T25 1990 Internal front heater control - mystery

[Bison535]

I have been trying to Shut Off the heat from the front cab heater without success

I have read some of the Topics re the heater and looked through the handbook i.e. the 2nd lever down is the hot water control to the heater element. Fully to the left and I still get heat !!!!???
I have since taken out the spare wheel and checked the valve operation, seems ok. I have also resorted to putting clamps on both inlet and outlet pipes to stop water flow, still I get heat !?
I thought maybe heat/hot air could be coming in from the main radiator, therefore I have inspected the area aft of the fan housing and taped up any possible entry places, but, still I get hot air from cab vents !!

In a hot climate this is doubly troublesome, has anyone got any ideas and or a solution please

[bigbadbob76]

Sorry if I'm missing something here but as you say "in a hot climate" the incoming air will be hot.
Unless you have air conditioning there's no way to cool it down.
Am I being over simplistic?

[Bison535]

Yes I understand your point, the ambient air temp is relatively 'cool', but the air from the cab/front heater is/remains quite hot. Im in mid Portugal just now, the sun is hot but air temp is still coolish and very cold at night.

Its still a 'heater problem' i cant fathom

[colinthefox]

The heater control valve has to shut off completely to produce ambient air from the heater. If it's "letting by" even a tiny bit of hot water you will get the symptoms you describe.

It could be due to the cable inner being a bit bent, a stiff mechanism, or something out of adjustment. The way to check would be to disconnect the cable from the valve, move both the valve and control to the "cold" position, then see if their positions coincide, if you see what I mean.

If with the mech. disconnected and the valve fully closed, it still produces heat then the valve is letting by and needs replacing. You should be able to feel the pipes to see if hot water is getting past the valve.

[Oldiebut goodie]

According to my handbook the heat lever to the left is full heat!

[captain Byrne]

According to my handbook the heat lever to the left is full heat!

Are you sure OBG, my levers go left for no heat?

[Oldiebut goodie]

Just posted the page!
That is a lever that doesn't have a corresponding graded graphic.

[Oldiebut goodie]

How odd - I have just physically checked mine and yes on the right there is a square with red in it denoting heat! Can't remember when I last altered those levers as I just use the Webasto if I need heat /defrost etc.
Either the manual is incorrect or there are 2 versions.
I am now confused.

On the next page it mentions moving the lever to the right into the heat zone so that must be a printing error. It would be interesting to see what other people's manuals state.

[RogerT]

If you pop out the radio and the ashtray, you'll see the clamps screw for the cable outer. Loosen it a bit and pull through more outer towards the lever. Re-tighten. Then when your lever goes over (to the left!) to close off the valve it is pushing more cable into the outer, and in theory closing the valve more. Probably easier than rooting around under the van, unless you're under there already. Had to do mine as I had the same symptom, and it's helped but not cured, so I'll have to do it again.

That manual pic, that's a LHD (sorry - stating the obvious...) so I reckon the heat control lever would be the opposite way round so that the cable can exit the mechanism on the right to go down in front of the gearstick? Maybe?

[Oldiebut goodie]

None of the others are the other way round though, you would expect them all to be reversed. It must be a misprint.

[RogerT]

Stamps with a misprint can be worth thousands. Wonder if it's the same with manuals?

[Superal]

on campervan culture they have a sticker you can buy with the following cold to the left:-

http://campervanculture.com/shop/instru ... -controls/

[captain Byrne]

on campervan culture they have a sticker you can buy with the following cold to the left:-

http://campervanculture.com/shop/instru ... -controls/

From someone who suffers from heater control dyslexia, that is really handy.

[Aidan]

often if the dash has been out and not been correctly reassembled or if the heater valve has failed then the cable gets bent so it wont slide into the sheath it just bends when you move the lever to the left and doesn't operate the valve, you need two people to check the operation, one in the cab moving the lever and one person with the spare wheel carrier dropped down and a torch looking at the lever arm on the valve behind the radiator to see that it is actually working and if it appears to be working that it is actually moving the valve not simply moving the plastic arm which is stripped where it is attached to the valve, the screw head must move
if the solid cable is bent then replace it with a new one, or a good used one as once it's bent no amount of straightening it will generally get it to work properly again, ime

[Bison535]

Hi to all of you who kindly responded, first OBG's photo of heating controls, my heater control is opposite i.e. Heat is full to the right and off to the left. All very confusing.

I have tried both 'left' and 'right' positions and still get heat! My method now is to 'plug' the vents to stop the hot air

I have taken out ash tray and radio but all looks ok there, and looks tricky to adjust outer cable ???? for hot water valve control. My lever/cable/valve all seem to be moving/operating ok.

Anyway, all of the comments and the fact that I have clamped both inlet and outlet rubber pipes to the heater still remains a mystery why the heater is still producing 'hot air' when I only need 'cool air'

The problem still exists, any more thoughts please?

Im in Portugal just now, but when I reach UK next month I will need to get the problem resolved so that I can get Hot or Cool on demand.

T25 1990