Boiler valve dump at 3deg (1 Viewer)

[ronidog1]

What strategies do you have for coping with the automatic boiler valve dump at 3degs?

Particularly

Overnight on site with ehu
Overnight on site without ehu
During the day when parked up for a walk etc

My van is a 5.5m panel van conversion

Thanks ronidog

 

[Vanderek]

Have a look at this thread .....I fitted a Truma Frost Control - see content of thread ...

https://www.motorhomefun.co.uk/foru...-all-the-water-when-cold.165909/#post-2620330

 

[Lenny HB]

No problem if you have had the heating on in the van in the evening there will be enough latent heat in the van. I would be very suprisedif your van dropped much below 14° overnight.
If you are worried about it there is an electric heater for the dump valve its about £40.

Having said that there is a Funster with a Knaus who had problems the valve dumping, it was right next to an external locker door away from the boiler.

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[ronidog1]

I would be happy with boiler only dumping and then needing a reset. It just seems daft that the fresh water tank then drains as a consequence. Just spoken to the dealer and he says he gets lots of calls about this issue on continental vehicles

 

[nicholsong]

I would be happy with boiler only dumping and then needing a reset. It just seems daft that the fresh water tank then drains as a consequence. Just spoken to the dealer and he says he gets lots of calls about this issue on continental vehicles

I think that only happens if the pump has power and is trying to replace the water draining from the boiler.

If one thinks that the valve may dump because of the temperature drop, one can simply switch off the pump at night or while away from the MH.

Geoff

 

[TheCaller]

My solution is the same for all three of those scenarios.

Leave the heating on at it's lowest setting - or a bit above its lowest setting if I'm in the van too. I have a Truma Combi, so on the rare occasion that I am on an unmetered EHU, I have the option of using the electric to keep the chill off.

I only have experience of a dump valve on a van where the pump is controlled by tap micro-switches. So if the fresh water tank also empties, it's a syphon effect rather than the pump running. A combination of a dump valve & a pressure sensing pump doesn't sound good, because once the tank was empty, the pump would dry run until either the pump failed or the power ran out.

There are some advantages if the whole tank is drained. While it's a nuisance if the temperature only drops a little below 3degs, if it dropped well below freezing, emptying all the water & preventing damage elsewhere in the system would be a positive outcome.

Why 3deg?

The temperature sensing won't be 100% accurate, so a safety margin is needed.
Water begins to expand below 4degs, so in a closed system, pressure is already building in advance of the larger expansion that will happen once freezing occurs.
The dump valve is unlikely to be at the most exposed part of the pipework. A surprising number of vans have pipes routed underneath the van, so allowance may be made for other sections freezing first.

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[Lenny HB]

I would be happy with boiler only dumping and then needing a reset. It just seems daft that the fresh water tank then drains as a consequence. Just spoken to the dealer and he says he gets lots of calls about this issue on continental vehicles

I think that only happens if the pump has power and is trying to replace the water draining from the boiler.

Pump doesn't need to be running, it happens if the feshwater tank is higher than the valve, mainly on single foor vans where the tank is under the lounge seat.

 

[ronidog1]

Yes the water syphons out the taps have micro switches.

 

[daveandsan]

Never had a problem with ours dumping as long the motorhome is occupied, if you have had the heating or hot water on in the night you should have enough latent heat in the van for it to last a good few hours before it drops to 3 deg.

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[ronidog1]

Never had a problem with ours dumping as long the motorhome is occupied, if you have had the heating or hot water on in the night you should have enough latent heat in the van for it to last a good few hours before it drops to 3 deg.

Thats what I have been thinking. However I perhaps should carry a container with water when wilding or britstopping, just in case.

 

[tonyidle]

I think that only happens if the pump has power and is trying to replace the water draining from the boiler.

If one thinks that the valve may dump because of the temperature drop, one can simply switch off the pump at night or while away from the MH.

Geoff

No - it depends on whether a siphon effect is possible. My Hymer did it.

 

[tonyidle]

What strategies do you have for coping with the automatic boiler valve dump at 3degs?

Particularly

Overnight on site with ehu
Overnight on site without ehu
During the day when parked up for a walk etc

My van is a 5.5m panel van conversion

Thanks ronidog

Simple - keep heating or hot water on. Use mains on EHU, gas when not. In Winter I turn on the heating before leaving home & turn it off when we return.

