Discuss Old Firebird 90 thermostat issue? in the DIY Electrical Advice area at ElectriciansForums.net
Thanks for the update.Hi sorry not had the chance to check the timer until tonight below I've attached the readings, all other terminals are not live with the mains on.
The L and number 2 have the mains power.
Both valves are on auto not on manual
It only has two electric valves, another thing I noticed also is that when the mains is on and it fires up (power to the timer but not switched to on to open the valves) the valves are powering up and opening anyway.Thanks for the update.
I don't understand why you have a voltage on terminal 2, which is the signal for "HW off", which I thought was only ever used for Y-plan systems.
Can you remind me - is the motorised valve you have a 2-port (pipe in and out) or a 3-port (3 pipe connections, one coming up opposite the motor)?
Update: having refreshed my memory of what's inside a 3-port valve, if you do have one, then I would expect there to be a voltage on terminal 2 as indicated by your meter (being fed via diode and resistor in the motorised head), assuming the valve was in the CH position.
If you do have a 3-port valve/ Y-plan system, and assuming wiring is traditional y-plan, then I think the wire currently in terminal 2 (which you measured live) should actually be in terminal 1. I'm assumoing that brown wire goes to the cylinder stat.
I believe normally the "CH OFF" terminal is not used, and the "HW OFF" terminal is used.
You might try transferring that wire, but I'm not convinced it will necessarily fix the problem!
Thank you for the clarification.It only has two electric valves, another thing I noticed also is that when the mains is on and it fires up (power to the timer but not switched to on to open the valves) the valves are powering up and opening anyway.
I just don't understand how it's just decided to do the continuous running off the mains. As it didn't happen with any one of the alterations or new items within the setup.
Thank you for the clarification.
Now I understand it is an "S-plan" system, that makes things clear.
I thought it might be a motorised valve problem, but now you say that the minute you turn the setup on, both valves motor on whatever the programmer setting, so now I'm thinking the programmer is not doing the right thing!
You will see from the diagram that the valves are supposed tonsupply the power to the boiler, but only when they are activated. What is turning them on other than the programmer?
The wire on terminal 2 of the programmer shouldn't be there in a typical 2 valve system, so I would suggest disconnecting it, isolating the end, and trying the setup again.
View attachment 113907
Thank you for the clarification.
Now I understand it is an "S-plan" system, that makes things clear.
I thought it might be a motorised valve problem, but now you say that the minute you turn the setup on, both valves motor on whatever the programmer setting, so now I'm thinking the programmer is not doing the right thing!
You will see from the diagram that the valves are supposed tonsupply the power to the boiler, but only when they are activated. What is turning them on other than the programmer?
The wire on terminal 2 of the programmer shouldn't be there in a typical 2 valve system, so I would suggest disconnecting it, isolating the end, and trying the setup again.
View attachment 113907
I understand the diagram and what your saying, there was no re wiring required for the new valve just plugged it in.Thank you for the clarification.
Now I understand it is an "S-plan" system, that makes things clear.
I thought it might be a motorised valve problem, but now you say that the minute you turn the setup on, both valves motor on whatever the programmer setting, so now I'm thinking the programmer is not doing the right thing!
You will see from the diagram that the valves are supposed to supply the power to the boiler, but only when they are activated. What is turning them on other than the programmer?
The wire on terminal 2 of your programmer shouldn't be there in a typical 2 valve system, so I would suggest disconnecting it, isolating the end, and trying the setup again.
If you replaced the motorised valves, are you sure the motor supply wires (blue and brown) go to the correct places.
ie you have wired the valve brown wires to their respective thermostats, not directly to live mains?
View attachment 113907
OK, so as if you replaced valves like for like, and just plugged in the existing cables as it were?I understand the diagram and what your saying, there was no re wiring required for the new valve just plugged it in.
So the valves must be getting power from the 'timed' side of the timer, else the boiler would carry on when you pulled it out!So both valves come on as soon as the mains is switched on, they can't be controlled via the controller at all, only way is to pull off the timer and then it cuts out (or switch of mains)
I don't know why there are two wires. The second could be the live feed for the microswitches in the valves.There is two lines coming into the (L) is that right? Is that for both the valves?
Yes I agree that rather suggests it cannot be a fault in one valve, it's something elseAs testing before I unplugged each valve seperately and it was the same (powered up via mains with no control from the timer) so wouldn't that rule out the valves?
Traditionally there would be a 'wiring centre' where wires from supply, timer, valves, boiler all congregate, and that's where the fault finding is usually undertaken. It looks to me as if that Hensel junction box on the right might be your wiring centre - is that where the cable from the timer and internal cables for the motorised valves go?If it's not raining tomorrow I'll get out and have a decent look hopefully
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