Heater/air con

[mt308]

Have been using the heater a fair bit lately which works pretty well. No shortage of heat being generated by the engine!

However I find after pushing the switch fully home into the cold position and leaving the fan on that the air is still quite warm and remains so for as long as you keep the fan on. This is quite a good setting for winter driving once the interior has warmed up initialy.

This presumably means that in the Summer time the air con is fighting against fairly hot air within the unit making it less effective cooling the car and meaning more use of air con than would otherwise be the case. I am thinking if I could solve this issue the car will be a lot cooler in Summer.

The most obvious issue would be the shut off valve not closing sufficiently.

I've not investigated as yet properly, but is this something others have also found, and any fixes out there?

Cheers

Mark

[davefiddes]

Do you have an H-pipe in the heater circuit?

I didn't have one originally and the air blowing through the heater matrix was always a little bit warm. Fitting an H-pipe in the heater circuit gives somewhere for the pressure to go when the heater valve is shut. With this fitted the heater matrix stays cold.

Another potential problem might be the heater valve plumbing. IIRC the valve has clear markings for the expected flow direction. It's not beyond the realms of possibility that plumbing it the wrong way round will be letting flow through (more than designed - the valve does have a small pilot hole to let flow through all the time).

[mt308]

davefiddes said:

Do you have an H-pipe in the heater circuit?

I didn't have one originally and the air blowing through the heater matrix was always a little bit warm. Fitting an H-pipe in the heater circuit gives somewhere for the pressure to go when the heater valve is shut. With this fitted the heater matrix stays cold.

Another potential problem might be the heater valve plumbing. IIRC the valve has clear markings for the expected flow direction. It's not beyond the realms of possibility that plumbing it the wrong way round will be letting flow through (more than designed - the valve does have a small pilot hole to let flow through all the time).

Yes I have an H pipe on the rear bulkhead.

The valve being on he wrong way around is something I will have a look at tomorrow.

Thanks

[Storer]

It may be worth fitting a valve on the return side of the heater too.



Paul

[F.C.]

I have fitted two valves to mine to stop this happening,
It is unlikely to be a directional problem as the valve is of the barrel variety.
I plan to replace mine with solenoid valves at some stage.

[mt308]

F.C. said:

I have fitted two valves to mine to stop this happening,
It is unlikely to be a directional problem as the valve is of the barrel variety.
I plan to replace mine with solenoid valves at some stage.

Did you fit the same valve again as the existing one? How do you connect the second valve?

Thanks

Matk

[Paul.B]

Getting the valve to close fully by just pushing in the lever can take some fine adjustment. If you reach into the side pod after closing the valve, you may find some further movement if you push the valve closed by hand. Basically the cable doesn't always fully close it. Getting the existing one to fully close is the first step. Fitting a second one will help.

[Storer]

Mine is electric. Can't abide those damn cable type controls!


Paul

[UltimaCH]

Mine will be electric also. Don't like that cable operated contraption, even if it works correctly I imagine.

[F.C.]

mt308 said:

Did you fit the same valve again as the existing one? How do you connect the second valve?

Thanks

Matk

I fitted a near identical valve (CBS I think) on the return line I used the bellcrank pivot on the original valve to connect to the second valve bellcrank, the knob operation is a little stiffer but there is no bleed through to the heater matrix now.
If I were you I'd source a solenoid valve and do away with the mechanical valve altogether, this route is a far simpler solution and can move the valve position from side pod to under rear clam.
I'm kicking myself for not doing it before now.

[mt308]

Just taken a look and it is simply the valve not being pushed back quite far enough when the interior button/lever is pushed home. Probably when cables got organised towards the end of the build it changed the amount of play available.

I guess I now need to unravel the coiled up cable that goes over the valve switch and making it slightly longer. A job for another day...

Quite happy that this should now mean my air con is much more effective as it must have previously been battling with fairly hot water coming from the heater circuit.

The current set up once I get it to work suits me fine. Everything easy to adjust from the drivers seat. For me the simplicity and lack of unecessary over-engineering was part of the appeal of the Ultima. Each to his own of course!

I used to have an MG Midget where the heater control involved stopping the car, opening the bonnet and turning a tap on the cylinder head!

[F.C.]

mt308 said:

I used to have an MG Midget where the heater control involved stopping the car, opening the bonnet and turning a tap on the cylinder head!

been there done that!

[Steve_D]

mt308 said:

.....I guess I now need to unravel the coiled up cable that goes over the valve switch and making it slightly longer. A job for another day...

Just move the outer cable in the clamp on the valve. If you set it so that when the valve is closed the knob is still sticking 4mm out of the dash you will be good to go. When you push the knob right into the dash the 4mm 'Spring' will ensure the valve is fully closed.

Steve

[EddyP]

Storer said:

Mine is electric. Can't abide those damn cable type controls!


Paul

Hi Paul,

What sort of electric valve did you use and how are you controlling it?
Is it just on/off or variable?

Thanks

[UltimaCH]

Ed, PM sent!

[ROWDYRENAULT]

Vintage Air makes an electric valve that is variable opening, fits the hoses and is a hell of a lot easier to package into the side pod. Also because your not dealing with cables you can run the control knob any where you want. Most of the time getting away from the build as set by the factory causes headaches, this is one mod that's actually easier to do then the factory solution. Lee

[Storer]

Hi Ed

Mine is a Vintage Air valve and is adjustable (as far as the system allows adjustment).

Works well but control looks a little retro....



Paul