Stenner stair lift battery and safety sensors.

[ericmark]

My mother hardly uses the stenner stair lift so no idea when the fault happened. I came to change a toilet and thought easy way to take the old loo down stairs was on the stair lift. It actually went about on meter before stopping.

First thought was maybe not been on the charging station so wound it back to station. Week latter still not working so time to look further.

Removing front cover I found the replacement batteries fitted at last service had smaller spade connectors than original and the so called engineer had pushed on the connector with the spade between the insulator and connector rather than the correct metal gripping part.

Quick bending with pliers and now good connection to battery. But still stair lift not working. Tested voltage on battery 27.4 volts power off and 27.6 volts power on and disconnect and getting 29.6 volt so clearly now charging.

Wound the chair off station and tried all safety switches wound back onto station removed power unplugged battery re-connected battery and switched on power and at last it worked.

I ran the chair about one meter from the charge station twice and back again and all seemed to work but decided to leave on charge before further tests if you have ever tried to manually wind the chair you would realise why I don't want it to fail.

It seems likely it was simply a bad connection on the battery but rather worried easy enough to carry the loo down stairs but to carry my mother would mean calling fire and rescue service.

Clearly I will once given time to charge re-test the chair for the whole run but rather worried about it failing without first any warning lights. The green all well light went out but yellow power light was on it would seem the fault latched some relay to stop the chair being used which is totally unacceptable except at the charging stations.

From what I can see there are safety panels and if the chair hits something it stops the chair I wonder if one of these panels was the real cause for failure but it seems there is no warning light to show when a panel is hit or any instructions on how to re-set.

Has anyone worked with these chairs if so can they shed any light on how they work? Before looking at the chair I thought it was mains operated but it seems all the mains does is charge the batteries it is the batteries which run the chair. Two sealed lead acid mounted on their end which also surprised me.

Mother is an amputee so without chair upstairs is out of the question. There is not the slightest hope if the lift fails that she could return to ground floor.

 

[bernardgreen]

My experience is my mother's stair lift which was mains operated with a cable to the chair.

The switches on the chair that detected obstructions were very sensitive, too sensitive in my opinion but they ""had to operate before the chair pushed a small child down the stairs"". Lack of any indication as to which switch was open did make fault finding difficult.

It had a hinged track end which also had an excessively sensitive switch and that would stop the chair mid flight if someone tried to lift it.

How do the call buttons ( at top and bottom of the stairs ) connect to the chair ? Are there any control cables to the chair or are the call button wireless linked to the chair ?

On the matter of wireless and given the poor reliability of this chair does your mum have any way of raising the alarm if the chair stops in mid flight ?

 

[ericmark]

Base controls are wireless small pp3 battery work them. I have raised the issue before about the fold up lower leg there are no sensors to stop it crushing anything under it wondered if I has missed a sensor so tried it with cardboard box it crushed the box. That is also 24 volt battery operated not a clue why as clearly also permanently on charge. Since the rail does a full 360° half way down the bottom is not visible from the top and it would have been sensible to have the leg controls at the centre charging station and for the chair to be able to travel to the centre first.

However since mother lives alone very unlikely to cause a problem. My thoughts were if the batteries on the chair were faulty I would swap them with the arm batteries.

My mother should wear a pendent which she can press in an emergency however the main unit is too far away from stairs for the monitoring station to hear my mother so although they may know there is a problem they would not know what the problem was. There has also been a problem that she has forgotten to wear pendent but to be fair she only uses stair lift when I am there so I could raise the alarm.

So in all there are 8 switches.
1) Ignition type switch with key in the arm of chair.
2) On/off switch to disengage brake when winding chair manually.
3) On/off switch on arm of chair.
4) Up/Down with centre off control paddle in chair arm.
5 and 6) Pair of radio control switches at top of stairs one for chair and one for leg.
7 and Pair of radio control switches at bottom of stairs one for chair and one for leg.
9) A FCU at top of stairs supplying charger.
There are three places where you can park the chair. Top, Midway, and bottom on the folding leg however the latter is useless as it blocks the only wheel chair access to the house.

I had at first thought I had failed to park the chair correctly and the batteries had gone flat. Design is

like shown looks very like the new Siena but an older model. I have posted before about this unit as I do not consider it as safe.

In that post is an array of pictures which show how it is fitted.

After getting it going again I think it could have been a poor battery connection or one of the safety switches but it also seems removing both battery and mains power was required to reset which would be impossible with mother in the chair. Front cover slides up so seat needs to be empty and folded to remove. I am sure there is an easier way to re-set I am hoping some one knows how it works so can tell me how to re-set.

With the safety issues and the fact that the official Stenner engineer could not even swap a battery correctly it would seem better if I learnt how it worked so I can get it going again quickly if it fails again.

 

[bernardgreen]

The folding leg on my mothers chair would also crush anything underneath it. It was always left down as it only projected about 2 inches across the kitchen door and was not a trip hazard.

I have to say that based on your experience it sems to me as if Stannah quality seems to have reduced.

 

[ericmark]

It was installed in 2005 after my mother lost her leg. It was however mainly used by my dad until his death and rarely used by mother. The upper floor of the house is used as storage as so little space on the ground floor. So every so often I go up with my mother and she will request items to be moved between the two floors. She has never used it on her own. However although the instructions say "Insert winding handle" I have never found the winding handle and using a 1/4" socket it takes an age when I had a working battery drill with reverse not so bad but only mains drill there now with no reverse so can only take the chair up not down.

It ran without a problem when my dad was alive except for him leaving leg down from time to time which resulted in mother not being able to get to door. Controls were wrong side of leg for her to raise the leg.

But now rarely used we seem to be getting problems.

 

[ericmark]

Wiring Diag 260 Stair Lift

• ericmark
• 20 Jun 2015
• 1

At last found a wiring diagram. Seems three relays control the motor RLY1 and RLY2 change direction and any fault will only show with the direction selected. RLY3 however controls both directions is activated when either the other two are activated and is controlled by the Power Relay Controller.

It seems likely the problem is to do with the RF link with the leg. How I could test the RF link not sure it is something I am not happy about relying on an RF link.

I can see the point of not running being considered as fail safe but in real terms leaving a disabled person with no means of escape could hardly be considered as fail safe. It would be better for the lift to crash into the leg than leaving the disabled person stranded upstairs.

Clearly there is a huge difference to helping some one climb the stairs who could in an emergency still manually climb them to transporting some one who without the lift is completely stranded.

From the diagram it would seem feasible to have a keyed over ride for emergency where radio link has failed. I think it's a case of getting the social services involved as I feel as it stands taking my mother upstairs is maybe something which needs abandoning and we need to consider the upper floor as a no go area. In which case the lift may as well be ripped out giving better access.

 

[bernardgreen]

Unless I am mis-reading the diagram but with the battery isolation switch to OFF the brake is permanently connected to the battery. Hardly "isolation" of the battery and a sure way to discharge the battery when it is supposed to be isolated. Or does applying power to the brake release it to allow for hand winding when the battery is "isolated".

Your concerns about relying on a wireless link are valid. Especially if the frequency is the very convenient licence exempt 433.92 MHz which is used by a myriad of short range low power items... some legal and some illegal.

 

[ericmark]

Yes idea of switch is to stop motor running and to disconnect brake so it can be manually wound back to charging station. It states frequency is 868MHz I think my FT50R will receive there but not transmit so I suppose with the S meter I could test signal strength.

It seems there are 10 LED's which should show what fault has happened had I found these before getting it running again maybe they would have shown where the fault was, however not running again so no idea what caused the failure.

Some info is helpful minimum voltage is 20 below that LED 2 lights and maximum current is 18A above that LED 3 lights. Some are less helpful LED 5 means RMU has tripped still not worked out what the RMU is. I can find a RMU sense switch shown together with slowing sense switch. There are so many options where when using the option a link is removed and a poor connection would stop the chair.

 

[Jackrae]

My reading of the circuit diagram suggests what appears to be a short circuit route from the battery positive pole to the negative pole via the second-from-the-left vertical circuit leg.

 

[bernardgreen]

The diode at the bottom seems to be an LED for power on. Not good practise to use the same symbol for diodes and LEDs

 

[ericmark]

The diagram is better than nothing but it is still a problem in that one has no idea what stopped it. The panel is to the right when facing the chair and to the right is the bedroom wall so near impossible to see the array of LED's which it seems should show the fault.

 

[ericmark]

My reading of the circuit diagram suggests what appears to be a short circuit route from the battery positive pole to the negative pole via the second-from-the-left vertical circuit leg.

Thanks. May not been what you intended, but pointing out the two LED's is a real help. When it failed no green LED when running there was so two switches the Ultimate limit switch and the Safety Gear Switch seem to control that green LED.

So what I think happened is the Safety Gear Switch stopped it. Then I manually took to back to charging station and in doing that I activated the Ultimate limit switch so on switching the battery isolator switch back on it still did not work.

So now I need to work out what is the Safety Gear Switch and how did my running down the track activate it.

No Green LED

• ericmark
• 22 Jun 2015

This it would seem is the only bit I am now interested in.

However on returning to my mothers I found it went to bottom of stairs without any real problem but getting it back up was another thing.

IMGP4529_c

• ericmark
• 23 Jun 2015
• 1

There is a line of LED's on the main board to show the fault normally hard to see. But with cover off it proved to be the battery at fault. I would get a few inches at a time and each time it failed the warning beeper to say parked off charging station would sound. Most times it would require the isolator switching off and on to restart but as the distance decreased then just releasing and re-pressing the up button was enough.

Fact it travelled further on the flat rail than inclined does point to battery failure. (Voltage below 20 volt) First battery fitted 03/04/07 which was changed 03/03/11 we assumed failed because not parked on charging station. Second set which have now failed were defiantly on charge and show 27.4 volt until loaded but first set seemed to have lasted 4 years and second set have lasted 4 years so it would seem the batteries have a 4 year live span.

 

[JohnW2]

The diode at the bottom seems to be an LED for power on. Not good practise to use the same symbol for diodes and LEDs

If one looks carefully, it is a standard LED symbol - but, what is naughty is that it is a symbol for a 'bare' LED. The series resistor (without which there would certainly be some 'fireworks') is not shown.

Kind Regards' John

 

[ericmark]

Yes it seems the so called circuit diagram is more like a block diagram missing out fine details. I still feel 4 years battery life is a bit on the short side. Since same batteries are fitted to leg I could try swapping them but more inclined to let social services sort it out.

My main worry was the lift failing while my mother is using it. But since it would only travel inches and clearly will go down easier then up that is not really an issue. It would mean the extending leg would block exit but if used on a regular basis clearly it would fail loaded up well before it failed light up so one would be able to park it.

But since only used about one a month it simply worked one time and completely failed the next about 3 months between known to work and failed.

 

[bernardgreen]

I wonder if there is a log of activity and faults maintained that Stannah could read from the PCB. Probably not as there doesn't appear to be any socket that could be used for testing / reading the chip ( one assumes it is a processor of some sort and not jsut a logica array ).

I am told that Stannah still produce stair lifts with cable to the chair. If that is the case then one wonders why this un-reliable battery in chair system is ever installed.