Trianco ALways on?

[inditime]

HI,

I have a Trianco Eurostar 65/40 oil boiler for my central heating and hot water tank. Works fine for heating and hot water during the times it is set on the controller. However, the boiler fires up and wastes a lot of fuel outside of its timed times.
The 3 way valve and water pump work fine. The boiler is serviced every year, and has no problems. It doesnt have a frost guard so shouldnt fire up when it gets freezing, and I have no thermostats. So now im stumped as to why it fires up when it feels like it.
Any suggestions would be helpful.

 

[inditime]

Any ideas anyone?

 

[dontknowitall]

The boiler is fine. (It's job is just to heat!)

From your description I suspect the zone valve, programmer or pump in that order. Probably only one of these but could be two or all of them. This is assuming the room stat and TRVs are working/set at the correct temperatures.

Another possibility is a loose wire somewhere in the system but this is rare.

 

[inditime]

Thanks dontknowitall,

I agree, the boiler is just a heater. Can you confrim that my model doesnt have any water pumping ability, that's the job of my water pump surely.

I replaced the controller with a new unit, but it still fires up at will. The controller has a six pin connector, but only 5 wires are being supplied to the controller.

I took the wiring junction plate apart and one of the wires (of the 6 core going to the boiler) was cut short and not connected to anything.

Im looking for a wiring diagram to see what it might of been connected to in the past.

 

[papahape]

when you replaced programmer did you replace like for like ?

My first thought is that the motorised valve has a fault and is sending a constant live to the boiler which means that it doesnt matter what the programmer/ controller does the boiler will be getting power .

 

[inditime]

Thanks papahape,

I did change like for like controllers. I did a test of putting the old controller back in, it works just the same, so I chnaged it back to the new one, and thats still there now.

 

[papahape]

if you have changed the programmer and checked that the wiring is the same as MI then this woudl lead me to believe that tthat it is the zone valve

 

[WHPES]

You really should have a thermostat fitted as with just a timeclock it will not be efficient and must be costing you a fortune in oil.

 

[papahape]

why was the programmer changed ? did this problem ( constantly on ) happen before or after the change ? could the loose wire come from the change over ? what is the make of the programmer and I can see if I can help find the wiring diagram and as whpes says it def would be advantageous to have room stats fitted as the only control you actually have is through the boiler and cylinder stat and this could also be a big factor on the fuel costs

 

[inditime]

The controller I have currently fitted is a Drayton Tempus Seven. I would like to fit a thermostat, but not sure of how it should be wired. The (constantly on) has been happeming before and after I changed the controller. I changed the controller because I thought it might of been faulty, but it isnt as the boiler is still firing up out of timed times.

As for a fault that may cause a constant live, well, from looking at the wiring junction box, the boiler is fed a constant live all the time, as it is wired to live in the junction box.

And yes, it does cost a fortune in oil.

 

[dontknowitall]

If you go to the Honeywell website (Honeywell United Kingdom Heating Controls) you can find wiring diagrams which should help you.

 

[kimbo]

I think we need to know more, has it always done this or has it just recently happened, if it recently happened I wwould rule out the wiring. I would go for the three port valve typical problem you might find that one of the microswitches is stuck on probably on the hw side.

 

[inditime]

dontknowitall, I had a look at that Honeywell site, but couldnt find any wiring diagrams for my system.

kimbo, it has always happened, and I havent changed any wiring. The controller only ever has had 5 wire feeding it.

So with the 3 way valve, and the microswitches, are you saying that the 3 way switch controls the on/off function of the boiler, and not the controller. This would lead me to believe that the controller only controls the 3 way switch. As the boiler has a constant live feed.

Am i half way right or not at all?

 

[papahape]

http://www.heatingcontrolsonline.co.uk/instructions/LP.pdf

try this as I think it is the same schematic and it does look like there should only be 5 wires on the back plate , does the ch come on when you have requested hw only if so then probably the micro switch bit of trial and error required me thinks 🙁

 

[kimbo]

As far as I can remember the call for hot water and heating is on the white and grey which drives the motor to the required position, it then activates the boiler and pump via the orange wire, you need to find if there is a live from the orange and then back track it. Y plans are always tricky s plans much more straightforward and reliable.