals no heating.
Keith

It may only be the more recent models that can have the Truma Combi gas heating on with the engine running.  I've experimented with it on the drive and it works.  Personally in this Country I would only use the vehicle cab heater whilst driving and not put the Truma Combi on until a I reach the destination.  I have found it doesn't take it long to warm things up sufficiently to reset the Truma frost valve and then prime the water system.

If driving in freezing temps remember the tanks and pipes are exposed in the freezing airstream under the van and speed provides it's own windchill factor. If you travel with water in your tanks you could end up with very large blocks of ice inside them.

That was one good thing about our Adria Coral Compact, back in 2008 to 2010, it had it's 120 litre fresh tank under the rear seats, so inside in the relative warmth of the van. The frost valve was right by the Combi and toasty and it had narrow warm air ducting all round the outside edge of the fixed rear double bed mattress. That stopped any drafts and gave a nice background warmth.

steamdrivenandy wrote:If driving in freezing temps remember the tanks and pipes are exposed in the freezing airstream under the van and speed provides it's own windchill factor. If you travel with water in your tanks you could end up with very large blocks of ice inside them.

I agree.  Although our van has external tank heaters I would travel with empty tanks if there was any chance of freezing.  The heaters must put quite a load on the electrics.  To me they are more useful when on an EHU pitch in very cold conditions.

Jetty 
If you are on ehu you have got the tank blankets and element in the tank you can use

I just came across this piece (edited a bit by me) which might help newbies understand a bit more about the differences between 'insulation' and 'winterisation'.

we often see motorhome adverts from many converters with large splash banners telling us that this vehicle has 'Grade three insulation'.

..yet we also see how folk in such vehicles still have to manage their water systems dumping water at temperatures well above freezing and also having to resort to 'interesting solutions' (hot water bottle, hairdrier, cable tie....all common 'tips') in order to re-prime a cold system...

the headline advertising quoting 'Grade three insulation' is a great eye catcher as it suggests perhaps more than it actually is, and this leads to high expectation in customers....but also confusion as to why certain measures are often needed despite their van having the highest 'insulation rating'...

so, what does it really mean?

the first thing to understand is that this is not a reference to “winterisation” or a “winterised unit”. That is a different thing altogether.

A motorhome or caravan that is constructed with insulation grade three should be able to maintain an interior temperature of +20 degrees centigrade internally, with the heating system on, when the outside temperature is -15 degrees centigrade. It is as simple as that.

Of course, if you throw enough energy at something, then any temperature inside should be achievable. For example a glass greenhouse could probably be maintained at twenty degrees centigrade when it is -15 outside. However, tremendous amounts of heat energy is likely to be needed.

On the other hand, a motorhome that is fully winterised generally has all plumbing, (ie fresh water tank, waste water tank, drain pipes and fresh water pipes) certainly inboard (as mentioned by Andy) but ideally located in a twin floor. The space between the twin floor usually has a heat source too.

It is possible that you could buy a motorhome or caravan with insulation grade three only to find that the fresh water tank is underslung and therefore possibly at risk of freezing in the wintertime. So, in reality, the motorhome or caravan would be warm and snug internally, but the water tank could be frozen solid. 

The point here being that the insulation grade of the unit is not the same as being “winterised” and often this is where the confusion arises and that customers are not fully briefed by sales staff as to the differences and to therefore manage their (realistic) level of expectation.

I agree with you bolero boy.  Grade 3 insulation is a con.  No one can claim for example that an AS cab has Grade 3 insulation.  It would be more useful if they came up with a metric for the energy needed to maintain the interior of a caravan, motorhome or campervan at 20 degrees when its minus 15 outside.  This will encourage more efficient designs and help save the Planet.

Indeed our warwick pvc has no insulation at all in places where you can see and feel the outer metal skin freezing in winter and hot in summer.
Putting it right where I can.

the Grade III test is done in a cold chamber and the heating is whacked up high on gas...either 4kw or 6kw depending on unit.
no one ever says there isnt a cat in hells change of this also being acheived using electric (1.8kw), hence many customers being disappointed at the lack of winter warmth when just using EHU.
the simplest way of moving along the 'winterisation' route is to move the fresh tank inboard...this is pretty much de rigeur on Continental vans, even on PVCs...but we (UK) dont want to give up that storage to a water tank. perhaps thats why the Continentals work so hard to create other storage areas?
its often the pipe from the fresh tank (outside) to the other plumbing (inside) which is susceptible to the cold as its full of water when the system is primed.
at least with a waste tank outside it can be left open and drained into a bucket to avoid issues....not so easy with a fresh tank.
@Caraman...cabs can be the coldest, least isulated part of the van but, even in front lounge layouts, converters often place the Combi at the opposite end of the van, how can that possibly work as well as customers would like? if the heater can be placed centrally, this is fine for both front and rear lounge units, with equal pipework lengths...how tricky was that to work out?

Another thing is that many folk seem to assume that if something is 'insulated' it will never freeze. That just isn't and never has been the case. The effectiveness of insulation depends on its ability to block the progress of heat or cold transfer. A good conductor of heat that's not very thick will let cold or heat through in no time. Conversely a poor conductor that's very thick will take a long time to let hot or cold through. The point here is that given long enough and a big enough temperature difference and even the best insulation will eventually let cold through to freeze what's inside it, all any insulation does is slow that process down.

Also you surely have to be a bit vacant if you expect stuff that is exposed to freezing temperatures outside and not inside a heated envelope to not freeze up.

"Also you surely have to be a bit vacant if you expect stuff that is exposed to freezing temperatures outside and not inside a heated envelope to not freeze up."


Andy, not sure about 'vacant'...new customers, who know little about the vans they are buying, are (unless they've been scouring forums for a good while) pretty reliant on the salesman/technician who does the handover and when it comes to heating, hes going to be singing the praises of the unit, its performance and its 'grade 3 rating'...
similarly with the water system, the focus will be on how you get water in and use it, not how you run the combi empty in severe winter conditions.
we all have to learn and often, with MH, the hard way....and we all get much wiser after the event..
imthink this is why highlighting some of the confusion that customers come across is always a good thing.
we all know that vans just cant do everything the salesman tells us, we get to understand the areas where hes been a bit 'enthusiastic' sometime later, in the middle of a cold field...

During these last, cold winter months I've kept my 'van plugged in to EHU and set the temperature to its minimum 5 degrees heating setting, so as not to drain the water system and all has been fine (except for the 'leccy bill).
I've not had it plugged in since giving the 'van a run last week and we've had a few overnight frosts but the valve hasn't tripped.

Saturday night was cold, but no frosts and I checked the 'van at 7 o'clock when I got up and all still OK.
Went out a 9 and the valve had emptied the boiler, so the temperature must have been still dropping enough to go below 3 degrees inside the 'van.

Rather than leave the heating on overnight, is there a problem with just leaving the hot water system switched on (even on economy) to stop the boiler emptying?