RF linked thermostats.

[ericmark]

I set up mothers house when just her in the house with one thermostat for the day and one at night, so living room was spot on in the day, other rooms using TRV and lock shield valves to be some where near what was required. And a night the bedroom thermostat kicked in so that room spot on and again other rooms just some where near.

I had problems with mother moving the thermostat out of range, so although the living room one could be portable I screwed it to the wall. When it was mobile I found major fault, it did not hand shake, so if it tried to switch on central heating and for some reason it failed to go into run mode, even if that reason was corrected it would not switch on the central heating unless I set it low then high again. Same in reverse, if it looses signal then will not turn central heating off, even when what every caused it to loose signal was corrected.

The Honeywell Y6630D wireless room thermostat worked A1, however the Horstmann HRFS1 programmable thermostat was causing a problem, as to if this was due to swapping temperatures for different times of day, its location, or interference hard to tell. But since screwing to the wall the Horstmann seemed to be doing as it should do.

Then one week ago it all started again. Hunted for cause, however there is nothing to show signal strength so how does one know if on the edge of range or well in range. So step one change batteries, not something one wants to do as it all needs programming again. Still playing up, swapped frequency, still playing up, so swapped a second time, still seemed to be playing up, moved 12 inches to left and a little lower on wall selected so no kitchen cupboards between sender and receiver and it is all working again.

I tried to reposition cordless phone, and the call centre receiver it did nothing to improve things, also moved mobile phone well away from area. At the moment I am not transmitting so not my amateur gear. The TV with wireless connection to router had not moved, the router had not moved, detached house.

Although all working again, I worry about it failing, both my mother and I are very susceptible to temperature changes, I have a mauled hand and if it gets cold I am in a lot of pain. The Honeywell is much further away than the Horstmann but had no problems with Honeywell. In my own house thermostat is hard wired, I use a Horstmann without any problems except for the odd flat battery.

So am I unlucky in mother house? or are Horstmann RF thermostats low in output or something? Is there any way to measure signal strength? If it had failed to work on and off many times I would just say interference, but it ran for 3 months then failed, has any one else had these problems?

 

[bernardgreen]

Eric

Does the boiler have a variable speed fan ? If it does then when the fan is running it creates radio frequency energy with a significant field strength close to the boiler. This will reduce the receiver's ability to "hear" the transmitter if the receiver is close to he boiler.

Some thermostats only send a START command to start the boiler an STOP command to stop it. The START command will be received as there us no RF energey from the fan. The STOP command will have to compete with the RF field from the fan that is now running.

Some systems use a START command which turn the boiler on for a preset time period. After that timed period the boiler will shut down unless in the mean time the thermostat has sent another START or a KEEP RUNNING. This time out ensures that the boiler will not run indefinately if communication with the thermostat is lost and the boiler cannot receive the STOP command.

 

[ericmark]

Eric

Does the boiler have a variable speed fan ? If it does then when the fan is running it creates radio frequency energy with a significant field strength close to the boiler. This will reduce the receiver's ability to "hear" the transmitter if the receiver is close to he boiler.

I think this is unlikely as the receiver is about 6 foot from boiler.

Some thermostats only send a START command to start the boiler an STOP command to stop it. The START command will be received as there us no RF energey from the fan. The STOP command will have to compete with the RF field from the fan that is now running.

Since I have problems both starting and stopping it seems this is not the problem.

Some systems use a START command which turn the boiler on for a preset time period. After that timed period the boiler will shut down unless in the mean time the thermostat has sent another START or a KEEP RUNNING. This time out ensures that the boiler will not run indefinitely if communication with the thermostat is lost and the boiler cannot receive the STOP command.

Now this is interesting, and it would at least stop the over heating part of the problem, however would not cure the problem of heat not coming on. I have wondered if the signal is sent at set intervals, I have found the heating has not come on when changing temperature, done some other task then returned to find it running.

It says "to adjust the address code of the receiver" and continues, however an address code could be frequency, but it could also be a code sent to identify its self. It has a section in the manual about "Testing the RF transmission" however all it says is alter temperature and see if it works. It says with multi-receivers they should be 1 meter apart, however I have just the time clock and kitchen consumer unit between them so only about 18" apart, but they are different makes.

The house is quite good, so on a timed change in temperature at 9 am by mid-day the house has not cooled down enough for the heating to cut in again. There are 4 dip switches the first 2 set the span 0.5°C to 2°C I have it set to 0.5°C. The remaining 2 are for heating or cooling and block of 5 and block of 2 days, or 7 individual days, it's set to 7 individual days, one of the reasons for selecting, heating turned down on Wed and Sat when mother goes to day care.

I looked at Flomasta 2260SX wireless but has not got 7 day mode, there is the Danfoss TP7001, but could have same problem, the iQE 1 channel Z wave 7 day time control RF thermostat does look good, never tried Z wave, it has an indicator to show RF link is running, however it is like the Honeywell Y6630D wireless room thermostat in that it only has one temperature setting it's either on or off it does not change setting during the day. So in real terms unless I went for a really expensive system like EvoHome the Danfoss TP7001 is the only other thermostat which will do what I want.

I need a new thermostat at home, the battery leaked so will need changing, so buying new and swapping is on the cards. But still monitoring the Horstmann HRFS1 programmable thermostat to see if there are any more problems after changing channel.