Hi Big Roy
It is no secret I and a few others , Jo-anne, have been plagued with this problem.
Whilst protocol and confidentiality preclude me from naming, I can tell you my investigations lead me to believe the source of the problem rests with the window frame manufacturers, Polyplastic.
And you will recall it was Swift and Polyplastic who slammed the door in our faces.
I invite Polyplastic or Swift to correct me if what I now say is incorrect but I emphasise it is all based on my own personal investigations and no one else.
It seems the window systems are thermally broken during manufacture. This is an expensive process but the intention is to isolate temperature transmission from the cold outside to the warmer inside.
This is supposed to stop condensation.
Somewhere during the production process the thermal breakage is not being done correctly or some other intervening factor is causing partial bridging leading to the condensation.
It may be the rubber seals are acting as a bridge but in my view as rubber is not a good temperature transmitter I cannot follow that logic.
Aluminium is probably not the best material to use although aesthetically it looks pretty. That doesn't bother me and would not even be a minor issue in choosing my caravan.
I can only conclude a batch of Polyplastic aluminium window frames sent to Swift and other manufacturers are faulty . However short of removing the frames myself , which I am not qualified to do, I cannot prove my thesis is correct.
It will be interesting to see if your dealer's solution works.
Meanwhile I can only reiterate my extreme disappointment that Polyplastic will not take an active role and try and help those of us who have a problem with their aluminium frames.
Hopefully the problem will subside in the spring and summer but then we have the autumn and winter again.
Finally, yes I know I can pursue this further with my dealer but quite frankly I doubt this is one for them at the moment.
Until Polyplastic come up with an admission and proposal for resolution we are wasting our time.
This is the 109th post on this thread and I think Polyplastic should now show us what they are made of.
Cheers
Alan
Hello Alan,
Let me make it clear that I am not employed by Swift or Polyplastic, or obliged to them in any way. The views I express here are my own.
I personally believe that metal window frames are not the best choice for a a small living volume with a low thermal mass, and a limited heat input rate, and an intermittent and low occupancy rating with relatively high percentage of fixed ventilation.. The temperature regime has a tendency to be quite wild compared to a normal domestic house. These are conditions that will tend to exacerbate issues with condensation.
There are relatively few designed products that don't involve compromises of some sort. In the case of a caravan, to achieve a level of thermal mass that would help to stabilise the temperature and thus help control condensation, it would require a caravan of such weight that it would be impractically heavy. So the use of light weight insulation helps to reduce heat loss but equally it has no temperature stableising action. This means that the temperature in the caravan can have quite large extremes, and it can change quite rapidly when a door or a window is opened.
These are all contributing factors (amongst others) that can lead to condensation occurring.
Just to correct a couple of technical points that you make in your posting:
Para 2. Heat transfer does not go from cold to hot but always hot to cold. Energy always moves naturally from high energy state towards a lower state.
Para 3. The reason for providing a thermal break is fundamentally to reduce heat loss. This is to reduce energy requirements. It is a serendipitous but desirable effect if it also reduced the potential for condensation.
Unlike you, I have not had the opportunity to even see one of these windows, but I will bet they are manufactured from an aluminium extrusion, and probably anodised or coated.
Assuming I am correct about the form of the frame, the construction of the window frames will be closely controlled. The shape of the frame will be created on jigs or numerically controlled forming machines which will hold tolerances well in check. It will also be a feature of these jigs that
the raw extrusion will have to be of the correct cross section form for it to be engaged in the machine or jig before it can be bent to shape. Thus I find it very difficult to believe that the window frames have been manufactured incorrectly, i.e. the break has been bridged.
Equally I am sure that Swifts designers are aware of the need to maintain the integrity of the thermal break, however I have less confidence about some of their production techniques, and operatives who might not understand the need for the break and with little incentive to maintain quality (as they are on 'piece work') through ignorance they might be compromising the break when they fit the frames to the caravan. However it is unlikely that the entire thermal break would be compromised, most likely just a few points around the frame were fixings are used.. In all it is likely to be less than 10% of the frame that might be compromised.
Whilst it would be great if the cause your problem cold be pinpointed to a particular product where changing it resolves the issue, but I believe it is most likely to be the result of a wider range of factors.
I realise this is of little comfort to you but I feel it is important to forewarn you before you get you hopes too high..