Honeywell CM291 wireless range

[timtheenchanter]

Since installation, I have had numerous problems with the thermostat on our CH system.

it usually clicks the boiler in, but after a couple of mins it clicks it off again (even though the transmitter is showing boiler on, the relay box is turning itself off)

each time it starts to do this, I have been "advised" to re-bind, after which it usually works for a couple of weeks, this time I have tried to re-bind, twice and replaced the batteries (with procell, not cheapies)

Ive not found the spec on the range of this unit.

in a straight line from the unit to the receiver are 2 solid brick walls, and with it being mounted on the end of a wall, about another 4 feet of solid brick, and a wooden staircase.

now, I do some work in theatre, and radiomics are a similar frequency to these (868-868.6MHz from the info I have found) and I would expect little if no transmission thorough that amount of blockwork from a 30mW transmitter, so in my mind, the large proportion of the problems lie here, can anyone confim this before I start to get cross with the installers.

 

[D_Hailsham]

Ive not found the spec on the range of this unit.

They say 30 metres in open air.

in a straight line from the unit to the receiver are 2 solid brick walls, and with it being mounted on the end of a wall, about another 4 feet of solid brick, and a wooden staircase.

That's a lot of attenuation.

so in my mind, the large proportion of the problems lie here, can anyone confim this before I start to get cross with the installers.

The installers should have checked the signal before fixing the receiver in place. This is easy to do - you just attach a long lead with a 3 pin plug on the other end. The receiver can then be moved about until you find the best position.

 

[mikely]

It is normal for the heating to be off some of the time even though the thermostat is demanding heat (flame symbol ON). Quoting from the user guide:

Symptom: The thermostat’s LCD display shows a (flame) symbol but the heating does not switch on.

Remedy: The heat demand is sent to the BDR91 as a value between 0-100%. The BDR91 will adjust the boiler on time to meet this requirement. That is why the heating will be off sometimes even if the (flame) symbol is displayed. To check if RF system is communicating properly press the button to increase the set temperature a few degrees above the current temperature. The heating should come on after a few seconds.

Have you tried moving the thermostat closer to the receiver to see if it operates any differently? If the green LED on the relay box is lit, this indicates that the RF communication is OK.

 

[timtheenchanter]

it comes on if I increase the temp, but only stay on for between 30 secs and 5 mins, no matter how high I put the temp on the thermostat.

example, since I got home I programmed the heating to come on in 10 mins, at 30 degrees. It came on, stayed on for 2 mins, then went off.
the green LED comes on to kick the boiler in, but goes off after 2 mins to turn it off again (when it shouldn't).

the thermostat registered the room temp as 17 degrees, and the flame symbol lit up.
I left it like this for 2 hours, the boiler did not come back on.

the only way I have managed to get it to work recently is by having the thermostat in the pantry so it is about 2 feet from the receiver, with one brick wall between it and the receiver.

it seems like its doing its own thing, ie listens to the boiler on command, then gives up, the thermostat end doesn't them send subsequent boiler on commands because it thinks the boiler is on.

Incidentally, the installers talked my wife through a re-set and re-bind today, before I tried this out, and it has made no difference.

 

[timtheenchanter]

The installers should have checked the signal before fixing the receiver in place. This is easy to do - you just attach a long lead with a 3 pin plug on the other end. The receiver can then be moved about until you find the best position.

hmm, possibly but the numpty managed to shock himself twice whilst installing it, once, OK, should have been more careful (and turned the power off) but twice!