Boiler Going Rogue

[Prudie]

Can anyone suggest what went wrong with our CH heating - long story below - we will ring british gas on Monday but..

We went away Friday for the night and returned last night. Left the CH on as per settings - target 22, schedule on at 0700 and off at 2130 (Fri-Suns). Newish non-combi boiler (3 months, fitted by BG). On the train home I was bored and looking at apps on my phone so thought I'd check the Hive. I was thrown into a panic as current temp was 27 (still with target 22) and looking at the graph from 8pm Friday night it had climbed to 27, stayed on all night and all day. I felt sick becasue my 2 cats were home and worried the house was on fire. Called my neighbour (who'd been feeding the cats, she said they were fine but she did think the house was hot). Cut a long story short we turned the boiler off via the hive on the train (when we had a signal...)but I was in knots sitting through the last hour or so of our journey. Anyway what would make a boiler keep going and raise the temp to a level we've never set it at?

[Tilly2]

Could it be the app that's at fault?

[bhg481]

It sounds like a room thermostat problem to me. Our roomstat has a digital display so has a battery. If the battery goes flat the thermostat doesn't work.

[Prudie]

Not the app, we both have it installed separately on phones and both showed the same. The daily history graphs are working too, shows the big spike from 8pm onwards, not switching off and the temp of the house all through the night and next day between 26.5 and 27. Apart from that the house was indeed sweltering when we got home. The room thermostat is battery operated - if the battery is going it surely doesn't mean all times and temps are lost and the boiler just stays on and gets hotter and hotter? And surely it warns you too?

[Khandro]

Does it like mine have an outside temperature thermometer which can regulate its output ? If so was the outside temperature colder than when it was set ?

My highly 'advanced' boiler by the way broke down 10 days ago and we are still waiting for an electronic part. I have got electric fires on all over the house burning up juice - still its not burning up oil.  

[Prudie]

No setting would cause it to climb to 27 though, that's unbearable.

[bhg481]

If our thermostat battery goes the thermostat simply doesn't work. The job of the thermostat is to stop the pump circulating the hot water round the radiator system; the boiler provides the hot water as required. If the thermostat doesn't stop the pump it will continue to think the house is not warm enough and keep heating it. It will finally reach a point where the heat provided just balances the heat loss to the outside world and the temperature steadies - 27 deg in your case. Put a new set of batteries in the thermostat before you make an expensice call-out.

[brainiac]

I agree that it could be the batteries in the thermostat.  I had to replace mine the other day as it was showing an error code. It's easy to do: there will be a YouTube tutorial on whichever model it is.

[Khandro]

[Prudie]

It's a 3 month old Hive, surely with all the flash it's capable of  it would display if the batteries were running low?

[bhg481]

Our thermostat is a Honeywell and all it displays in normal operating state is the current room temperature. It's a few years old (I can't remember exactly when I changed it), so fairly modern. I only discovered the battery problem the first time they went flat - in our case the heating didn't come on and the thermostat display was faint.

[bhg481]

Just to be clear it's the room thermostat I'm talking about, NOT the one in the boiler; they serve a completely different purpose. Unless the room thermostat was changed at the same time as the boiler (3 months ago, you said) the roomstat batteries will be more than 3 months old.

[nicebloke1]

Only 3 months old? It maybe a case of rubbish batteries supplied, they never fit the best.

Low battery should show a red battery icon just below the temp. But, not always if the batteries are completely shot.

Simple action to take now, go and get some good batteries, ( Duracell) simple to change, at least then you know if it is, or not.

If that fails you could have a faulty thermo. BG your next move.

 

[Prudie]

It was all put in new at the same time. This is the wall thermostat we have 

https://www.screwfix.com/p/hive-hubless-active-v3-wireless-heating-hot-water-smart-thermostat-white-grey/893JK?gclsrc=aw.ds&gad_source=1&gclid=Cj0KCQiA0MG5BhD1ARIsAEcZtwTd5rr6rDjmQ1OhaXxKzMb89pr5vAxu0dHZrw4lNCbLxrHImRJWnTcaAramEALw_wcB&gclsrc=aw.ds

There is no low battery message and it's also working normally this morning. We will see if it goes off tonight when it should. BG will be called anyway. Thank you for suggestions.