Elddis Avante 868 - Cold at the back! :(

[Bracechenk]

Hey guys - We bought a new Avante 868 this year and appear to be one of the lucky ones as we only had to wait 5 months to get it. We're a family of 4 with a 3 and a 7 year old so the bunk bed layout and bedroom contained at the back is perfect for us. There were some very early snag list sort of things that needed doing but our dealer sorted them immediately without fuss (small stuff, clips missing, alarm not wired in etc).

However, one issue is that the back bedroom is significantly colder than the living area and it's a bit of a problem. The temperature difference is such that in order to make the bedroom warm and comfy for when the kids go to bed, the front of the van is boiling! Has anyone else experienced a similar issue with this van (or 866/860)??

I did raise this with our initial snag list and the dealer found no issue and said that the heat coming from the vent is within spec. The van has 3 heater outlets, 1 in the living room, 1 in the bathroom (with a butterfly valve) and 1 in the bedroom. I've checked for kinks, leaks or any other issues and can't see any but the air volume being pumped out of the bedroom vent is noticeably lower than the front vent.

My suspicion is that this is a design flaw rather than a fault but it would be great to hear from others if you have similar experience or if this isn't an issue. The heater splits into 2 heat ducts, 1 travels only a foot into the front vent, the other travels the length of the van and also splits to service the bathroom vent so I think it's just the result of this design. I do of course close the bathroom butterfly valve but I guess this would still leak air. Bit silly if this is how it's supposed to be as it's almost unmanageable in the colder months....might need to whack the heating up high and open roof vents in the front of the van to balance out the heat

 

[otherclive]

If adjusting the flow between front and back by adjusting vent valves has not improved it, then there is normally a two way flow adjuster on the Truma unit which can be moved to split the air between the two outlet ducts to give more flow in the direction required. The Owners Manual should advise.

 

[ProfJohnL]

High Bracechenk,

Welcome to the forum

Whilst you don't tell us what make and model of heater have, I deduce your reference to the butterfly valve you have a blown air system. The make isn't all that important as the blown air systems all have the same basic method of operation.

Blown air systems always have more difficulty working in longer caravans, for two reasons, the first is the longer the pipes the more resistance to flow increases with the length of the duct, and the longer the duct more heat can be lost before it reaches the furthest outlet.

You need to experiment to balance the system. If you partially close the outlet butterflies closer to the heater, the more air flow and heat will reach the more distant outlets. Depending on the model of fan system some do have a diverter valve that can allow you to proportion the amount of air passing into each duct. Details should be in heater/fan manual.

In some caravans a section of the hot air duct has to pass the doorway, so the caravan manufacture routes the duct under the caravan. These sections really should be insulated to prevent heat loss, but cost cutting manufacturers may not have done this.

Just out of interest, I was employed by a major appliance manufacturer, and some of our products were used in caravans, and as part of our development process we used to test whole caravans in an environmental chamber. We were asked by one manufacturer if we could test some heating systems. In one case a caravan manufacturer had a very strange arrangement, and with very little work we found we could create a continuous loop of hot air ducting with both ends attached to the fan outlet. This massively improved the heat distribution at the furthest outlet becasue it could receive air from both ducts.

 

[Bracechenk]

If adjusting the flow between front and back by adjusting vent valves has not improved it, then there is normally a two way flow adjuster on the Truma unit which can be moved to split the air between the two outlet ducts to give more flow in the direction required. The Owners Manual should advise.

Ah - I didn't know this but I think it's an Alde wet system rather than Truma. Still, worth me looking into the manual to see if there's any guidance there although I would have hoped that the dealer would have adjusted it if there was.

 

[Bracechenk]

High Bracechenk,

Welcome to the forum

Whilst you don't tell us what make and model of heater have, I deduce your reference to the butterfly valve you have a blown air system. The make isn't all that important as the blown air systems all have the same basic method of operation.

Blown air systems always have more difficulty working in longer caravans, for two reasons, the first is the longer the pipes the more resistance to flow increases with the length of the duct, and the longer the duct more heat can be lost before it reaches the furthest outlet.

You need to experiment to balance the system. If you partially close the outlet butterflies closer to the heater, the more air flow and heat will reach the more distant outlets. Depending on the model of fan system some do have a diverter valve that can allow you to proportion the amount of air passing into each duct. Details should be in heater/fan manual.

In some caravans a section of the hot air duct has to pass the doorway, so the caravan manufacture routes the duct under the caravan. These sections really should be insulated to prevent heat loss, but cost cutting manufacturers may not have done this.

Just out of interest, I was employed by a major appliance manufacturer, and some of our products were used in caravans, and as part of our development process we used to test whole caravans in an environmental chamber. We were asked by one manufacturer if we could test some heating systems. In one case a caravan manufacturer had a very strange arrangement, and with very little work we found we could create a continuous loop of hot air ducting with both ends attached to the fan outlet. This massively improved the heat distribution at the furthest outlet becasue it could receive air from both ducts.

Thanks ProfJohn....another nod to checking the manual and seeing what options around diversion there is! Appreciate the response and thanks for the welcome

 

[otherclive]

If it is Truma brown air try contacting Gary at ARC systems he is always willing to offer technical advice on these systems. In another Forum he sorted out a system with similar balance problems to yours.
http://www. arcsystems. biz

 

[GaryB]

We have had the same issue which hasn’t been helped by the ducting being routed underneath the caravan in the central area. I have insulated the run underneath which has helped along with careful balancing/fiddling of the butterfly vents as others have said.

 

[Jcloughie]

The spec for your van shows this:

NEW CompleteHeat Whale 4.3KW Dual-fuel space-saving heating – fast, powerful and efficient, runs on gas and/or electric with quiet night-time setting – and ducted heating throughout including bathrooms

Whale Expanse dual-fuel underslung 8L water heater

If there is not a diverter as OC suggests, I would suggest investigating having a butterfly valve fitted onto the living area ducting. This would then divert heat to the rear. I don't think there should be a butterfly on all outlets, as this would restrict the heater.

As it is a new van, best to do such things in consultation with the dealer.

But only £6:95

CAS 9805 Whale 65mm Directional Vent

www.caravanparts.co.uk

John

 

[Hutch]

Get a big dog, our Labradoodle would sleep over the front heating vents and the toilet and bedroom would be lovely and toasty.
I hope you find a fix for your heating problems to keep the little ones warm.

 

[ProfJohnL]

Even with the Whale system, restricting the butterflies near the heater will reduce the heating effect in their area and divert more of the unused heat further along the ducting to the rear.

 

[Jcloughie]

Even with the Whale system, restricting the butterflies near the heater will reduce the heating effect in their area and divert more of the unused heat further along the ducting to the rear.

If I understand the OP correctly, the heat outlet in the living area has no butterfly, Also, it is very close to the heater. Hence my suggestion to fit a butterfly valve so he can do as you suggest.

John

 

[ProfJohnL]

If I understand the OP correctly, the heat outlet in the living area has no butterfly, Also, it is very close to the heater. Hence my suggestion to fit a butterfly valve so he can do as you suggest.

John

Thankyou. Some models do require the first outlet to be kept fully open.

 

[Bracechenk]

*** UPDATE - For anyone else reading this with a similar issue ***

On further inspection, as already pointed out, the system I have is the Whale 4.3KW blown air system....my mistake sorry. Regarding the butterfly valves, the manual states:-

"Ensure that a minimum of one of the hot air outlet vents is permanently open on each duct branch. This hot air vent must be the furthest distance from the Space Heater".....

There are 2 branches from the heater....the living room vent (permanently open) and the other branch serves the bathroom (butterfly valve) and then continues to the back bedroom (permanently open) so this is correct and means I cannot fit butterfly valves on either of those vents.

Also, I've read the whole manual and there's no mention or any kind of adjustment to the airflow between those 2 branches so it's something that I'll have to live with annoyingly. I'll probably resort to managing the thermal loss in the spaces themselves by ensuring that all blinds, doors and windows are closed at the back whilst I run the heater for a bit before bedtime. Nothing worse than cold bedding especially for my 3 year old who likes to complain even if I give her the wrong coloured socks! .

Thanks for all of your suggestions!
Bracey

 

[Buckman]

In our Lunar Delta we had a similar issue and the result was mould under the bed at the rear wall.

We did as OC has suggested and also wrapped the duct pipes with a type of insulated foil used for camping in cold weather. There was a significant improvement.

Close the front ones so only the bedroom vent is open. Heat will still come up from the ducting pipes where they are on the topside of the floor.

 

[Bracechenk]

In our Lunar Delta we had a similar issue and the result was mould under the bed at the rear wall.

We did as OC has suggested and also wrapped the duct pipes with a type of insulated foil used for camping in cold weather. There was a significant improvement.

Close the front ones so only the bedroom vent is open. Heat will still come up from the ducting pipes where they are on the topside of the floor.

Thanks Buckman but I cannot close the front vents as they don't have a butterfly valve and the Whale unit manual states that they must remain open. However, the foil wrapping on the ducting is a good idea so I'll look into that

 

[Jcloughie]

Get a large dog to lie up against the vent.

I completely agree with the OP’s first assertion, re. very poor design.


