is my new room stat working correctly

[ugjointer]

Hi.I have just had a room stat connected to my central heating.The boiler is a worcester28SiII combi and it runs 6 small rads,4 of them have trv valves.The stat is a Newlec.and is positioned in my hallway which has no rad in it.I have opened all the trv's fully and set the stat to 30.c.The stat will fire the boiler up and the heating system does warm up ok but when it reaches the required temp the boiler shuts down all the rads go cold but the stat does'nt fire up the boiler again.I have waited for half an hour or more for the stat to fire the boiler but have to manually turn the stat up to get the boiler to fire.The temp in the hallway is about 20.c.Is 30.c about right for the setting on the stat or should it be higher,could the stat have been wired up wrongly.

 

[transam]

it is possible that , the stat is a 3 wire stat that has only been wired up with 2 wires , e,g live in & live out back to boiler ??? if its a 3 wire stat it should have a neutral , which works as a preheater or anticipator , worth a look ? generally there would be a heat source e.g rad in the area of r.stat ?

 

[D_Hailsham]

The stat is a Newlec.and is positioned in my hallway which has no rad in it.

Can you provide the stat model number?

So the hall is warmed up indirectly from the heat leaving all the rooms?
Why is there no radiator in the hall?
Who decided to put the stat in the hall? It might have been better in the living room.

You should not need to set the stat to 30 to get the house up to 20. The stat should be set to the temperature you want.

 

[ugjointer]

Hi,the stat is a Newlec NLRT room stat.The hallway is very small probably 8ft long with living ,bathroom,kitchen and bedroom doors leading off it.The rad in the bathroom did not have a trv on it and this kept the hallway reasonably warm,The electrician said it would be okay in the hall next to the programmer.Do you think it should be in the living room or one of my other rooms.Regards.

 

[D_Hailsham]

Hi,the stat is a Newlec NLRT room stat.

This stat needs three wires connected. Can you check this?

The hallway is very small probably 8ft long with living, bathroom, kitchen and bedroom doors leading off it.

Ah! A flat!!

The rad in the bathroom did not have a trv on it and this kept the hallway reasonably warm

Are you saying it now has a TRV?
Are you still relying on the bathroom rad to warm the hall?
If so, it should not have been fitted with a TRV. The reason for this is that whichever is set to the lowest temperature will take control. So if you have the bathroom TRV set to 20C and the room stat set to 30C the room stat will never reach 30C as the bathroom TRV will hold the temperature at 20C.

Try setting the bathroom TRV to max. You should find that the hall temperature will rise until it reaches the hall thermostat temperature.

Do you think it should be in the living room or one of my other rooms.

Provided you leave the bathroom TRV on max, you should be able to leave it in the hall. If not, which other room has a radiator without a TRV?

 

[ugjointer]

The bathroom rad does not have a trv .The property is a smallish bungalow.The stat does have three wires.All other rads have trv and are set fully open.As stated before heating does warm up but when it reaches temp and shuts the boiler down it does not fire the boiler up again when the temp goes down.

 

[D_Hailsham]

The bathroom rad does not have a trv.

That's good

The property is a smallish bungalow.

Of course, didn't think of that option for everything on the same floor.

The stat does have three wires.All other rads have trv and are set fully open.

Why install TRVs and then set them fully open? The will not be doing anything if you do that.

As stated before heating does warm up but when it reaches temp and shuts the boiler down it does not fire the boiler up again when the temp goes down.

Will the boiler come back on if you turn the room thermostat to a lower temperature?

 

[ugjointer]

I read someware on the forum that if you have a room stat and trv's on your rads that for the stat to operate correctly the trv's should be turned on fully because of conflict with the stat.When the boiler reaches the temp of the stat it turns off but does not turn itself on again when the temp drops.If I manually then turn the stat up a few degrees the boiloer fires up and heats the rads up again.Boiler will not come back on if stat is turned down

 

[Happyplumber]

Just change the stat to decent one from honeywell,which will work perfectly with your boiler

certain stats are not suitable for combination boilers but Honeywell dont have a problem with any kit.

 

[D_Hailsham]

I read somewhere on the forum that if you have a room stat and trv's on your rads that for the stat to operate correctly the trv's should be turned on fully because of conflict with the stat.

This is only true if the room thermostat is in the same room as a rad with a TRV fitted. If the stat is set to 22°C and the TRV to 20°C, the temperature will rise to 20° and the TRV will kick in to maintain that temperature; it will never rise to 22°C so the boiler will keep running because the room stat can never reach 22°C. If the TRV is set to a higher temperature than the room stat, then the room stat will turn the boiler off before the TRV can operate.

If you don't want to go to the bother of replacing the TRV, then setting it to Max is virtually the same as having no TRV - provided you don't want your house at 30°C.

TRVs in other rooms should be set to the appropriate setting for the room.

When the boiler reaches the temp of the stat it turns off but does not turn itself on again when the temp drops.If I manually then turn the stat up a few degrees the boiloer fires up and heats the rads up again.Boiler will not come back on if stat is turned down

I think the stat may be wrongly wired. I am not familiar with the NLRT so I don't know the appropriate terminal numbers. There are three which are important: Live, switched live (or Load) and Neutral. Can you identify these? If so, swap the live with the switched live. Then report what effect it has.

 

[kittedup]

The electrician said it would be okay in the hall next to the programmer.

Here is where your problem lies.

Most sparkys have no idea about CH wiring.

Ted

 

[ugjointer]

many thanks for all your replies,will get the sparks back to see what he can sort out,could be wired wrongly as as been suggested,something definately wrong someware.regards ugj

 

[D_Hailsham]

The electrician said it would be okay in the hall next to the programmer.

Here is where your problem lies.

What is wrong with having the thermostat next to the programmer?

 

[ugjointer]

The electrician said it would be okay in the hall next to the programmer.

Here is where your problem lies.

What is wrong with having the thermostat next to the programmer?[/qu ote]

Mr Hailsham,I've turned all the trv's to setting 3.The bathroom rad does not have a trv and the bathroom is near to the stat in the hall.The hallway temp is usally round about 20.c.If I set the stat to 25.c the boiler runs and all the rads warm up but when the temp is reached the boiler shuts down but will not fire up again when the temp drops.I am presuming that setting 3 on my trv is hotter than 25c so will not interfere with the stat setting.Inyour opinion do you think the stat is wired incorrectly

 

[D_Hailsham]

Mr Hailsham,I've turned all the trv's to setting 3.The bathroom rad does not have a trv and the bathroom is near to the stat in the hall.The hallway temp is usually round about 20.c. If I set the stat to 25.c the boiler runs and all the rads warm up but when the temp is reached the boiler shuts down but will not fire up again when the temp drops. I am presuming that setting 3 on my trv is hotter than 25c so will not interfere with the stat setting.In your opinion do you think the stat is wired incorrectly

Do you have a separate thermometer so you can check the actual temperature next to the thermostat?

A TRV setting of 3 is usually about 18/19C, so this should not have any effect. In any case it will be the temperature in the bathroom which is important as this rad does not have a TRV. This room will start to cool down as soon as the boiler turns off, so the boiler will start up again when the bathroom has cooled sufficiently. What happens if you open the bathroom window so the room cools down faster?

I still think the thermostat has been wired back to front. There is a small resistor in the stat (called an anticipator), which is supposed to heat up only when the boiler is running. If the Live and Switched Live connections are reversed, this resistor heats up all the time, so the temperature inside the thermostat remains constant. This could explain why your stat never turns the boiler back on and why you have to set the stat to 25 to achieve a temperature of 20.