Hello,

I happened to find a heater control valve in a parts car which I removed. It was rather corroded and so I just took it in case there might be any possibility of refurbishing it. I cut the tube leading into the heater box vent-system to take it out. I'm guessing that from what I've read below this was probably a big mistake, as it's a capilary tube.

So... is there any hope of refurbishing this part and using it again, or is it worthless now? I must confess I don't quite understand how they work. What's the purpose of the capillary tube thermometer?

Thanks

Hi. The capilar work as temperature sensor. After the cutting, you need a new valve. The 144 valve can be adapted (and cost half of the 122).

You post the message as "heater for my beater"...

Is that to say originality is not you greatest concern? The heater control valve was stuck open in my 122, which is fine for winter, but unbearable for summer. So I went to my local hardware store and bought a water valve. Pulled the two hoses off the original heater control valve, and put the new water valve in-line between the two hoses.

OF course, it ain't original... but if I had a good heater control valve it would be a cake walk to make it right again. And I've gotta open the hood to turn the heater on or off. But it works great and is totally reliable.

-Matt

Well, I don't actually quite have a beater, it was just a rhyme I couldn't resist. Mine is far from stock/mint though, so I'm not quite as concerned with restoring every detail to exact stock, still it's nice to have things working the way they were intended.

Perhaps you could use a 240 valve in yours, instead of the manual-under the hood valve option you've got going now?

Since I drove vw busses for quite a while before this, the ammount of heat I get from my volvo is an amazing revolution. My present valve is not in fact broken, but I pulled this other one out as a spare because I have heard that they're hard to come by now. Having a manual only valve is a small price to pay considering I get such nice heat and defrost anyway.

Does the capillary tube have a fluid in it normally? I don't remember a fluid escaping when I bent and broke it off...

Thanks for the tips guys.

I think the tube has some minimal amount of Freon-like stuff in it. The pressure in the tube changes with temperature. Your water temp gauge works the same way.

Ooooh, do I hear ya about those VW bus heaters. I've had a '64, '68 and now a '79. The '79 actually has a blower motor and the heat exchangers are a bit larger, but it's still miserable in anything under 40 degrees F. You can probably use old Volvo heaters to make toast.

Ha,

Like you said in your article, it seems like they designed the first volvos around the heater box.

The problem with those vw bussess is that there's such a large cabin-space, and having to force the air all the way from the back, up that tube and out. It never worked for me until I was at full speed for about an hour on the highway!! I do kind of miss the days of starting out in the wet NW and pearing through a little three inch circle "defrost zone" on my windshield. OK... well maybe not!

My understanding is that the capilary tube acts a thermostat for
the cabin air temp. 140's have a similar set up.

I have assumed it does work within reason. I don't
find myself constantly regulating the cabin temp. manually
during the winter months unless the outside temp. is
in the sub zero range.

If you have cut the capilary tube off, you will now have a strictly
mechanical valve.
--
Alan

hfmb;

That capillary tube connects(ed) to a sensing bulb in the heater box. When working as designed, this allowed for a thermomechanical, closed loop, automatic control of the air temp coming from the heater box.

If your valve is leaking, you can still use the "new" one as a replacement if it doesn't leak, you will just need to adjust the temp totally manually, because there wont be any closed loop function (opinions vary on how well this worked in the first place...).

Next time, try to ask before cutting.

Cheers