Boiler fires up when heating and hot water are set to off.

Myser

colourblind wrote: »

Thanks Myser, I think you are right, there must be a fault within the wiring somewhere.
Would you recommend an unvented plumber or an electrician to investigate?

If you've checked whether you have a frost stat as rightly mentioned by 'Jonesya', an electrician familiar with central heating electrics should be able to correct the wiring.

However, since you have an unvented cylinder, it's probably best to contact someone who holds a ticket to work on unvented systems.

idkwia

gas4you wrote: »

I would hazard a guess that the hot water zone valve is stuck open, rather than opening from an 'unknown' demand, thereby constantly keeping the boiler etc on.

Turn off all power to the heating system and see if you can hear of feel the valve shut.

If it doesn't you need a complete new valve fitted.

Also, if this is the case, you now don't have the zone valve working as a 'safety device' for the unvented cylinder.

gas4you - sorry to hi-jack this thread but I tried to PM you but seems you are not accepting PMs anymore as I assume you were getting too many. Anyway, I note you are in Norfolk and I am wondering if you could help my 86 year old father who lives in Hunstanton please? He has a gas fire in his living room which has stopped working. I have no idea what is wrong with it except to say that when you press the ignition there is no click but don't know if there was one before. He has other heating and being the summer it is not urgent but I am hoping that you could help him please? I live almost 3 hours away so I need someone reliable who will give him good service. Can you help please?

colourblind

Thanks guys for you help.

There is no mention of frost protection in either of the manuals.
The boiler is located in the kitchen and the Megaflo is in the upstairs bedroom, so i guess that would not be the case anyway

I will speak to suitably qualified plumber this week and get them to have a look.

I must admit it is a weird one!!:wall::wall::wall:

southcoastrgi

Myser is correct that you need someone with a G3 cert to work on an unvented, however this sounds more like an electrical fault, so i would say you need a good heating engineer or a good sparkie that knows about heating wiring, you would be surprised at the amount of installers that have the G3 but wouldn't have the first clue when it comes to wiring

gas4you

idkwia wrote: »

gas4you - sorry to hi-jack this thread but I tried to PM you but seems you are not accepting PMs anymore as I assume you were getting too many. Anyway, I note you are in Norfolk and I am wondering if you could help my 86 year old father who lives in Hunstanton please? He has a gas fire in his living room which has stopped working. I have no idea what is wrong with it except to say that when you press the ignition there is no click but don't know if there was one before. He has other heating and being the summer it is not urgent but I am hoping that you could help him please? I live almost 3 hours away so I need someone reliable who will give him good service. Can you help please?

Not certain why I am not receiving your PM's. (just looked. It will be because you are a new member I think) I do get them still from others.

The problem with me going to Hunstanton would be the cost, as for me it will be at least an hour each way.

This would make me a financially unrealistic option for your father.

I would recommend looking on the Gas Safe website and entering his postcode to search for an installer.

Mr_Ted

Myser wrote: »

A stuck microswitch in a zone valve can cause a boiler to fire continuously however, a zone valve actuator can only open if the programmer is enabled for heating or hot water and the respective thermostat is calling for heating/hot water.
With the programmer removed and a zone valve actuator still opening, there is clearly something wrong with the wiring.

OR IT'S STUCK:p

colourblind

Think we have finally sorted the problem.
Went on holiday for a week and switched off the boiler.

When I turned it back on, the boiler wouldn't work at all. Checked the fuseboard to find it had tripped. Reset the trip and it tripped again.
Spoke to my friendly plumber who came straight over to investigate.
He found that one of the two way ports was leaking water internally into the motor/microswitch assembly and reckons it was shorting the switch to make the boiler fire up. Also the pump had a small amount of condensation/water within the electrical housing, so he changed both units. Even I know water and electricity don't mix!!

We think that when it was doing it before and with the water being hot, it was quickly evaporating and therefore only calling for a short period.

So far so good!!!!:beer: