st699 wiring problem

rbrstr · 19 Feb 2013

Need a little help please. I fitted a new honeywell 4073 3 port valve on saturday and was unable to get the boiler to fire afterwards for HW and CH. ive checked my wiring a million times and finally sussed there is no boiler and pump live feed to the airing cupboard. im at a loss as to why?

i had a look at the wiring for the controller(st699b)
if i remove the fascia and connect the link wire from L-5-8 and switch it to L-4-8 i can get HW controlled nicely by the slider and stat but no CH

confused!

Y-plan system

DP · 19 Feb 2013

look at the wiring for three port valve; you are missing a wire me thinks

ive checked my wiring a million times

I think now it will be a million plus 1

rbrstr · 19 Feb 2013

DP said:
look at the wiring for three port valve; you are missing a wire me thinks

ive checked my wiring a million times

Click to expand...

I think now it will be a million plus 1

hiya,
orange live feed, white and grey wires, blue neutral and an earth. 5 wires

DP · 19 Feb 2013

What can I say that I have not already said in my post. LOOK AT THE Y PLAN wiring.

if i remove the fascia and connect the link wire from L-5-8

Why would you want to move the wires link from L-5-8?

rbrstr · 19 Feb 2013

DP said:
What can I say that I have not already said in my post. LOOK AT THE Y PLAN wiring.

if i remove the fascia and connect the link wire from L-5-8

Click to expand...

Why would you want to move the wires link from L-5-8?

because if i connect the link wire to L-4-8 i can at least get some hot water. L-5-8 does not supply a feed to my airing cupboard at all, so i have nothing

I dont understand what you mean by a missing wire and my system is wired the same as a y plan diagram.

matt1e · 20 Feb 2013

rbrstr said:
my system is wired the same as a y plan diagram.

your ST699 is faulty,for starters but why have you got a cable connected to number 4 anyway? That's not yplan,
well it is but not one that is wired as per your valve if what you are doing is making a difference
I take it there is one connected already prior to moving the link?
what make was the previous valve?

Matt

rbrstr · 20 Feb 2013

matt1e said:
rbrstr said:

my system is wired the same as a y plan diagram.

Click to expand...

your ST699 is faulty,for starters but why have you got a cable connected to number 4 anyway? That's not yplan,
well it is but not one that is wired as per your valve if what you are doing is making a difference
I take it there is one connected already prior to moving the link?
what make was the previous valve?

Matt

Thanks Matt, the ST699 is not faulty. i thought it was too so i bought a new one and it made no difference!
In trying to diagnose the fault i looked at several wiring diagrams for the st699, one of which counted from right to left not left to right, leading me to think the link wire should be on terminal 4 not terminal 5, i hope you see what i mean? the wiring diagram is the "honeywell 4073a" .pdf

when i wired the link wire incorrectly like this i discovered i could have hot water! (we have had no hw or ch for 4 days! getting a little desperate here)

i have also discovered if i add an additional link wire from L-4 4-5 5-8 i can also have CH but not both simultaneously.

the previous valve was a SUNVIC SDM 1901

DP · 20 Feb 2013

The motorised valve actautor wiring need not be connected, and you should still have hot water during HW calling. So, your wiring is incorrect!!

rbrstr · 20 Feb 2013

DP said:
The motorised valve actautor wiring need not be connected, and you should still have hot water during HW calling. So, your wiring is incorrect!!

even with the MVA wiring disconnected the boiler would still need a live feed to fire up.

mikely · 20 Feb 2013

If you have wired as per: http://www.honeywelluk.com/Documents/Full-Install/pdf/1083.pdf then with the link on the ST699 as shown L-5-8, you will get live fed to your tank stat on C or 2 (depending on HW on or HW off). So not sure what you mean by ‘L-5-8 does not supply a feed to my airing cupboard at all’.

What wiring diagram have you used?

rbrstr · 20 Feb 2013

mikely said:
If you have wired as per: http://www.honeywelluk.com/Documents/Full-Install/pdf/1083.pdf, then with the link on the ST699 as shown L-5-8, you will get live fed to your tank stat on C or 2 (depending on HW on or HW off). So not sure what you mean by ‘L-5-8 does not supply a feed to my airing cupboard at all’.

What wiring diagram have you used?

That link you posted doesnt work but thanks, i'll see if i can google it

i used a honeywell .pdf but this one is identical http://octaveblue.co.uk/c_heating/hw1_ch1.htm

rbrstr · 20 Feb 2013

mikely said:
If you have wired as per: http://www.honeywelluk.com/Documents/Full-Install/pdf/1083.pdf, then with the link on the ST699 as shown L-5-8, you will get live fed to your tank stat on C or 2 (depending on HW on or HW off). So not sure what you mean by ‘L-5-8 does not supply a feed to my airing cupboard at all’.

What wiring diagram have you used?

ah, that link works without the comma on the end, yes thats the one im using

what i meant by" L-5-8 does not supply a feed to my airing cupboard at all" is, if i put my circuit tester on the orange wire from the 3 port valve in the connector block in my airing cupboard, there was no voltage

im off work today so am trying different things. I have re-wired the ST699 back with the link wire in the correct position. would a faulty HW thermostat cause this issue? what i mean is... if the HW thermostat was stuck in a constant satisfied state, would this prevent the boiler from firing even the CH?

mikely · 20 Feb 2013

Sorry about the comma!

I think it’s unlikely that your tank thermostat is faulty, but possible. To check, try disconnecting it and testing continuity through it. If possible, change its state by varying the set temp.

With HW on at the programmer, you should get live at terminal 6 of the wiring centre. If the tank stat is demanding heat you should get live at terminal 8. That is the feed to the boiler and pump which should then run. This is as shown in the octaveblue animation.

rbrstr · 20 Feb 2013

mikely said:
Sorry about the comma!

I think it’s unlikely that your tank thermostat is faulty, but possible. To check, try disconnecting it and testing continuity through it. If possible, change its state by varying the set temp.

With HW on at the programmer, you should get live at terminal 6 of the wiring centre. If the tank stat is demanding heat you should get live at terminal 8. That is the feed to the boiler and pump which should then run. This is as shown in the octaveblue animation.

Thank you.Ive just tested that and the thermostat (L641a) works correctly, but, when the stat reaches the desired temp, shouldnt terminal 7 then become live? HW off? i have this connected to the grey wire on the 3 port valve but this wire is not live at any point

D_Hailsham · 20 Feb 2013

How a mid-position valve works has detailed fault finding instructions.

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st699 wiring problem

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