Custom combined heater and airconditioning unit

After a successful flow test of a combined heater and aircon unit I just had to finish heater V2. So I started replacing cardboard and duct tape with sheet metal.

01.Kachelbehuizing van karton naar metaal

And added the bottom.

02.Kachelbehuizing onderkant

and TIG welding the whole thing.

03.TIG lassen kachelbehuizing

At the lowest point I added two drain tubes.

04.Kachel condenswater afvoer

And test fitted the whole thing with the modern evaporator.

05.Kachel aircoverdamper passen

It did fit but was quite tight. The aluminum evaporator directly toughed the metal casing at some areas. Over there cold would leak away. Therefore I created some more space around it to be able to add isolation material.

06.Kachel aircoverdamper meer ruimte isolatie

07.Kachel aircoverdamper verhoogd

I added deflectors on the inside to ensure a optimum flow from the blowers towards the evaporator.

08.Kachel airflow binnenkant

Window demist connection

Next to the side and front vent outlet having front window demist is required for the MOT. my idea was to make a splitter with a valve so I made a bushing on the lathe.

09.Kachel asbus draaien

And welded it onto the tube.

10.Kachel asbus op uitstroomklep

For the other side I also made one also at the exacte right inner diameter for the axle.

11.Kachel asbus2

Which therefore exactly fitted. I added a groove for a locking clip.

12.Kachel uitstroomklep as

Next, I used the mill to flatten one part of the axle to be able to attach a flap.

13.Kachel vlak kantje aan as

That allows me to open and close the front window demist flow.

15.Kachel ruitenontwaseming klep

14.Kachel vlak kantje aan as en erin

Another testfit under the dash.

16.Kachel ruitenontwaseming klep onder dash

One ventilation hose will go across the heater and the other one almost directly goes into the stock outlet.

17.Kachel ruitenontwaseming klep gehecht

To make sure not all airs flows towards the front outlet all the time, I needed to add a flap..

18.Kachel voorklep v1

With the hinge on top it would be easiest to build the controls. However that was not really an option since in the open position a large proportion of the airconditioning evaporator was blocked.

19.Kachel voorklep v1 kan niet

So the front flap hinge needs to be at the bottom. But it was time for another flow test first.

20.Kachel voorklep onderkant en flowtest

Unfortunately even with the sides and front outlet blocked there was hardly any flow towards the front window demist. Relying on just over pressure is not enough. To have a proper demist function I need to build on the flow direction. Time for a new plan.

21.Kachel voorruit uitstroom v2

Attaching the hose connections directly onto the sloping front without any valves.

22.Kachel voorruit uitstroom v2 gehecht

While having the front flap hinge at the bottom. I made some axle bushings, stud welded some bolts and used some clamps from 220V plugs.

23.Kachel voorklep scharnier

So front flap V2 emerged.

24.Kachel voorklep v2

I found a nice lever for the controls.

25.Kachel voorklep hevel

However it turned out moving the lever was quite heavy and getting the cable in was difficult. So I used the old choke mechanism and another lever.

26.Kachel voorklep hevel v2

Now the controls operate nicely!

And also the new flow test was successful.

Now only the last bits and pieces for the heater need to be done.

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OldVolvo is a classic Volvo hobby blog by Lars Rengersen.

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