Central Heating not coming back on after reachng thermostat setting.

[4romseyavenue]

Hi all

my first post and my knowledge of CH systems is very poor.

When the thermostat is set at say 18C in the morning the and the timer is set, the boiler fires up perfectly and reaches the desired setting then shuts off, but it does not seem to fire up again when the temperature drops below 18C again. If I then turn up the thermostat it fires up.

Any reason?

I have bought a new thermostat and it is still the same.

 

[lolipop]

wiring on stat wrong way round

 

[Alpha man]

What make roomstat is it and how many wires are to the roomstat?

 

[4romseyavenue]

Hi

it is a Sunvic with 2 wires

Regards Bill

 

[Alpha man]

Hi Bill, im not sure on specific model, but on all Honeywell roomstats, you need 4 core wire to it and deffo a neutral!

 

[ferret]

where is the stat located , how far below 18 does it get before you turn it up and do you have a thermometer next to the stat to check it with.?? I ask this as location is very important to a room stat , just because you have it set at 18 does not mean it is 18 everywhere ,

 

[4romseyavenue]

Hi I will try reversing the wiring at the weekend.

The boiler seems to still heat up after the temp has been reached. When I turn it down it goes off, and eventually when it gets cold and you would expect the heating to start again, it does not. When I turn up the thermostat manually to the point where it clicks, the heating comes on again. Perhaps it is the wiring.

Thanks Bill

 

[ferret]

the wiring sounds ok as it is doing as expected , i think its just your understanding the stat , try this ...turn the stat up to maximum and sit in the lounge watching tv or whatever , then when you feel that the temp is how you want it , go to the stat and turn it down slowly till it clicks them back up 1/2 a degree this is then the set temperature for you ,and you should leave it alone it will come on and go off +- 2deg , take no notice of the stat temp except as a reference for your comfort .

 

[Bartdude]

If the thermostat has a bi-metallic sensing element it won't respond as quick as an electronic one. You could change it if it's a problem,but as ferret says,is your house warm enough,or are you just noticing that the heating isn't on. If you're not cold,it's working properly.