Heat slave 20/25 oil boiler heating problem

[Aqueousosprey]

Hi all

Hope someone can help me fix this problem!

I have a 20/25 boiler that is giving me trouble. The heating does not come on automatically in the mornings or afternoons. If I go to the boiler and tap / ping the front of the boiler between the hot water and heating green control knobs i hear a click and away she goes!
I thought it was a sticking relay on the control board so I replaced that and it is unfortunately still the same!!
The hot water works as it should and we are only having trouble with the heating.

Anyone had a similar problem or have any ideas?

Any help much appreciated

aqueousosprey

 

[oilboffin]

It maybe that you have a loose connection on one of the thermostats check all the connections.

 

[simond]

If your 20/25 has the optional HW/CH programmer recessed into the panel, this is often the source of loose connections internally. You could try (if you are handy with LX) looping the CH timer outputs and seeing if the problem goes away.

 

[oilhead]

This is usually a problem with the PCB or the programmer. By pass the programmer connections and see whether the problem persists to isolatethe source.

 

[Aqueousosprey]

This is usually a problem with the PCB or the programmer. By pass the programmer connections and see whether the problem persists to isolatethe source.

Thanks for your reply, how would I bypass the programmer connections?

 

[Aqueousosprey]

If your 20/25 has the optional HW/CH programmer recessed into the panel, this is often the source of loose connections internally. You could try (if you are handy with LX) looping the CH timer outputs and seeing if the problem goes away.

Thank also for your reply, the boiler does have how/ch programmer on the panel, I will check for loose connections on this. Not sure how to loop ch timer outputs but i am willing to give it a go if you could give me a bit more info on how and where to do this?

 

[Aqueousosprey]

It maybe that you have a loose connection on one of the thermostats check all the connections.

Thanks, I'm not really sure where the thermostats are sorry!
are they incorporated in the green temperature switches to adjust the water and heating temp on the front of the boiler.?

 

[Terrywookfit]

Thank also for your reply, the boiler does have how/ch programmer on the panel, I will check for loose connections on this. Not sure how to loop ch timer outputs but i am willing to give it a go if you could give me a bit more info on how and where to do this?

Connect the Brown, White and grey wires together.

 

[oilboffin]

Yes they are on the back of the dials they are push ons and sometimes come loose.

 

[Aqueousosprey]

Yes they are on the back of the dials they are push ons and sometimes come loose.

Ok..... I've checked all the connections to the pcb and to the back of the dials and I have ( I think) found something ... when I used to turn the heating dial I think I heard it click in two places ( lower and upper limits of the temperature thermostat) ?? I now hear no clicking at all when turning the heating dial.
Is it meant to click? Have I found my problem?

 

[Terrywookfit]

Use your multimeter not your ears !!!

 

[Aqueousosprey]

Use your multimeter not your ears !!!

Fair point !

can anyone then explain the correct procedure to test it? How it works? Having not done this before it's a bit of a SLOW learning curve..

It has three wires coming from it
Pink centre (1), orange left (c), and yellow right (3) they go to x13 connector (heating stat)on the pcb that has an additional wire going to the boiler high limit thermostat.
Any help much appreciated

 

[Terrywookfit]

With a demand for heating, relay 1 should activate and supply the pink wire with 240v.
If the stat is calling for heat the orange wire will be live. Which feeds burner via other stats.

Or =common
Pink = demand
Yell = satisfied.

 

[Aqueousosprey]

With a demand for heating, relay 1 should activate and supply the pink wire with 240v.
If the stat is calling for heat the orange wire will be live. Which feeds burner via other stats.

Or =common
Pink = demand
Yell = satisfied.

Thanks for this info I really do appreciate your time. ok so I've tested the pink and orange wire with boiler set to heating on and heating stat turned up full and I have no power going to either. One quick ping on the front and I heard the relay click and 240v turns up.... any ideas where to look now?

 

[Terrywookfit]

Voltage on Brown and grey wires at X4 ??? (To neutral not across them) !!