S Plan Wiring

[rookery34]

I have an Ideal Classic RS 260 wall hung balanced flue gas boiler. It
has Two, Two Port Diverter Valves and is wired with a Lifestyle Heating Control Pack and LWC1 wiring Centre. I think this is an S Plan System.

The boiler is in my garage and also has a Sunvic TLM 2257 frost stat at the side of the boiler. I have got this set at 5 degrees and now the cold weather has started,the boiler and heating sometimes come on in the middle of the night,even if the Programmer is off.

Fine, i assume the Frost stat has kicked in and done its job. Great so far.This morning at 4am i went downstairs and looked at the setting on my room stat. I turned it right down and it switched the boiler and pump off.
Has this been wired correctly,surely the frost stat should not be controlled by my room stat,i would have thought this should be wired independently and go off when the temperature around boiler and stat have gone above 5 degrees. If i accidentally left my room stat on low could i end up with frozen pipes in my garage? Also i have been told i need to fit a pipe stat to save money.The frost stat is wired with 3 core and earth and does not connect to the boiler.This has a separate cable to it which i assume goes to the wiring center or Programmer. The Programmer is in the kitchen and has a fused spare at the side of it.

Any advice would be much appreciated as i am worried about frozen pipes. If this is the case i will get a sparky in to have a look.

 

[D_Hailsham]

You have an S Plan system.

One motorized valve controls the heating system, the other the HW system. The frost valve will be connected to the wiring centre so the heating valve is opened when the Frost stat turns the boiler on. If it didn't, water would not be able to circulate.

Yes, you need a pipe stat. The frost stat tells the boiler to turn on if the temperature drops below 5C but, at present, there's nothing to tell it to turn off. (Though the room stat may have been wired to do this???)

The normal way is to connect a frost stat (set 5C) and a pipe stat (set 20C) in series. The frost stat closes when temp falls below 5C; the pipe stat opens when water temperature rises above 20C.

Both stats should be wired so they work independently of the programmer and room stat.

 

[rookery34]

Thanks for that,not sure why it is wired like that. I thought i might be able to wire the pipe stat myself.but it obviously isn't as easy now the room stat has been added in to the wiring. Can you suggest anything?

Thanks

 

[Blagard]

If all your stats/controls go directly into the wiring centre (which is good practice) it should be easy to move the switched live from the frost/pipe stats to the other side of the room stat so it switches the motorised valve without passing through the room stat.

Your biggest problem may be the number of terminals available to add in the pipe stat!

FYI the fused spur probably feeds into the programmer to give it a live feed. After that all the wires will go to the wiring centre. The boiler wiring should also go to the wiring centre as it gets its switched live from the motorised valves when one is opened, not directly from the programmer.

 

[rookery34]

Cheers for that, i feel happier now i know it has been wired with good practice,just need to get a pipe stat and have a go at fitting that thanks again.