Yale Wireless HSA6400 Random door contacts not working

Hiya,
I set the alarm (Home) and all devices (DC) are set to go off in Home mode if door/windows open.
I forgot I'd set the alarm and later when burning toast I opened kitchen window. Only realised later that the alarm hadn't gone off and should have! Tested front door/garage door/front window and all working fine. Checking back door/kitchen window - these don't work.
My husband is away and so I'm now really nervous going to bed knowing only half the house is alarmed.
Please can anyone help me to solve this - I'm not the greatest so please be gentle with me.

Many thanks

most likely cause is flat batteries in the sensors.

there is also a faint chance that either the sensors or the panel are close to an electric or electronic thing that is blocking the signal. Most common is an internet wireless router, but I also once had it with a scaffold tower in the stairwell.

I have heard it might happen in a large stone house if the sensor is a long way from the panel, but I have used them in an unusually large Edwardian house with no difficulty.

Observe if the little red light comes on (1) when you open the door (2) when you press the test button on the sensor.

Okay, thanks for your help.
I've put new batteries in and the back door is now working fine.
The kitchen window is still a problem though. It wasn't working at all with a new battery in it's original place (weird). I set the advanced settings to 'door chime' to test and took the contact (DC) off the window and moved it around testing around the window for the best response from the control panel. I replaced the DC where I got a reaction from the control panel.
Then I set the alarm but had to open the window six times before the control panel picked it up and started the countdown. Great for catching 1/6 burglars!

Could it be the contact unit or is it a problem with the wireless connection or any more suggestions?
Many thanks

Does it work in that position when you press the Test button? If you put another sensor in that position does it work? How close is the magnet to the mark on the sensor?

Does the red light come on?

Avoid Duracell batteries as they do not fit well.

If there is any trace of corrosion or dirt on the contacts in the sensor or on the battery, clean them to bright with a stiff nylon toothbrush and just a trace of WD40. It is good practice to do that each time the battery is changed.

Is there a PIR (movement) sensor in the same room?

Well, after a day of trials and tribulations, I finally got the back window to work by finding the one small place I could get a consistent contact response.
So, happily I thought all was fine...tested the house and the back door has stopped working again! What is it with these things!? One minute they work, the next they don't? - so temperamental.
After fiddling for another disappointing hour with the back door, I dropped the contact and broke the battery housing. So, gotta buy a new one. At least the back door locks unlike the back window.
Feeling very frustrated now but hoping the new one will work. Other than that, I'll just have to see if I can put the PIR (we have a spare one) to work in that room instead as it's not in the normal 'run' of the house. Who knows!

Thanks very much for your help. I think we're just working with a weird house here.

Elfsinger said:

Well, after a day of trials and tribulations, I finally got the back window to work by finding the one small place I could get a consistent contact response.

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If there is only one small place from where the sensor's transmissions can be received by the panel then the system is working on the limits of the wireless range. It will not be reliable,

The working range ( maximum distance between sensor and panel ) depends on many factors such as any walls the signal has to pass through, even a person standing in the way will reduce the range.

As JohnD mentioned some electronic equipment creates electrical "noise" which the wireless receiver in the panel will "hear" When there is electrical "noise" the signals from sensors have to be "louder" than the noise in order that the panel can "hear" them clearly enough to be able to understand the message from the sensor.

Other equipment such as Home Automation, wireless thermostats and many other legal to use equipment operate on the same radio frequency as your alarm and the signals from these can prevent the panel hearing its sensors. Have you or a near neighbour recently installed a wireless system of any sort ?

There is also equipment that is illegal to use ( in the UK ) but easy to buy on the internet that seriously interrupts the wireless communications of legal to use systems.

Are you certain the sensors were working before hand. ? It is possible to set some wireless alarm systems even though one or more sensors are totally dead. The panel has no way of checking the sensors are still in the building and working when the alarm is set.

Elfsinger said:

Thanks very much for your help. I think we're just working with a weird house here.

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It is not a weird house, it is a wireless alarm demonstrating the limitations that affect all wireless systems that use one way communications on a Licence Exempt radio frequency used by many other types of equipment. The system is also constrained by the need to reduce use of battery power to the minimum to prolong battery life.

I just don't think this system likes walls at all. The problems I am having are with all the ones in the two extensions. Now the one that was working yesterday into the garage (at the opposite end of the extension with the back door) is not working today. So I've put a PIR in there as well which works (ish) so long as the door isn't closed.
The kitchen is also an extension (not more than 14m from the control panel but still far enough it seems) and that was yesterday's issue.
I'm beginning to think a wired system might have been a better bet.
I don't have any illegal stuff in the house so it isn't that. But as you say, many other legal things could get in the way.
Between the garage/back door extension and the control panel is an outside wall and a stairwell. As you say, that must have seriously limited the wireless information getting through. What I can't understand is why it works one day and not the next. Seems odd to me. If it works...it should just work? Well, obviously it doesn't. Thanks for all your help - just have to start saving and do the job properly and wired instead of going for the 'cheaper' (still £350 kit!) option.

you haven't answered about the red light.

You could try lifting the control panel off the wall and try a different, or more central, location.

the two cases I have heard of where there was much trouble with a signal getting through, one was close to a radio transmitter aerial, and one was close to an arc-welding workshop.

Is there a wireless router (WiFi) or baby alarm?

Sorry, yes, the red lights all work beautifully. Everything works within itself - all the door contacts are working but things just don't seem to be connecting with the control panel - or at least, they do some days and not others. There is a wifi box about a meter away but the door (window in this case) contact on the other side is fine (between the control panel and the window)- the wifi isn't between the problem rooms and the control panel - but maybe that is affecting in a circular manner?
When I'm home again, I could turn it off and see if we have any more luck. Good idea at least to try

I really appreciate all your help and answers.

turn off the wifi and see if that helps. If it does, reposition it.

Surely the receivers in the Yale alarm aren't bad enough that a 2.4 or 5.8GHz wireless transmission is going to interfere with their 433MHz communications?

cybergibbons said:

Surely the receivers in the Yale alarm aren't bad enough that a 2.4 or 5.8GHz wireless transmission is going to interfere with their 433MHz communications?

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Yale User Manual said:

Radio system 433.92MHz AM Integral transmitter and super heterodyne receiver with jamming detection

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The side bands created by digital modulation of a GHz carrier will include energy that would swamp the front end of a near by AM ( amplitude modulation ) receiver. A good AM receiver would have a front end filter that would reduce the problem by requiring more out of band RF energy to swamp the receiver.