Problem with heating not coming on more than once (hot water is fine)

Andrea15

Hi,
I have a Valliant EcoPlus Pro. it is about 10 yrs old and it has always worked fine. This morning I noticed that the analog timer wasn't working, so I went and bought a new one (the original one is a 130 and I have found a 150, but I am told they are interchangeable). Now the timer works, BUT I have noticed something else.
1) You turn the boiler on at the wall
2) you turn the heating on
3) you turn the heating off
4) you can't turn the heating on again without resetting it/turning it off at the wall. The hot water is fine in any configuration you like (as long as the boiler is on, that is).
I have tried both with the timer and bypassing it using the "always on" switch. With the old and new timer assembly the behaviour is the same (minus the timer bit that is stuck).
I wanted to add a picture of the timer assembly, but it seems I can't attach anything (and links don't work either).
Any advice?

Le_Kirk

Just put the picture on using a broken link and a regular will fix it for you, having first checked it.  Why do you keep turning it off; surely that is the job of the new timer you have just fitted?  What do you mean "you can't turn the heating on again" what happens?

Andrea15

I was Just trying to explain what is happening.
If I try to turn the heating to "always on" or if the pins in the timer are in "on" position, the heating will come on only once - that is if the previous action was to turn the boiler off and on again.
If the previous actions was to turn the heating off, it won't come on again. 
I don't know how to explain it any better 🤣

FreeBear

One of these ?

https://www.vaillant.co.uk/homeowners/products/vaillant-timeswitch-150-control-3713.html

Andrea15

Yes. That's the one.
Actually the original is a 130, but I am told the 150 would work just the same. 

Le_Kirk

Andrea15 said:

I was Just trying to explain what is happening.
If I try to turn the heating to "always on" or if the pins in the timer are in "on" position, the heating will come on only once - that is if the previous action was to turn the boiler off and on again.
If the previous actions was to turn the heating off, it won't come on again. 
I don't know how to explain it any better 🤣

What causes the heating to go off after you have set it to "always on" or it has been called by the time setting pins?  Is there a boiler fault indicated?  Did you check for any wiring differences between the 130 and the 150?

Andrea15

Once the heating is on, it stays on (as far as I can see...). Once it goes off if because the pins tell it to or I turn it off, then I cannot turn it back on.
No error message and all the "right" lights are on.

The 130 and the 150 do look different. All you see is some number of pins that click into place, 5 for the 130 and 4 for the 150, but from what I read it should work fine. I even phoned Vaillant yesterday and was told to get the 150.
The timer assembly is all enclosed, so I don't know what it looks like in the inside. It just slots into place at the front, no other work required. 

Le_Kirk

All I can think is that you have not selected another "ON" period with your setting slides (pins).  If you set it to come on at 06.00 and off at 08.00, you need to have another "ON" period set.  Are all the other slides/pins set "outwards"?

Andrea15

I have tried all sort of combinations. In any case, I don't really need the pins. All I need is to turn the switch to ON (see above link), which means "always on, ignore pins". That too works only once.

Le_Kirk

There must be something happening with the boiler then.  Before you changed the timer, was the boiler working OK?  When you turn the boiler on by using the "ON" switch the boiler fires up - yes?  Does it then come under the control of the thermostat?  What happens when the room reaches temperature and the 'stat turns the boiler off?  When the temperature drops does the boiler fire up as normal?  When you get the problem of "ON", "OFF" and it won't work when you try "ON" again, what alarms or indication is there on the boiler panel?

[Deleted User]

Le_Kirk said:

There must be something happening with the boiler then.  Before you changed the timer, was the boiler working OK?  When you turn the boiler on by using the "ON" switch the boiler fires up - yes?  Does it then come under the control of the thermostat?  What happens when the room reaches temperature and the 'stat turns the boiler off?  When the temperature drops does the boiler fire up as normal?  When you get the problem of "ON", "OFF" and it won't work when you try "ON" again, what alarms or indication is there on the boiler panel?

This is very often the reason heating doesn't fire up again, isn't it, if the OP selects a higher temp it will probably cure the 'problem'.