ALDE heating question

[Surfer]

Where is the thermostat located for the heating? We have the 2011 Lunar Delta TI and used it this weekend when the temperature dipped below zero. It took nearly 24 hours for the caravan to heat up right through.
We had the temp set for 30C, but it was hardly warm. On setting it to 25C, it warmed up the caravan much better, but a number of cold spots. We did notice that on the bunks in the front by the bulkhead that the woodwork was extremely warm even hot in some areas, but there are no vents for this hot air from underneath. The concern is that this heat will eventually dry out the wood causing a lot of damage.
The caravan had only just come back from a service so I tried bleeding the system, but it made no difference. The only thing I could think of was that the issue was with the thermometer not working correctly and shutting off too soon.
Any suggestions?

 

[Martin_E]

Unless you have a remote thermostat its in the control pannel.

It could be you have an air lock or a bubble under the 12v pump, so its not pushing the fluid around as it should

 

[JTQ]

If the circulating pump is running then its not a thermostat issue, as that is all the room stat does switch on and off the pump.
If you have hot water then the boiler itself is working.
You need to check that the pump is actually circulating the inhibited water, This pump is only capable of doing that if there are no air locks in the circuit. So check everywhere you can that the circuit pipework is hot, not just warm but hot after the system has been on for 30 minutes. If it is not you have an airlock and join the club as IMO it is nearly always the reason the system malfunctions.Too many dealers simply fail to bleed the system properly.
The ALDE system is capable of a very high heat output [7 to 9 kW depending on gas used and element pack fitted] and if it was working correctly the last thing you would publish here is a comment about its inadequacy.
Properly bleeding it can be a DIY job but would take a page to detail. A good dealer has a special bleeding/purging pump that can do it in minutes. After bleeding the owner needs to monitor and top up the fluid untill it really settles down, failing to do this can drag in new air locks.
Hope that helps.

 

[RogerL]

Do you have a link to a "page" on how to bleed the Alde properly?
I'm about to order a caravan that will have Alde fitted as OE and it would drive me spare if I couldn't bleed it properly.

 

[JTQ]

Roger,

I
would have to write it up or find where I have published it on forums in the
past.

So bear with me and when it’s convenient
I will rewrite or find it for you.

Make
sure in your immediate dealings you identify where all the system bleeders are
and how you get to them. Mine required finding how to disassemble some bits of
furniture.

A dealer serious about servicing Alde systems [is
yours] invests in a purging pump that sweeps the air through the system which
up to a point does not involve this bleeder attention.

With a DIY bleeding we
only have the static head as the motive force to move the air to accessible
bleeders.It is not difficult but tedious and requires a systematic attitude.

Don’t
have a moments doubt about having the system as its very good.

 

[RogerL]

I'm no doubt being naive - but shouldn't a single pipe system leave all it's air in radiator(s) or the header tank ? That's obviously assuming that fluid is in the pump.

 

[hortimech]

You could always try here: http://www.alde.co.uk/manuals.php

 

[JTQ]

I'm no doubt being naive - but shouldn't a single pipe system leave all it's air in radiator(s) or the header tank ? That's obviously assuming that fluid is in the pump.

Sadly yes you are; this is
because that pipe system in reality has its ups and downs, literally

It needs to climb over
holes punched through furniture and probably as in my case rise to service a
radiator raised up a wall. Note the radiators are in most areas simply the tube
with push on finning, not a domestic unit where it has height to a built in
bleeder. My bleeders are simply plastic tube risers off critical parts of the
circuit, possible 7 in all. They are not bleeders on rad headers as in the
home.

The summation of these
multitude of rise and falls, where air is trapped then clearly equates to a “head” way above the
miniscule pump head of the circulating pump. You will say then put in a pump
with greater head then, but that would be both noisy and energy sapping and
once fully primed then the head needed to circulate is actually minimal. The equipped
workshop or Alde engineer carries that portable powerful pump and in short time
blows all the air to release in the header. This works well but it does not
scavenge air trapped in the spur risers to the bleeders and ideally these
should be bled.

If they are not bled the
system though operating has the compliance given by the trapped air and this
expands as it heats up. Therefore a system in that state exhibits large changes
in the header level hot to cold and if moderately filled can well spit out
fluid. This expanding trapped air is also prone to ease out into the flow,
particularly after a service, hopefully as small bubbles to be swept along and
released in the header, but all too often I believe to coalesce as an air lock.
So you come home from a service only for it to air lock next or second time
out.

Hope that gives a bit more
insight to how I understand the system works.

Apologise to those that
are upset by my grammar spelling etc I am very challenged in that area but well-practiced
in fluid engineering. .

 

[RogerL]

From the link:-
"Stop the circulation
pump. Lower the front of the caravan as
far as possible. Leave it in this position
for a few minutes to allow the air to travel
upwards in the system. Open the bleeder
screw at the highest point. Leave it open
until it discharges glycol fluid. Raise the
front of the caravan as far as possible and
repeat the procedure in this position. Then
position the caravan horizontally and start
the circulation pump. Check that the pipes
and radiators around the vehicle are heating
up."

 

[hortimech]

As far as I can see, this system is mostly just a pipe running around the caravan, the large number of bleed pipes could be part of the problem. A small pump should be able to move the fluid around the system without any problems, you just need proper bleed valves at the highest points on the system. The main problem that I have with system is that the fluid is highly poisonous and is tied into the hot water system which has a common source with the cold water.

 

[Surfer]

From the link:-
"Stop the circulation
pump. Lower the front of the caravan as
far as possible. Leave it in this position
for a few minutes to allow the air to travel
upwards in the system. Open the bleeder
screw at the highest point. Leave it open
until it discharges glycol fluid. Raise the
front of the caravan as far as possible and
repeat the procedure in this position. Then
position the caravan horizontally and start
the circulation pump. Check that the pipes
and radiators around the vehicle are heating
up."

Makes sense unless you have a twin axle. I don't think you will have any issues with yours. We can hardly hear our pump running. It is just an issue with the heat distribution as ours is a twin axle and probably similar heat configuration to a single axle. We only have 2Kw heating, but I believe the new caravsn have 3Kw. Not sure if ther will be any difference.

 

[TonyG]

SSurfer we have a conqueror 645 and our Alde heating was very hit and miss, after contacting our dealer it turned our that the Alde thermostat was behind the cupboard above the fridge... And as the fridge gives off heat the heating would turn itself off as it believed it had reached temp.
ourdearler repositioned the thermostat and now all is OK. Sorry don't know where it is located on the lunar

 

[philspot1]

JTQ - Please don't apologise - I am a compulsive nit-picker, but I found your explanation extremely clear and perfectly laid -out. If only we could all do so well!!