Wireless room stat - temperamental heating

[Mark-B]

Good evening

I'm having problems with our central heating system. I think it's a conventional boiler rather than a combi, with a cold water tank in the loft an a hot water cylinder in the airing cupboard. The problem I have is with the Boss Therm wireless room stat, it doesn't seem to turn the heating on when it is supposed to. Pressing the advance button on the heating progammer has no effect other than to turn on the light on the programmer. The heating doesn't always come on when programmed, it seems to come on when it wants!
I have replaced the batteries in the room stat and tried resyncing the stat and the receiver.
Has anyone got any advice on what I should do next?

Thank you.

 

[D_Hailsham]

Is this a new problem, i.e it worked ok previously?

What happens if you move the thermostat nearer to the receiver (say 1m away)?

 

[Mark-B]

We hadn't noticed a problem with it until the house started to get colder with the weather. The battery symbol was lit so I changed the batteries, after that we noticed the heating wasn't coming on when programmed so I resynced the stat with the receiver following the instructions and it seemed to be working but at the next programmed time the heating failed to come on so it clearly wasn't working.
I have tried moving the stat near to (almost touching) the receiver but there doesn't seem to be a connection.
According to the instructions, pressing the test button on the back of the stat should cause the heating to come on but when I tried that this evening nothing happened. The instructions say "RF Test" should come on in the display and disappear when you press the button again but it's only there for as long as the button is pressed.
I also stood watching the clock on the programmer (only a couple of minutes - I'm not that bored!) when it turned 8:30 the heating lamp came on as expected but there was no life in the receiver and no heating came on. Both lights on the receiver are off. The heating was working fine earlier this evening, it's almost like there's another schedule that I don't know about! The heating comes on later in the evening pretty much every night but I'm not sure what brings it back to life. The heating does work but not all the time and always within the scheduled times.
I just double-checked the programme, I'm not going mad - something isn't quite right.

Mark

 

[D_Hailsham]

If you hold the thermostat too close to the receiver the signal will be too strong.

Is the receiver close to the boiler? It should be at least 450mm away.

Do you have a multimeter - and know how to use it?

If so, check that there is a permanent 240Vac between L and N on the receiver.

 

[Newboy]

Is the room stat programmable?

e.g. Boss Therm 242

If the room stat is programmable then the HTG should be set to continuous on the programmer and the time/temp controlled from the room stat

 

[Mark-B]

Thanks for the quick replies.
The stat is not programmable, it just has a temperature dial and display on it. There are two buttons on the back: test and learn. The model name on the front is BRTRF.
I can see why you would ask that though, it does seem like there's another programme set somewhere.
I just did a quick test while stood in front of the receiver. I turned the temp down below the indicated room temp and the heating turned off, waited a few seconds and turned it back up, heating came back on. That looks to me like it is working perfectly.
The receiver is at least 450mm away from the boiler, the boiler is in the loft and the receiver in the bedroom below.
I do have a meter so I can check voltage, however doesn't the fact the it is working now mean there is power.

Thanks

Mark

 

[Newboy]

What exactly are the symptoms of the heating not working?

 

[D_Hailsham]

It may be working now; but why does it stop working?

Is there a timer built into the boiler? (Which boiler is it - you don't say?)

Please remove the relay from the wall (turn power off first). Then post a list showing which wire is connected to each terminal.

 

[D_Hailsham]

What exactly are the symptoms of the heating not working?

See the first post!!

 

[Newboy]

See the first post!!

That doesn't describe EXACTLY what is or isn't happening.



1) Where is the room stat positioned in the house?

2) With the programmer set to HTG constant, with the room stat in it's usual location, when demand is signalled, does the RF receiver receive the call?

3) When the RF receiver receives the call (assuming the answer to Q2 is ye), does the boiler fire?

Please remove the relay from the wall (turn power off first)

There's no point in starting to take components apart until the basics have been checked first.

 

[Mark-B]

The boiler is a Worcester Greenstar 15i, installed in March 2010. Can't find any reference to a timer in the manual.

Answers to above questions:
1) Where is the room stat positioned in the house? In the hallway, temp in there is usually lower than the rest of the house.

2) With the programmer set to HTG constant, with the room stat in it's usual location, when demand is signalled, does the RF receiver receive the call? No, the receiver does nothing, doesn't even light up. However, it was working as expected earlier this evening. It seems that at certain times of the day it doesnt matter what happens with the stat the heating doesnt come on. It seems to start working again around 10pm, it's set to be on between 8:30pm and 11pm.

3) When the RF receiver receives the call (assuming the answer to Q2 is ye), does the boiler fire? See above...

Thanks,

Mark

 

[Newboy]

No, the receiver does nothing, doesn't even light up

When you tried earlier it worked, was this in it's usual location or nearer to the RF Rec'r?

Unless there is any form of timer on the boiler itself - open the drop down front panel and double check (as unlikely as that would seem!) then that would seem to suggest interference between the stat and rec'r - are you making use of Wi-Fi/routers?

 

[D_Hailsham]

There's no point in starting to take components apart until the basics have been checked first.

Agreed. One of the basics to check first is that the receiver has been correctly wired. The fact that it works sometimes, but not always, would suggest a wiring error.

 

[Newboy]

The fact that it works sometimes, but not always, would suggest a wiring error.

The last thing that an intermittent fault would suggest would be a wiring error.

 

[D_Hailsham]

Is the LED at the top of the receiver Red or Green?

If you press the Override button on the receiver, does the boiler come on?

Which brand batteries are you using?