Hoover Keymatic!!

[chestermikeuk]

Yes , didnt make that clear in last post , this slope front Hot & Cold Keymatic has different water levels for wash & rinse on individual pressure switches which determine low & high water levels.

The later Keymatics had one pressure switch with multiple levels low medium & high

It's certainly a heads scratcher at times to work on if you think this series had 4 timers and six wiring loom upgrades for two models over 5 years of production

 

[gizmo]

I absolutely love Keymatics, but really they weren't very good machines.
They were unnecessarily complicated and quite unreliable.
The wash action is poor due to the tub tilting backwards when full and the extremely high water level, the clothes aren't so much lifted out of the water and dropped back in it, more sort of tumbled in deep water, which isn't as good an action. The wash time on standard cycles is only 4 minutes, though the machine tumbles during the heating phase too which helps. (I think they alternately tumble and heat, not both together?? It's been too long, I'm not certain of that.) I don't think the pulsator adds much to the wash, it's just below the water surface and much smaller diameter than the Hoovermatic twin tub pulsator. The one-way only tumbling doesn't help, either.
The very last versions in UK had a 4th rinse, there would be a reason for that... The Aussie ones were always 3 rinses, AFAIK we never got a 4th rinse version. Aussies are very water conscious. There was only one, 15 second intermediate spin, though the rinses were deep.

One good thing about them was the lack of vibration on spin - the cable suspended drum could shake about on spin, but it didn't transfer to the body of the washer. They were on wheels, so the excellent soft suspension was needed so they didn't wander.

The two pressure switches reflect the technology of the time - they were each single stage pressure switches. Later technology gave us two and three stage pressure switches, and later again, infinitely variable pressure sensors.

In the Keymatic, the low level pressure switch turned on the tumbling when the water reached the low level, but fill continued (may have a change of fill temperature, depending on the cycle) until the high level switch clicked over, which turned off the water and turned on the heater, if needed.
During Tumble phases the pulsator clutch solenoid is activated to prevent the pulsator turning, during the actual wash or rinse phase (in cycles that use the pulsator), the pulsator clutch releases, which allows the pulsator to turn - the solenoid is activated to prevent pusator action. The pulsator is only allowed to drive when the high level pressure switch is satisfied.

When pumping out, the timer does not advance to spin until the low level pressure switch has reset. (actually after pressure switch resets, it moves to distribute the load by tumbling for 15 seconds, then the timer advances to spin, where the main motor instantly reverses to spin the load.

 

[Chetlaham]

Interesting, I will start a new thread on the subject of how Keymatics worked.

 

[chestermikeuk]

I absolutely love Keymatics, but really they weren't very good machines.
They were unnecessarily complicated and quite unreliable.
The wash action is poor due to the tub tilting backwards when full and the extremely high water level, the clothes aren't so much lifted out of the water and dropped back in it, more sort of tumbled in deep water, which isn't as good an action. The wash time on standard cycles is only 4 minutes, though the machine tumbles during the heating phase too which helps. (I think they alternately tumble and heat, not both together?? It's been too long, I'm not certain of that.) I don't think the pulsator adds much to the wash, it's just below the water surface and much smaller diameter than the Hoovermatic twin tub pulsator. The one-way only tumbling doesn't help, either.
The very last versions in UK had a 4th rinse, there would be a reason for that... The Aussie ones were always 3 rinses, AFAIK we never got a 4th rinse version. Aussies are very water conscious. There was only one, 15 second intermediate spin, though the rinses were deep.

One good thing about them was the lack of vibration on spin - the cable suspended drum could shake about on spin, but it didn't transfer to the body of the washer. They were on wheels, so the excellent soft suspension was needed so they didn't wander.

The two pressure switches reflect the technology of the time - they were each single stage pressure switches. Later technology gave us two and three stage pressure switches, and later again, infinitely variable pressure sensors.

In the Keymatic, the low level pressure switch turned on the tumbling when the water reached the low level, but fill continued (may have a change of fill temperature, depending on the cycle) until the high level switch clicked over, which turned off the water and turned on the heater, if needed.
During Tumble phases the pulsator clutch solenoid is activated to prevent the pulsator turning, during the actual wash or rinse phase (in cycles that use the pulsator), the pulsator clutch releases, which allows the pulsator to turn - the solenoid is activated to prevent pusator action. The pulsator is only allowed to drive when the high level pressure switch is satisfied.

When pumping out, the timer does not advance to spin until the low level pressure switch has reset. (actually after pressure switch resets, it moves to distribute the load by tumbling for 15 seconds, then the timer advances to spin, where the main motor instantly reverses to spin the load.

Was the last Aus Keymatic the model with the teak fascia Chris ?

My Aunt & Uncle moved out to Melbourne with work 1966 and it was only recently she saw one of my pics and said they had that Keymatic in their first rental when the moved there

She said it was really good washer and didnt have any trouble or repairs the time they were there .

 

[gizmo]

There was a model with a teak fascia?
If so, it would have just been a fake woodgrain sticker, but I don't remember one.

 

[Chetlaham]

This is how I imagine the modern Hoover Keymatic design. The machine has three mal-operation relays- two deal with an out of balance load that trip and hold open, the other monitors motor current and will trip and lock open before the motor's internal overload does for a suds lock or excessive tub drag situation. The three relays re-set every time the motor is de-energized when switching in between cycles. This allows one failed spin not to effect the others. If routine spins trip out the relays, the timer continues to advance the cycle as normal until hitting off. This is a limp along feature that allows the cycle to finish without error codes of shutting down the whole machine.

There are two water valves in series for flood protection redundancy like on older Maytag and Hobart dishwashers.

A second pressure switch acting as flood prevention breaks the circuit to the water valves should the main pressure switch fail. The backup flood prevention pressure switch is fed via separate dome and sensing hose. It would be a discrete color from the normal pressure switch hose.

The wash temp is determined by the time allocated for heating. Cottons and Heavy give more time, delicate gives less time that contact CAM 5 8B pink is closed. Crude, but very simple and reliable. Heater only runs once the main pressure switch is satisfied.

16/2 pole motor so electronics to fail. The single pole double pole counter-clockwise motor rotation timer contact cam #8 position M14 engages 14T RED during the final drain increment and then immediately falls into 14B Tan shitting the machine from tumble to spin instantly. Doing so prevent garments from clumping up at the bottom before the spin reducing the possibility of an out of balance.

At the start of drain a door lock wax motor is engaged. If the motor successfully actuates with the door seated correctly the door lock spin enable switch closes. Upon removal of power to the machine or door lock wax motor, the motor takes about 2-3 minutes to re-tract. This is so the machine basket has enough time to coast down at the cessation of spin before the door can be opened.

There is of course a re-circulation pump that runs in wash and rinse which prevents detergent from settling down in the drain boot.


Tumble reverses every 60, 90 or 120 second 7.5 degree increment of the timer.