Boiler and Room Target Temp Never Reached

[fadsarmy]

I let my nephew stay at my house whilst I was away for several days. I set the thermostat temperature to 25 C but my nephew left the window open so the room temperature never reached 25 C and the boiler remained on. Would the boiler work continuously to reach the target temperature or is there some mechanism to prevent overworking the boiler?

 

[Chuck]

I let my nephew stay at my house whilst I was away for several days. I set the thermostat temperature to 25 C but my nephew left the window open so the room temperature never reached 25 C and the boiler remained on. Would the boiler work continuously to reach the target temperature or is there some mechanism to prevent overworking the boiler?

25 is way too high for a healthy adult. Something in the range 18–21°C is more like it.

Your boiler is unlikely to have done anything other than ramped up to maximum in a vain attempt to heat the whole planet to 25°C via your open windows. This is not going to have damaged the boiler but it will, however, have used more gas than normal in September when you would not normally be using much for heating at all.

 

[fadsarmy]

Okay thanks but would the boiler work continuously in an attempt to reach target which it would never achieve?

 

[SJB060685]

When a system is designed it is is designed for max load conditions. This is usually -2 or -3 outside temperature and a target room temperature of 21°c. From the calculations you will determine the heat loss in watts per room.
Now say a room has a window or door left open, this will massively increase the heat loss, so much so it's unlikely that room will ever reach target temperature, even on a mild day. It will also cause what's called micro zoning, whereby Any adjacent rooms will struggle as well.
If the system was designed correctly then the output of the heat source will provide enough power to maintain target temperature at maximum load. If in milder weather the boiler could potentially reach and increased target temperature but leaving windows open will impede that chance.

 

[fadsarmy]

When a system is designed it is is designed for max load conditions. This is usually -2 or -3 outside temperature and a target room temperature of 21°c. From the calculations you will determine the heat loss in watts per room.
Now say a room has a window or door left open, this will massively increase the heat loss, so much so it's unlikely that room will ever reach target temperature, even on a mild day. It will also cause what's called micro zoning, whereby Any adjacent rooms will struggle as well.
If the system was designed correctly then the output of the heat source will provide enough power to maintain target temperature at maximum load. If in milder weather the boiler could potentially reach and increased target temperature but leaving windows open will impede that chance.

I appreciate your detailed response. My main question is whether a boiler runs indefinitely and risks damage if the target temp is never reached?

 

[SJB060685]

In this particular scenario the boiler will run at full output, constantly trying to achieve your target temperature, which in this case you never will
This won't put any more strain more strain on the boiler than in normal situations but will be on constantly.

 

[snowhead]

If the thermostat was in the room with the open window the boiler would probably be running flat out most of the time, depending on the size of the window and amount of heat lost through it.
If it was close to or over 25 outside then there'd be little or no heast loss and the boiler wood switch off.

 

[John.g]

I appreciate your detailed response. My main question is whether a boiler runs indefinitely and risks damage if the target temp is never reached?

The boiler will only run at full output if the heat emitted from the rad(s) is = or greater than the boiler output, if the heating demand is less than the boiler output then the boiler will modulate to maintain its (boiler) target or setpoint temperature which might be about 65C, it will not damage the boiler, only your pocket. The boiler will continue to run like this until the room target temperature is met.