Boiler won't turn off, but nothing is requesting heat.

unwashed potato!

unwashed potato!

unwashed potato!

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We have a baxi 800 gas boiler and Drayton wiser smart system, with their smart TRVs on every radiator.

Even when every radiator is set to off (verified through the app) and the hot water off, the boiler is still firing up and pumping.

The only radiator that gets hot is the one in the bathroom is it's always open, however it doesn't have a trv and no other radiator gets hot because they are all closed and not requesting the boiler to be pumping heat to them.

It's fairly new boiler at 3 years.

Any ideas what could be causing the issue? It's located in the loft. Is there perhaps a safety feature where it runs if the space that the boiler is in is below a certain temperature, so that it doesn't freeze?

The only way to get the boiler to go off and spray off is to switch the power off to it
 
Some of the TRV are low on battery, but I can see them all on the app as showing off, I can boost them, they then turn on etc, so they don't appear to be requesting anything.
 
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Could it be some sort of frost protection? The loft obviously is freezing cold at the moment.

My concern is that it just seems to be on off constantly

. It's not like the boiler fires up for 10 minutes and then is off for an hour. It's on for 5 minutes, off for 5 minutes, on for 5 minutes, and repeat.
 
Frost protection.
Below ~5°C the boiler will run regardless of what the control is asking for... laid in bed at the minute and it's 22.3°C in the house despite asking for 14!
Our boiler is in the garage.
 
NoNameNoNumber said:
Frost protection.
Below ~5°C the boiler will run regardless of what the control is asking for... laid in bed at the minute and it's 22.3°C in the house despite asking for 14!
Our boiler is in the garage.
Click to expand...

But should it not just kick in very lightly to prevent frost issues rather than fully circulate the system? I have a frost stat on mine also set to about 5c but the boiler location never gets down to that really.
 
It's the flow return. Your boiler fires up every so often so that you have instant hot water from the tap. It also costs a lot of money apparently.

Despite the posts above it's not frost protection because mine fired up all the time in summer.

I turned mine off (following advice from Martin Lewis). It doesn't turn on randomly any more but I have to run the kitchen tap for 2- 3 minutes to get hot water and takes about 5+ minutes for the shower to be warm.

Your boiler instruction manual will tell you how to turn it off
 
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rumple9 said:
It's the flow return. Your boiler fires up every so often so that you have instant hot water from the tap. It also costs a lot of money apparently.

Despite the posts above it's not frost protection because mine fired up all the time in summer.

I turned mine off (following advice from Martin Lewis). It doesn't turn on randomly any more but I have to run the kitchen tap for 2- 3 minutes to get hot water and takes about 5+ minutes for the shower to be warm.

Your boiler instruction manual will tell you how to turn it off
Click to expand...
The Baxi 800 doesn't have DHW preheat.

OP, It could well be frost protection, and that depends how that protection feature has been installed. The boiler will have its own (normally 5C, and a loft space will be that cold) or there could be a frost stat installed next to the boiler, but this really should be fitted with a pipe stat to stop the frost protection heating the property.

You would also be wanting to check for a switch live to the boiler from the controls to rule out (or confirm) any issue from your smart controls.
 
If you have a boiler in a cold un heated area an external frost stat (usually at the side of the appliance) will activate the boiler at around 4/5C. The problem is, the boiler will then commence to run the heating (usually) but this will not heat the location of the boiler....So the frost stat keeps the boiler running because it's still cold.
A pipe stat connects in series with the frost stat and connects to the boilers pipework. So when the boiler fires from the frost stat, it (boiler) only needs to get slightly warm before the pipe stat switches the circuit off.

So you get frost protection where you need it without heating the house.

The type and method of frost protection can vary for different types of installations, but that's the most common for an average system.

If a boiler has its own frost protection built in, then it's just a case of making sure the plumbing circuit allows it to function correctly if required.
 
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rumple9 said:
It's the flow return. Your boiler fires up every so often so that you have instant hot water from the tap. It also costs a lot of money apparently
Click to expand...

Definitely not this. We have a hot water tank.

FlyingFish said:
If you have a boiler in a cold un heated area an external frost stat (usually at the side of the appliance) will activate the boiler at around 4/5C. The problem is, the boiler will then commence to run the heating (usually) but this will not heat the location of the boiler....So the frost stat keeps the boiler running because it's still cold.
A pipe stat connects in series with the frost stat and connects to the boilers pipework. So when the boiler fires from the frost stat, it (boiler) only needs to get slightly warm before the pipe stat switches the circuit off.

So you get frost protection where you need it without heating the house.

The type and method of frost protection can vary for different types of installations, but that's the most common for an average system.

If a boiler has its own frost protection built in, then it's just a case of making sure the plumbing circuit allows it to function correctly if required.
Click to expand...

I guess this is likely to be it.

The only radiator that gets heat during the night is the one in the bathroom, due to this one not having a TRV to close it.

If I take the TRVs off any other radiator, they then get hot because they are now open with the TRV removed.

Is it correct that the boiler is then trying too push the heat around whole system? It's just lucky that due to the smart TRVs most rads but one is switched off?

I don't mind the frost protection, but it doesn't make sense to me that it is always on, and not every 30 minutes or so doing a quick boost to itself.
 
Does it have Danfoss port valves? We had the same issues as your describing and it turned out to be one of the 2 port valves that was failing. Changed them both just in case and it cured the issue.
 
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I may be reading this wrong (not very with it:)) but if there is no controlling thermostat then the boiler is likely operating just on a timer which means that during the timer's "on" period the boiler will be running pretty much all the time.

Thermostatic valves on the radiators control the room temperature but unless they can also tell the boiler to shut off, they won't control the boiler running.

We used to have a similar system, where the boiler was controlled purely by a timer and it was useless, upgrading the control to include a thermostat that basically told the boiler to kick in/cut out during the "on" period made a huge difference.
 
Werewolf said:
Thermostatic valves on the radiators control the room temperature but unless they can also tell the boiler to shut off, they won't control the boiler running
Click to expand...
That is what they essentially do

The radiators have their own TRV, which is connected by WiFi, and it knows the rooms temperature.

From within the app, we set a timer that each TRV will come on and off, and to what temperature to get the room to.

So for instance, at 5pm the lounge and 2 bedrooms come on, and those trvs then tell the boiler, I need heat if I'm below x temperature, and so the boiler turns on until it reaches that temperature, or the timer runs out.

It's by far the best system I've seen available, as I'm only heating the rooms I need heated. Our tenant leaves for work at 5.45am, so we heat just her tiny room at 4.30am for 40 minutes, where as in a normal setting, the whole house has to be heated.

We also don't heat the orangery ever during cold months unless we have friends over and know we will need the big table. Saves a lot as that room with all the glass is an issue to heat. I love it.

The issue is that when they are turned off, the boiler sotll runs. I'm going to see now with the weather getting better from tomorrow, if the boiler still runs during the night on Monday, then I'll call someone.
 
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Toxile said:
Does it have Danfoss port valves? We had the same issues as your describing and it turned out to be one of the 2 port valves that was failing. Changed them both just in case and it cured the issue.
Click to expand...

This was my thought too. If the valve is stuck, it will be holding a microswitch closed calling the boiler to run.
 
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