Center room thermostat EHE0200361 misbehaving

[Ken Dunn]

On a recent cold night I decided to set the overnight temperature from the standard 5deg C to 15 so the boiler would operate in the middle of the night if it went cold. It had been operating set at 20 when we went to bed and shut off as expected. It was coming down in temperature. I was woken at 2-15 with the heating coming on (as expected). The problem was it ran for about 5 mins and shut down. After only 1min it fired up again and continued cycling like this. It did not run long enough to get the bedroom radiator even warm. The heating system is a bit noisy before it settles down on a normal early morning warm up and this cycling could not be tolerated to see if the cycling time extended and gave some heat out to the bathroom and landing radiators. The thermostat seemed to see it as the system had reached the required temperature.
Is this a software issue in the thermostat or is it faulty and needs replacing. It is only 3 months old.
Normally on reaching the setting temperature rising it seems to cycle as if the differential is too low but the heating system is not noisy so I have accepted this.
Views please.

 

[chrisw99]

I have just had a new combi boiler installed, using the same wireless room thermostat, and I'm having trouble figuring out how best to use it.

In the living room, it can be 22C and it keeps the temperature at this nicely. The problem is, if I turn off the heating it stays at 22C for ages, even once it starts to go chilly. I don't think it's the thermostat itself because if I move it into the garage where it's freezing it starts to plunge, but put it back into the living room and it rises back to 21-22 ish.

I deliberately woke up and went downstairs in the middle of the night and it was absolutely freezing everywhere, yet the thermostat was still saying 18.5 in the living room so there's no way it would ever fire the heating to warm the house on a cold night unless I raised the overnight temp to 19.

Why would my living room still be registering as "warm", when it's freezing, yet moving it elsewhere it drops. Is there something else that comes into play with these thermostats e.g. humidity? I've ordered a room thermometer from Amazon so I can put it next to the stat and make sure it is reading correctly. I know you can adjust it +/-3 degrees from the installer menu.

 

[Ken Dunn]

You are right to buy a separate thermometer, I have a weather station with an outside sensor and it reads inside as well. You will then be able to check the calibration of your room stat. My room stat definitely reads the truetemperature. It does take several minutes to adapt to the room temperature. It also picks up heat from your hand if you are holding it.
Humidity affects how you feel so a temperature reading of say 15 Deg will feel colder in a high humidity than in a low humidity at the same temperature. Also windchill affects how you feel in a draught but the thermometer reads the same temperature, inanimate things like thermometers do not sence windchill or humidity only humans do. If that 22 is the correct ambient temperature then you are lucky to have a very good insulated room, I wish I had but with no cavity walls my house looses heat quickly.
I note the + - 3 deg but my installer did not react when I asked him what the differential of the room stat was. I will look into that, thanks Ken.

 

[chrisw99]

Cheers for the tips, need to have a play and find the best place to locate it. Just bought a cheap liquid thermometer from B+Q which seems to be quick and accurate (was reading 20 in the store, dropped to 15 by the time I reached my car. Turned the car climate to 24 and it went to 24...).

Having it in the living room isn't going to be the best if that stays warm overnight and the rest of the house is freezing.

 

[chrisw99]

I had a play last night and I was pleasantly surprised to notice my thermostat *is* reading accurately. Took it into the garage and the liquid thermometer dropped to 9C. It took a good 25-30 minutes for the room thermostat to drop from 22C to 9C but it got there. And I suppose in practice a room is never going to drop in temperature quicker than that so it should always keep up with the real drop.

So the interesting thing now is all the thermometers in the middle of the night are saying about 18C in the house, yet it feels freezing cold to me. Just as cold as inside the garage was at 9C. I guess during the cold snap I'll just set the overnight temp on the stat to 18.5 now that I know that's what it gets to.

 

[Ken Dunn]

Glad you are making progress, you seem like my wife who feels the cold and psychologically needs to feel a radiator on, even if the thermometer is reading a high. Nevertheless it is how you feel then that’s what matters.
It’s far cheaper to get under the duvet, and set your timer to come on half an hour earlier.!,

Yesterday I got a number for technical queries for the Center Thermostat and spoke to a knowledgable women about my problem. It’s a mobile 07795265810.There is an 0870 number on the back of the user guide but is unobtainable. They are located in Bracknell so I suspect it is Honeywell.
The upshot is that it is working as designed.
She did explain about proportional band width and how clever the room Thermostat is. As you use it it builds up a picture of the performance of your system, how quickly it warms your room and how it cools off. With proportional band width set at 1.5 deg when the temperature gets to 1.5 deg to the setting point it starts to reduce the gas used so that it doesn’t used extra gas and reduces the overshoot. My Thermostat is portable and I have been moving it from room to room. Apparently this is not a good thing as it has to learn a different charastistic for the new location, so I am keeping it in one place in the bathroom which is my coldest room.
Also the temperature offset of say + up to 3 degrees means that it will operate as if it is set 3 degrees higher.
Anyway I have wittered on
Cheers
Ken

 

[chrisw99]

Glad you are making progress, you seem like my wife who feels the cold and psychologically needs to feel a radiator on, even if the thermometer is reading a high. Nevertheless it is how you feel then that’s what matters.
It’s far cheaper to get under the duvet, and set your timer to come on half an hour earlier.!,

