Heater and vacum pipe help

[EmlynTaylor]

Afternoon all.

 

Dec1 and I need my heater.  I decided that having no heat was really no longer viable ... ice on the inside of windscreen makes driving a challange.

 

I traced the heater (hot cold) dial/knob to behind the accelerator pedal (of all places) and have (after disconnecting from dial) moved it to fully open and still no heat...The pipes near what I guess is some type of diverter valve are real hot but still no heat...tried it fully closed too.  Any ideas?

 

Then I decided to 'fiddle' in stereo hole and spotted a couple of vacum elbows that I thought id check, in the middle of fiddle I managed to disconnect a vacum pipe withouit noticing where the other end comes from , any help much appreciated,

Edited December 1, 2012 by Emlyn Taylor

[mdw]

Full forum membership gets you access to the parts manuals which will show  you the exact route for the pipes.  Probably a good idea to chase them right through and check the lot.  Plus when I did mine there was a tiny (1mm) bit of muck in the little actuator valves causing a problem.

Could also be the matrix is blocked. Get underneath disconnect the 2 small  hoses that go up from the front of the chassis then open the heater valve and back flush the matrix with a hose.

Edited December 1, 2012 by mdw

[fflyingdog]

I think the pipe that you have disconnected leads to the fresh air actuator (which is itself situated in the front 'bonnet' area in the fan area )

[Paul93Lotus]

Most problems can be traced to those elbows. They are prone to rot with age and are of lower quality. Look for a tight fit on all elbows.

[Qavion]

I just discovered the cause of a longstanding heater problem on my 1989 SE that I thought was going to cost me thou$ands.

The vacuum hoses were ok, but a vacuum switch (valve), which controls the mode flap was dislodged. The mode flap allows air flow over the heater matrix and into the cabin (for demisting, etc).

When you turn the right hand (large knob), a cable(?) operates a cam (visible in the drivers footwell, near the lower rubber heater pipe). The cam should push on the plunger of a vacuum switch when the right hand knob is at 12 o'clock. The vacuum switch is held in with 2 phillips screws, so easy to reposition.

http://www.iinet.net.au/~b744er@ozemail.com.au/Lotus/ModeFlapControl.jpg

Total cost = almost nil (just time and a few Band Aids for scratches from zip ties )

Cheers

Ian

Edited January 1, 2013 by Qavion

[emlynt]

I think the pipe that you have disconnected leads to the fresh air actuator (which is itself situated in the front 'bonnet' area in the fan area )

Does anyone know of a diagram that shows where abouts under the dash the elbows are?  Also what does the fresh air activator look like...need to know this to see if vacuum is disconnected from here

 

thanks

 

E

I just discovered the cause of a longstanding heater problem on my 1989 SE that I thought was going to cost me thou$ands.

The vacuum hoses were ok, but a vacuum switch (valve), which controls the mode flap was dislodged. The mode flap allows air flow over the heater matrix and into the cabin (for demisting, etc).

When you turn the right hand (large knob), a cable(?) operates a cam (visible in the drivers footwell, near the lower rubber heater pipe). The cam should push on the plunger of a vacuum switch when the right hand knob is at 12 o'clock. The vacuum switch is held in with 2 phillips screws, so easy to reposition.

http://www.iinet.net.au/~b744er@ozemail.com.au/Lotus/ModeFlapControl.jpg

Total cost = almost nil (just time and a few Band Aids for scratches from zip ties )

Cheers

Ian

Now fixed, the vacuum pipe needed to be connected to the Mode Flap Control in your diagram

 

Thanks Ian!

 

E

[espritmania]

Where is it best to bleed these pipes? Does anyone know if there are pictures posted on the forum? Thanks.

[andydclements]

Do you mean, bleed the vacuum pipes?

If so, then there is no such job.

[mdw]

Sorry if I have confused things. The pipes that may need bleeding are the water hoses into the r/h side of the matrix. The 2 hoses circled are the ones to look at. One is from the valve which is on top of the pedal box and almost impossible to get at.  The rusty metal rod at an angle at the bottom is the accelerator pedal arm that attaches to the cable ( not the one with the pedal on the end of it).

Edited December 7, 2013 by mdw

[espritmania]

Thanks.