Alde fluid - my plan

I recently changed the fluid in my Bailey.

Opened the drain (removed brass bung) and let it flow into a large bucket. Then opened each air vent until the flow stopped. Closed air vents. I inserted a short piece of garden size hose into the flow pipe in the header tank and gave short blasts of puff forcing out any water, (you could use one of the flo systems, used for winter drain downs). Once you can blow without any resistance then the system is empty. Do the same to the other pipe , in case there is any in that side of the system. Refit the brass drain bung.

Now here's the trick to fill the system with ease. Insert the hosepipe (about four or five inches) into the return pipe within the header tank. This will block the pipe from the header but act as a vent pipe during filling. Now slowly add the new fluid into the tank. As it goes in you may hear air escaping from the hose. Keep on filling until the header tank is full. Now open each air vent one at a time in order starting from the first one near the boiler, but ensuring that you top up the tank level as you do each one. Then remove the hosepipe. Turn on the pump and as the system circulates air will bubble out into the header. After a short while there will be just the fluid flowing and no air. You must keep the level topped up and only pour the fluid in slowly or you will introduce more air into the system that you are trying to clear.

My system only took about an hour to do. The van was tilted only slightly towards the drain and there was no need to tilt it to aid air removal.

kettling is caused by scale or sludge in a system, or by an faulty boiler thermostat causing the fluid to boil. That is the the noise you hear and it's sounds like a kettle, hence the name.

The five year fluid is compatible with the earlier one, so don't be too worried about any mixing, should you have not removed it all. If unsure, read the label, it tells you so.

How often does the system require bleeding. Can it just be topped up?

My last caravan we had for 6 years and 9 months. Bled it after the first few days away. At 21 months the system started to kettle as the original mix was way to weak - not my top up after bleeding. It was refilled at Alde - paid for by dealer who was reimbursed by manufacturer.

It did not need bleeding during the next 5 years and that was 600 nights usage.

I am considering a "home" Alde fluid change, feeling confident after reading this thread. I do have a question though. How to safely dispose of the waste fluid? Blue in my case as it is the vans 1st change.

You need a friendly garage as they have to deal with this type of toxic waste and they could dispose of it in the proper manner. It is important that it is disposed of properly.

My caravan is due to have its heating fluid change , I contacted Alde as I was told by my dealer that it was not necessary .Alde said that the caravan builders only put fluid in that should be change after 3 years for cheapness.You can take your caravan /motorhome to the Alde factory in Wellingborough they will drain off your system refill you system with the 5 year fluid then service the system,They also have a facility for an overnight stay with electric hook up all for £200 if required.

This gets more confusing by the day! I bought Aldes own anti freeze G13 and that states ready mixed onthe container! 

So if the system is not empty and Im not totally refilling, what alternative do Alde provide other than G13, which states ready mixed!,

Not sure why the confusion. If you can guarantee that you have a completely empty system, them you can just use the ready mixed anti-freeze. If you can't, which is most likely the case for most, then all you can do, is drain and flush the system until it drains clear and then add half the volume of the system with concentrated anti-freeze and top up with clean water as required. If you're just topping up, then use  concentrated anti-freeze ..... Just the same as if you were replacing anti-freeze in your car. 

I successfully used a very simple method to changed the fluid in my Lunar Lexon 540 Alde heating system. I'm sure this approach can be used on similar lunar models and other makes. No extra pump is needed and there little chance of air entering the system, hence you should not need to bleed the system after replacing the antifreeze.

Remove the plastic cover around  the fluid tank. Mine was situated in the wardrobe. Unscrew the tank lid and remove the pump, unclip it's electric connector and place pump safely out of the way. Now use a thin bore plastic pipe to syphon out the fluid in the tank to enable the tank to be removed without spilling fluid. Unscrew the screws holding the tank to the wall. Compress, and move down, the metal clips around the top of the rubber connectors, between the tank and the inlet and exit pipes. Remove the tank.

You now need to fix a large plastic funnel to one of the pipes to feed new fluid into the system. The connection between the funnel and the pipe will need to be water tight. I used  a short length of plastic tube between the funnel and a short length of 22mm copper pipe, held together with tape and clips. The copper pipe should fit snuggly into the top of the rubber connector on one of the heating pipes.

You will also need to attach a further length of plastic pipe to the other heating pipe to feed the old fluid into a bowl or bucket. I used a 22mm right angle copper bend to connect the plastic pipe to the rubber connector on the central heating pipe. You need to ensure the outlet pipe is positioned lower than the funnel to give a head to force the liquid around the system. Making up the connectors is the hard part , the rest is easy!

My system holds approx. 13l of fluid. I poured 15l of deionised water (cheap at Tesco) into the funnel. Gravity forces the water around the system and into the waste bucket. I followed this with 6l of triple Q G13 concentrated antifreeze. The two will mix in time to give the right 60/40 mix. The whole process should take no more than half an hour. Remove the funnel etc and replace the tank. Fill it to the mark with de-ioned water. Replace the pump. Job done!

Except, the void in the boiler is just that so the fluid flow will take the easiest route thus no guaranty all or even most of its contents will be displaced. A reason why draining the boiler is the recommended practice.

Also Triple Q G13 I understand is not approved by VW to their VW TL 774 J  , the definitive G13 spec fluid, recommended by Alde.