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[ronidog1]

Simple - keep heating or hot water on. Use mains on EHU, gas when not. In Winter I turn on the heating before leaving home & turn it off when we return.

Sorry if I sound a bit slow, but do you have the gas powered heating on whilst you are driving and parked whilst visiting somewhere?

 

[PhilandMena]

I switch my pump off at night and let nature take it's course. If it dumps it dumps. I just close the valve in the morning and refill the boiler ! job done.

 

[ronidog1]

I switch my pump off at night and let nature take it's course. If it dumps it dumps. I just close the valve in the morning and refill the boiler ! job done.

My issue is that the boiler dumps and then that causes the main fresh tank to dump through syphoning.

If it was only the boiler it would not be an issue

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[PhilandMena]

My issue is that the boiler dumps and then that causes the main fresh tank to dump through syphoning.

If it was only the boiler it would not be an issue

OK ! On my system (autotrail) boiler only fed from water tank via pump so easy to manage.

 

[ronidog1]

Ahhhh the easy Iife - not always possible with the compromises we make when getting a van

 

[deleted-member02]

A clothes peg will stop the valve dropping and emptying the tank.
Obviously only a good idea if you're confident that the boiler won't freeze....

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[Lenny HB]

A clothes peg will stop the valve dropping and emptying the tank.
Obviously only a good idea if you're confident that the boiler won't freeze....

Only on the older electric valves, they are mechanical now and difficult to hold closed.

 

[tonyidle]

Sorry if I sound a bit slow, but do you have the gas powered heating on whilst you are driving and parked whilst visiting somewhere?

Of course - why wouldn't you? Apart from anything else I've never come across a base vehicle heater worthy of the name so when driving in very cold weather l need the extra from the hab heating. As do my dogs.

 

[Feltwell]

The dump valve in my van sits in the cupboard with the boiler - so as long as there's some hot water in the boiler it stays nice & toasty - are they put elsewhere on some vans?

I took my van in for a service recently, and as requested I put some water in the tank and delivered the van with the pump switched off. When I picked it up I didn't notice they'd left the pump switched on - overnight in the cold on my drive the dump valve tripped, which if course now not only emptied the boiler but triggered the pump to empty the water tank until it ran dry, and keep on running continuously.

Luckily I went into the van the following day and noticed this as otherwise this could have been left running for a very long time. The pump seems to be OK.

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[Emmit]

I live in the 'Pointy Bit' about 12mls up the Tamar from Plymuff.

Habitually we wouldn't dream of dumping the water on the approach of winter as freezing is rather unusual around here.
In addition, the 'van is a double skinned Hobby and rarely has temps that get down (at home) to within the range where the dump valve would come into operation. On top of that, it has the Clothes Peg Accessory so there's no chance of it occurring.

However, this week, the weather has been negatively, 'Up Country'. We've even had frost and the white stuff.
So, in order to prevent any chance of having a stuffed boiler, I've taken to going out into the cold and putting on the boiler on both water and heating at about 10.00pm for half an hour. On returning to the 'van, the temp (air) inside is a comfy 17-18 degs and the water is at about 60degs.
On returning back to the 'van AM I've discovered that whilst the water coming out of the 'Hot' tap isn't even warm, there is sufficient lack of cold to make freezing impossible.
An eight letter Yorkshire word comes to mind, "That'll do".

I appreciate that I'm on 'The Edge' but as said, it's such a rare occurrence that the above is a temporary measure.

 

[Mike800966]

WE have the famous Truma Dustbin system to which I retro- fitted the electric strap on heater, if its that cold and we are on hookup, I leave that on. If no EHU then leave Gas on low. The boiler is under the bed so its keeps us nice and warm as well. The other thing is that I have extended the reset mushroom headed thing with some garden wire so when it does trip out ( and ours will dump the entire cold tank as well) then by reaching in I can pull up the wire and reset the dump valve. Bear in mind that this doesn't seem to stop it dumping if it wants to but does stop it when it has started to dump.

That reminds me of the first time we tried to fill, a freezing cold night down at Vanbits site and we couldnt get water to stay in the cold tank as it was p*****g out the blasted dump valve! One learns these things
Mike& Ann

 

[wigster]

If i hear these singing i know my valves going to open so to speak .


Sorry

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