John

 

[Raywood]

I agree with those who say the vents need adjusting. We have a ear toilet and find that can be cold with blown air. We normally open all the vents at the front until the front is warm enough for us and hen partially close them and fully open the one in the toilet which then gets more of the heat. Assuming the front vent can be adjusted then once you et the settings right you should be able to get the balance right. The caravan does seem short on vents though, as we have five but it is a different make.

 

[ProfJohnL]

I agree with those who say the vents need adjusting. We have a ear toilet and find that can be cold with blown air. We normally open all the vents at the front until the front is warm enough for us and hen partially close them and fully open the one in the toilet which then gets more of the heat. Assuming the front vent can be adjusted then once you et the settings right you should be able to get the balance right. The caravan does seem short on vents though, as we have five but it is a different make.

In #13 the OP tells us the living room branch only has one outlet, and according to the heater manufacturers instructions, this must not be restricted, so unfortunately many of the suggestions we have made cannot be adopted. From his descriptions he only has three outlets!

Unfortunately this demonstrates how little attention the caravan designers give to heating appliance manufacturers instructions and a lack of understanding they have of heating dynamics.

 

[Milkfloat]

Reportedly the pipe in the rear bedroom of my blown air Adria has small holes in them where they pass along the sides of the van. Other people have reported that making these small holes bigger has increased the heat to the rear of the van. I have a project to use https://www.toolstation.com/ybs-thermawrap-spiral-pipe-wrap/p67097 to wrap the pipe that goes underneath the caravan with aluminium tape on top. I will be doing this when we finally get a dry day and if that does not help, will look into enlarging the holes along the heating pipe itself in the rear bedroom.

 

[Dustydog]

See pages 12-20

Whale | Global Supplier of Pumps, Heating Systems and Plumbing

Whale is a global supplier of high quality low voltage pump, plumbing and heating systems designed for mobile applications and challenging environments

www.whalepumps.com

Nothing like the design of the Truma Ultraheat types which we are all probably used to.
IMO there is a design defect with the Whale but I am not an expert! Truma where the hot air leaves the heat exchanger has a bespoke divider so you can set the air flow bias as desired.
As far as I can see the Whale doesn’t have this facility. Blocking the front vents could cause overheating and possible fire within the boiler unit?? Possibly??

Which leads me to ask is the Alde wet system being phased out🤔🤔

 

[ProfJohnL]

See pages 12-20

Whale | Global Supplier of Pumps, Heating Systems and Plumbing

Whale is a global supplier of high quality low voltage pump, plumbing and heating systems designed for mobile applications and challenging environments

www.whalepumps.com

Nothing like the design of the Truma Ultraheat types which we are all probably used to.
IMO there is a design defect with the Whale but I am not an expert! Truma where the hot air leaves the heat exchanger has a bespoke divider so you can set the air flow bias as desired.
As far as I can see the Whale doesn’t have this facility. Blocking the front vents could cause overheating and possible fire within the boiler unit?? Possibly??

Which leads me to ask is the Alde wet system being phased out🤔🤔

All gas fired heating products legally sold in the UK and the EU must by law be proven to comply with all relevant construction and use regulations, before they can be issued with a UK CA mark or EU CE mark which is the prerequisite for being lawfully offered for sale.

I know how involved much of that regulatory requirement is, and how pernickety the approved test houses are when it comes to compliance - even down to size and form of text and images on the required labeling.

In relation to blown hot air systems, there are statutory limits for the temperatures of certain parts of appliance, and very tight requirements for the either the continued safe operation or cessation of operation under some prescribed stress conditions such as blocked out lets.

Therefore I am certain that the appliance would detect rising outlet temperature and prevent unsafe operation or temperatures occurring or even consequential damage to the appliance.

As for the lack of a diverter plate in the heaters duct connections. The comparison to the Truma system is erroneous. The designs of the products are entirely different and may have different regulatory requirements placed upon them. it will have been a design choice, and certainly not a design defect.

 

[Gafferbill]

......I would contact Whale customer service and explain your problem.
They will know all the ins and outs of their equipment and do all they can to help.
They are known for their excellent customer service.

 

[trevormonty]

Thanks Buckman but I cannot close the front vents as they don't have a butterfly valve and the Whale unit manual states that they must remain open. However, the foil wrapping on the ducting is a good idea so I'll look into that

Why not use a small portable electric heater in bedroom.

 

[GaryB]

Why not use a small portable electric heater in bedroom.

We did similar a while ago with a small oil filled radiator when we had a 2014 Swift 586. It wasn’t ideal as it was something else to carry but it kept the end (where our daughter slept) warm.

 

[Andy Norfolk]

Does it perform the same on electric and gas? We found on our warm air blown system that on gas we got much better performance at the back of the van.