DRAYTON 30002 Digistat Installation

[mangomine]

I am wanting to replace a Satchwell TLX2284 thermostat with a Drayton 30002 & am somewhat confused re the wiring.
The satchwell has 4 wires yellow/red/blue/earth.
I have wired the drayton as follows:
yellow..... ON
red......... COM
blue....... N
Leaving the Off connection empty.
My problem is :
The digistat appears to switch on/off with the temp as required,
however, when the system is switched off on the timer/controller, for some reason the heating comes on at a very low setting.
Should i be connecting something to the 'Off' connection ???.
Any assistance would be greatly appreciated.

 

[doitall]

You only need Com-On.

How low is low, is it or a frost stat present.

If the timer is off the stat doesn't work unless you have wired something wrong.

Is the boiler actually coming on or is it just the stat saying it is below the set temperature.

 

[mangomine]

whilst i was out today with the timer in off position the boiler must have been on as the temp showing on the boiler was 36 deg & the rads were warm when i returned.
around 5am this morning i heard the pump working & the boiler showed 25 deg. so far from being cold enough for the frost stat to kick in.
are you saying i am wired correctly by leaving no wires to the 'OFF' connection ?.
hence me asking what wires go where.

 

[doitall]

You can't really get it wrong unless it was wrong in the first plase.

Red-com, yellow-On

What is the timer make/model and where is the red connected.

Are there any motorized valves etc.

More info in other words.

 

[mangomine]

there are no motor valves.
timer is a drayton LP722 & i cannot see where the leads go into it.
I have the red on com & yellow on the on, leaving me with a spare blue lead which was connected to the previous stat... so ...where should this fit, i currently have it in N, leaving the OFF connection empty .
there is a pic of the connections on the drayton site for the 30002 stat.
Thanks for your patience, am currently operating the system by the main on/off switch by the boiler.

 

[doitall]

You have wired it correctly.

If you have a multimeter you can check whether the red or yellow is connected to 4 in the programmer.

If the stat still works when the htg program is off it points to a faulty programmer.

 

[mangomine]

I can't see the programmer being faulty is only a few months old & not been used a lot.
managed to remove it from the backplate.
No. 4 has a brown lead into it.
don't have meter but got test lamp & lead.
what do you think about me having 3 leads going into my previous stat, from what you suggest, the blue lead is not required ?.

 

[doitall]

Forget the Blue and just connect it to N in the stat, you don't need it or the HTG off.

The next question is where does the brown in 4 turn to red.

The signs still say motorized valve around the cylinder somewhere.

 

[mangomine]

Unable to see where brown goes ...disappears through wall into trunking with other cables.
Found motor valve at side of tank, lever is in auto position.
cannot see how this has been moved Etc.

 

[doitall]

So the most likely explaination is a duff actuator or stuck valve.

Can you post details about the MV please, there should be a make and No on it somewhere.

 

[mangomine]

Motor valve is Honeywell No. on it .....V4073A 1039.
I find it hard to believe this can be at fault as it was working perfectly prior to me fitting new stat.
I am contemplating re-fitting the old stat to check the system & see if it works perfect..i have a feeling it will.

 

[mangomine]

Thanks for your help doitall.
I think problem solved.
There is an option on the stat that if you left the house for a few hours, you can press a 'set' button to lower the stat, the temp would reduce & tick over & then when you return, you press set again & it returns to your regular temp.
all i can think was that in my confusion i had pressed the set button & somehow it overrides the off switch on the timer...i have no tried it & don't really need that option..so many thanks & all now ok.