Help! Am2 coming up and need help with the s plan

[Abdul-Baasit Zaman]

Hi everyone, my am2 is fast approaching and i need help with understanding how s plan wiring works. I understand the different parts in the system and how its wired but i cant seem to figure out how the solar sustainable element fits into the system. Also can anyone let me know anything else i should look out for during my am2. Many thanks in advance

 

[Loki]

I came upon this wiring diagram when I was researching info on the AM2.

 

[Loki]

Also came across these

 

[Abdul-Baasit Zaman]

Also came across these

View attachment 48016

View attachment 48017

Thank you.. will have a look

 

[Zdb]

You get given the diagram in the exam so as long as you stick to it and use the correct type/size cable that's stated you will be fine.

 

[Conteh]

I came upon this wiring diagram when I was researching info on the AM2.

View attachment 48015

Do you have to wire the link on the 2 channel timer between L and 5

 

[Lister1987]

Good info on here;

Central Heating Control Wiring

Wiring diagrams and information regarding central heating control wiring

www.flameport.com

 

[EricMark]

25th Feb 2019 original post, would expect he has sat his exam by now? I will admit I have looked at central heating wiring for non modulating boilers and simple enough, but as soon as a modulating boiler is involved then it starts to get complex.

Turning off a modulating boiler because your going out to work, or going to bed is simple enough, but what you don't want is to turn a boiler off/on by an external control rather than let the internal controls modulate the boiler.

What we want is a thermostat which will not cause the boiler to cycle on/off either the TRV wants to control through the water temperature or by connection to the ebus of the boiler. Better if latter is used, so you can only use one ebus thermostat on a boiler, so if split into zones, then the two thermostats has to be some how blended or changed according to if one or two zones are used.

 

[KarimR]

Hi all,

Does anyone know if we need to wire in the link for the Channel timer between L and 5 in the diagram?

 

[EricMark]

Hi all,

Does anyone know if we need to wire in the link for the Channel timer between L and 5 in the diagram?

What channel timer in what diagram this thread was about an exam question, if you have a new question start a new thread.

 

[KarimR]

What channel timer in what diagram this thread was about an exam question, if you have a new question start a new thread.

The diagram above is what I am referencing to, not a new question the same as one already posted but not answered.

anyways no bother as I did the wiring today and sorted it out.

incase for anyone else the link needs to be put in otherwise the system doesn’t work. Look at the wiring diagram for the channel timer and there is a wire going from L to 5 that’s the link I was referring to.

 

[EricMark]

John Ward (Flameport) has a U-tube and website full of useful stuff, still do not know which diagram you were referring to, the S plan has moved on with the use of modulating boilers, using thermostats like the EPH it can control the motorised valve with one output and the boiler with the OpenTherm output with the thermostats set as master and slave.

It seems although not looked into it the Drayton Wiser also has a module to work OpenTherm and still contracts for the motorised valves.

Central heating wiring is not as simple as before the boilers started to use the latent heat from the flue gases, as the return water temperature is now important. And boiler output is turned up and down not on/off.

This has been made more complex as the plumbers seem to think the TRV does not form a zone, the LABC it seems does consider a TRV produces a zone so can't blame the law, it is the way some plumbers have interpreted the law. So it seems there are only two thermostats the EPH and Drayton which can handle zone valves, and only Drayton Wiser can handle zone valves and TRV electronic heads as well.

So we have a load of clever systems which simply will not work with new build houses due to way they are plumbed. The Worcester Bosch have not adopted OpenTherm and is very hard to get to run efficiently in a zoned new build, and we see a load of botched up systems as a result.

Linking the two zone valves together and using electronic TRV heads is likely the best way around the problem, and Hive have designed an on/off control with electronic TRV heads which will work with Worcester Bosch and other boilers which are not OpenTherm enabled.

However wifi linked TRV heads are not cheap, think Hive around £55 each so with 14 radiators that becomes rather expensive, so we normally use some compromise, some wax TRV heads, some stand alone like the eQ-3 or Terrier i30 and some dedicated to the wall thermostat heads.

We I went to collage and Uni it seemed they were out of touch with costs, simple maths if the annual fuel bill is £500 and very clever control can reduce that to £400 and the central heating system has a projected life of 10 years then the maximum worth spending on the controls is £1000. So we may have TRV heads which are IFTTT enabled and can be set to geofence, but will it save enough to be worth while, and will they work where your live?

I watch my wife returning from Shrewsbury to put on the kettle and make her coffee, up to Welshpool works reasonable well, but the last 10 miles the map shows she is still 5 miles away and she is walking in the door, Nest Gen 3 does seem to have turned on the heating when we both go out, and looking at the temperature reported on the TRV heads it does seem it did turn off, but very few times do we both go out, and there is no history while we are out to say if it worked or not. And even if it did over the two years fitted we have both left house together around 10 times, so at around £1 a time saving that's £5 per year, I need to live to 500 to get money back.

 

[KarimR]

I came upon this wiring diagram when I was researching info on the AM2.

View attachment 48015

This was the diagram I was referring to the link for channel timer on top right. I just did my AM2 and was exactly this set up to wire up.

 

[EricMark]

You are correct it would not work, there is no supply to 15 on wiring centre or 2 on the programmer, neither is there any tank thermostat, as shown you would rely on the solar for domestic hot water.

 

[KarimR]

You are correct it would not work, there is no supply to 15 on wiring centre or 2 on the programmer, neither is there any tank thermostat, as shown you would rely on the solar for domestic hot water.

I only wish I had your understanding on this system haha. Unfortunately as a improver you hardly ever get the chance to work on these and then expected to understand fully the operation and wiring is a little hard. But fingers crossed I did well. Thanks for your messages. Take care