How to use Radiator thermostats

Taxidriver108

Hi
I live in a 1 bedroom Housing association bungalow with a gas fired combi boiler, 6 radiators all thermostatic valves & a main thermostat in the hall.  We are petrified of the high winter bills we face and have taken the decision to only heat the living room.  My question is:- since the main heating thermostat/timer is in the hall, if we switch all the radiators OFF except for living room the combi boiler will keep heating because the hall will never get hot. When the living room finally gets to temp the radiator will switch off, but the cobi will try to circulate hot water.  This sounds dangerous. any thoughts welcome.

armistice

The main thermostat should be in the coldest (last space/room) to warm up. 
The radiator in that space shouldn't have a thermostatic valve.    
the purpose of the thermostatic valves is to turn off the radiators in spaces/rooms that get up to temperature quicker therefore saving energy rather than overheating rooms.

Your correct, with your question.  Its not inherently dangerous (the combi will maintain a constant temperature in the flow of heating water), but you would be wasting energy with the combi running with no actual demand.

If you have a thermostatic valve on the hall radiator, I would set it at max and adjust the main thermostat to as low as possible while keeping the living room comfortable.

** added as an alternative
The alternative would be to have the thermostat/controller changed a wireless one, which you could then have in the living room. 

tacpot12

You are right to ask the question, but there isn't any danger, other than of slightly higher heating bills. 

You are correct that if the radiator in the hall has a Thermostatic Radiator Valve (TRV), and this valve is turned down too low, the hallway will never get up to temperature and the boiler will think there is always a heat demand and keep running. However, all boilers have a means to detect when this occurs. Old boilers have an overheat thermostat that would kick into stop the boiler firing for a while, and modern boilers have an overheat thermostat AND they are modulating, which means that they sense the temperature of the returning water, and reduce the amount of gas that the boiler burns to maintain the setpoint for the water leaving the boiler. It knows that if the water is returning at 65 degrees and the boiler is set for a flow of 70 degrees it only needs enough gas to raise the temperature 5 degrees. All modulating boilers have a limit as to how much they can turn themselves down by, so if it can't turn itself down low enough it will shut itself down. There should be a pump overrun that continues to push the hot water around the system for long enough for any excess heat (anything over 70C) to dissipate. Your system should have an automatic bypass valve fitted or a radiator that doesn't have a TRV. Either of these will allow the pump to push water around the system even if all the TRVs are shut. So there is nothing dangerous.  

So what should you do?

Given that hallways are difficult to keep warm, due to the number of doors off them, and people coming and going through the doors, I would recommend setting the thermostat in the hallway to the temperature you want the lounge to be at, and set the TRVs in the hall and lounge to this temperature as well - TRVs are pretty inaccurate, so do't expect close control. TRVs are really there to stop rooms getting too hot.

If the hallway does get up to temperature quickly, e.g. if no-one has sed the hallway for a while it will get up to the setpoint of the Wall Thermostat and shut down the boiler. The lounge should be up to temperature as no one has been coming and going through the hallway. 

If the hallway takes a while to get up to temperature, due to people coming and going, the heat will be lost to other rooms in the house, which is no bad thing. You don't want any pipes freezing. Most TRVs have a Anti-Frost setting on them, marked with a Star. In rooms you are not using, I would recommend setting the TRVs to this Star setting to avoid any problems.

With the TRVs set this way, you will be heating the hallway, but given that the wall thermostat is in there, there's no real way to avoid doing so. Turning the wall thermstat down is just going to turn the heating off and the lounge will never get warm enough. At least if you heat the lounge and the hallway, all the other rooms get a little bit of heat from the hallway. 

 

Coffeekup

If the thermostat never gets up to the temperature required the boiler will keep on using kWh's till it gets to the temperature it's set at, bad for environment and bad for you wallet, it will also make the room you are in uncomfortably hot. 

To reduce this you need to move the thermostat into a warmer space or the room where you spend most of your time, or if you cannot move the thermostat warm the space around it. If it can't get get to the temp you require in a cold and draughty hall, best thing to do is turn on and off the heating manually, as long as you remember to turn it off you'll save on your usage and money.

If you did heat one room you'll only go and loose all that heat, soon as someone, leaves the room, goes to answer the door, goes to the bathroom or to the kitchen to make a drink.

When you come home and the home is cold you turn on the boiler, this is going to burn the same amount of kWh's to heat one radiator or 6 radiator's till the room/s get up to temperature where the thermostat is.

So if it was me I would have the living room, bedroom, hall, bathroom and kitchen on warmer setting's and the 6th rad(second bedroom?) On a low setting to keep damp and chills out.

Knowing what I know now about combi boilers and how much energy they use, I would have them on the least amount of time possible.
Example last winter I never got round to putting mine on till last week November or first of December (can't remember which), when I did it was only for 1-2 hours to take the chill off the air, the rest of the time I was under a blanket on the sofa watching TV.
I never heated the house in the mornings when we got up unless it was a day when we were at home, as I thought it was pointless having the heating on for an hour only to be awake and in the house for 30 minutes. kWh's used in that hour of potential heating would have been 21 kWh's. If you multiply that by October's price cap of 15p, it's gonna cost £3.15 which is chunk of money which can be used at a better of the day for you and you're partner or guest to enjoy.
Also my heating hasn't been on since the first week of March.

BUFF

Coffeekup said:

If the thermostat never gets up to the temperature required the boiler will keep on using kWh's till it gets to the temperature it's set at, bad for environment and bad for you wallet, it will also make the room you are in uncomfortably hot. 

To reduce this you need to move the thermostat into a warmer space or the room where you spend most of your time, or if you cannot move the thermostat warm the space around it. If it can't get get to the temp you require in a cold and draughty hall, best thing to do is turn on and off the heating manually, as long as you remember to turn it off you'll save on your usage and money.

If you did heat one room you'll only go and loose all that heat, soon as someone, leaves the room, goes to answer the door, goes to the bathroom or to the kitchen to make a drink.

When you come home and the home is cold you turn on the boiler, this is going to burn the same amount of kWh's to heat one radiator or 6 radiator's till the room/s get up to temperature where the thermostat is.

So if it was me I would have the living room, bedroom, hall, bathroom and kitchen on warmer setting's and the 6th rad(second bedroom?) On a low setting to keep damp and chills out.

Knowing what I know now about combi boilers and how much energy they use, I would have them on the least amount of time possible.
Example last winter I never got round to putting mine on till last week November or first of December (can't remember which), when I did it was only for 1-2 hours to take the chill off the air, the rest of the time I was under a blanket on the sofa watching TV.
I never heated the house in the mornings when we got up unless it was a day when we were at home, as I thought it was pointless having the heating on for an hour only to be awake and in the house for 30 minutes. kWh's used in that hour of potential heating would have been 21 kWh's. If you multiply that by October's price cap of 15p, it's gonna cost £3.15 which is chunk of money which can be used at a better of the day for you and you're partner or guest to enjoy.
Also my heating hasn't been on since the first week of March.

Unless he has a TRV on the radiator in the room that he is in in which case that will shut off that radiator supply at the set temp. so it won't be uncomfortably hot.

In my case my room 'stat is in the coldest room in the house but it is possible to work with that if you know your house/heating system. From years of use I know the offset e.g. if it is 14.5C at the room 'stat it will be 16C in my most used room.

The best way to run your heating varies by how people occupy their house e.g. are they up & out quickly, do they get back early/late or are they in all day. Similarly, going hand-in-hand & of particular note for those with condensing boilers (or heat pumps), take into account whether to run low flow temp & longer or high temp & shorter according.