Yesterday I got a number for technical queries for the Center Thermostat and spoke to a knowledgable women about my problem. It’s a mobile 07795265810.There is an 0870 number on the back of the user guide but is unobtainable. They are located in Bracknell so I suspect it is Honeywell.
The upshot is that it is working as designed.
She did explain about proportional band width and how clever the room Thermostat is. As you use it it builds up a picture of the performance of your system, how quickly it warms your room and how it cools off. With proportional band width set at 1.5 deg when the temperature gets to 1.5 deg to the setting point it starts to reduce the gas used so that it doesn’t used extra gas and reduces the overshoot. My Thermostat is portable and I have been moving it from room to room. Apparently this is not a good thing as it has to learn a different charastistic for the new location, so I am keeping it in one place in the bathroom which is my coldest room.
Also the temperature offset of say + up to 3 degrees means that it will operate as if it is set 3 degrees higher.
Anyway I have wittered on
Cheers
Ken

Don't apologise for wittering, useful information that as I was wondering what the proportional bandwidth meant when I saw it in the setup menu. Defaults to 1.5 and goes up to 3.

There's also a "max number of cycles per hour" which can be 3/6/9/12 and defaults to 6.

I read you should never have the thermostat in the bathroom because all it takes is for someone to run a hot bath or hot shower on a cold day, your bathroom gets warm and it stops heating the rest of the house.

 

[Ken Dunn]

Yes a good point but other considerations mean it’s the optimum location for me. I’ve been keeping my eye on this cycling thing and the pump keeps running for a minute or so evening the temperature of the boiler and pipes. It all contributes to maximum efficiency. Now I understand the system I am pleased with how it’s performing. I used to turn the boiler water temperature down so that the boiler maintained the house background temperature and ran all the time, however with this cycling it achieves the same thing with the benefit of switching the boiler off for periods and running it at a high temperature which is more efficient. It takes account of warm days like today by lengthening the off period and the very cold days like last week with shorter or no off periods. So no more keep altering temps and times. Ken

 

[snb]

Default on these stats ( they are Honeywell cm range) is minimum on time 1min with 6 cycles per hour.
Change it to min on time 5 mins with 3 cycles per hour.

 

[smallplane]

Glad you are making progress, you seem like my wife who feels the cold and psychologically needs to feel a radiator on, even if the thermometer is reading a high. Nevertheless it is how you feel then that’s what matters.
It’s far cheaper to get under the duvet, and set your timer to come on half an hour earlier.!,

Yesterday I got a number for technical queries for the Center Thermostat and spoke to a knowledgable women about my problem. It’s a mobile 07795265810.There is an 0870 number on the back of the user guide but is unobtainable. They are located in Bracknell so I suspect it is Honeywell.
The upshot is that it is working as designed.
She did explain about proportional band width and how clever the room Thermostat is. As you use it it builds up a picture of the performance of your system, how quickly it warms your room and how it cools off. With proportional band width set at 1.5 deg when the temperature gets to 1.5 deg to the setting point it starts to reduce the gas used so that it doesn’t used extra gas and reduces the overshoot. My Thermostat is portable and I have been moving it from room to room. Apparently this is not a good thing as it has to learn a different charastistic for the new location, so I am keeping it in one place in the bathroom which is my coldest room.
Also the temperature offset of say + up to 3 degrees means that it will operate as if it is set 3 degrees higher.
Anyway I have wittered on
Cheers
Ken

#

I have recently moved into a house with this thermostat (and in fact first time with GCH)
I have found your info very useful

I was wondering why the flame light indicator stays on for a bit when the room is up the temp
Plus I've noticed that the radiators aren't as hot to touch when the room is up to temp (with flame light on) as they are when the radiators first come on.
Do you think this will be down to the reduce gas its things the put in you post?
Thanks
Ian

 

[chrisw99]

Default on these stats ( they are Honeywell cm range) is minimum on time 1min with 6 cycles per hour.
Change it to min on time 5 mins with 3 cycles per hour.

What will this achieve? I've had mine since December and it worked very well at the default settings of 1 min / 6 cycles, but I'm always on the lookout for improvements!

 

[snb]

What will this achieve? I've had mine since December and it worked very well at the default settings of 1 min / 6 cycles, but I'm always on the lookout for improvements!

if you have only 1 heating zone and you have less than a dozen or so rads then changing this will do very little if anything for your system. The alterations only help if you have motorised valves and problems with some rads never getting hot due to system not on for long enough

 

[chrisw99]

if you have only 1 heating zone and you have less than a dozen or so rads then changing this will do very little if anything for your system. The alterations only help if you have motorised valves and problems with some rads never getting hot due to system not on for long enough

Just one zone and 9 rads, and they all get hot very quick. I'll leave it on default. Every 10 mins the same cycle repeats. Fires 2-3 mins, pump remains running a further 2 mins, 5 mins off.

 

[heatservice]

Modern boilers modulate meaning they adjust their heat output according to the systems demand, older boilers tended to be all or nothing, the burner indicator light might remain on but you can hear the fan speed slow down as it modulates to low flame. If you have a combi type boiler it can run when there is no demand due to the preheat feature being turned on.