Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is ON

[rojroj]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

Just wondering if the Links were left intact (not cut) to cater for non-standard wiring ?
If you are sure that cutting the Links 1 & 6 wouldn't make it any worse, let's go for it.

 

[doitmyself]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

Just wondering if the Links were left intact (not cut) to cater for non-standard wiring?

Unlikely. How would the installer know which links to leave and which to cut - the workings of the Honeywell are a mystery as dismantling one is not possible.

If you are sure that cutting the Links 1 & 6 wouldn't make it any worse, let's go for it.

Link 1 is cut if you have a programmer, not a "basic timer". The difference between the two is that the programmer allows completely separate timings for CH and HW (e.g HW from 6am to 7am, CH from 6am to 9am) while the basic timer only provided common times for both. The Honeywell ST6400C is definitely a programmer, so you should cut Link 1. It presumably connects two "programmer" terminals together in the Wiring Centre.

Link 1 has to be cut if you have a boiler with pump overrun. The fact that it is not cut could explain why your pump runs when it shouldn't.

I would go for it! We then know that any remaining problems cannot be caused by the wiring centre.

PS Your wiring centre is not popular as it's not possible to see exactly how things are wired together. Most pros just use a 10-pair terminal strip in a junction box. Honeywell also sell them and all their wiring diagrams are based on them. Here's the "standard" wiring diagram for a Y Plan (hold cursor over to enlarge).

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[rojroj]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

OK, I've measured the Voltages in the Wiring Centre (obviously with the Programmer removed) - not sure if it will add any value.

Boiler Terminals :
Between Live & Neutral / Earth = 240 V ~
Between Switched Live & Neutral / Earth = 10 V ~ (3V DC)
Between Pump Live & Neutral / Earth = 0 V ~ / 0 V DC

Pump Terminals :
Between Live & Neutral / Earth = 0 V ~ (Boiler / Pump is not runniong)

Programmer Terms :
Between Live & Neutral / Earth = 250 V ~


Room Stat Terms :
Between Live & Neutral / Earth = 10 / 16 V ~ / 4 V DC


Voltages in the Valve (with Programmer removed) :
Between Orange & White – 10 / 16 V ~

Voltages in the Valve (with Programmer connected and CH ON) :
Between Grey / Orange / White and Blue / Earth – 250 V ~


The only thing that appears to be glaringly wrong is the Voltages across the Live (1 - Red) and Call (3 - Yellow) on the Actual Room Stat :

A) Sometimes it is 240 V ~ even when the CH is OFF (@ Programmer) - I think this is when the Programmer is ignored and the Stat controls the Firing of the Boiler (Boiler ON when Stat calls for Heat even if the Programmer CH is OFF).

B) At other Times - it is 0 V (I guess that Call / Yellow also gets 240 V from somewhere) - I think this is when the Stat is ignored and the Programmer controls the Firing of the Boiler (Boiler ON when Programmer CH is ON even if the Stat doesn't call for Heat).


Anyway, please cross check the above to see if you can spot any other irregularity.
If not, let me know and I'll cut the Links 1 & 6 and take it from there.

 

[doitmyself]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

OK, I've measured the Voltages in the Wiring Centre (obviously with the Programmer removed) - not sure if it will add any value.

Anyway, please cross check the above to see if you can spot any other irregularity.
If not, let me know and I'll cut the Links 1 & 6 and take it from there.

Now you are just using delaying tactics!

CUT THE LINKS

Report the results.

 

[rojroj]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

The Links were cut yesterday and manual testing seemed to have worked as it should.
Will observe for a couple of days with Programmed timings and update.

 

[rojroj]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

Good News. It appears to be sorted. The Programmer and the Room Stat are working in conjunction and turning the Boiler ON only when the Programmer is ON and the Room Stat calls for Heat.
It was the cutting of the Link 1 which sorted the issue.
Thank you so much for all your time and help - much appreciated.

One final question.
While replacing the Mid Position Valve, the Plumber drained the system and I wanted to put Sentinel X100 into it before re-filling it so that it went inside the System. However, the Plumber wanted to test his work first, so he re-filled the System with water first and then asked me to put the X-100 on the small Expansion Tank in the roof. Would it be enough ? Will all the X-100 enter the System or would you suggest that I drain it again and put the X-100 first before re-filling it.

Thanks again.

 

[doitmyself]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

Good News. It appears to be sorted. The Programmer and the Room Stat are working in conjunction and turning the Boiler ON only when the Programmer is ON and the Room Stat calls for Heat.
It was the cutting of the Link 1 which sorted the issue.

That's good to know

Will all the X-100 enter the System or would you suggest that I drain it again and put the X-100 first before re-filling it.

If the system was not drained sufficiently for the X100 in the tank to get into the system it tend to stay in the tanks. though it will eventually trickle down as the water level rises and lowers due to the water heating/cooling.

If you want to make sure it's got into the system, get another can of X100 (it doesn't matter if it has been over-dosed).

If you are in a hard water area, you should also add X200 to the system - one can will be enough. You can add it at the same time as the X100.

Do the following when the system is cold:

Tie up the ball valve
Drain water via a drain valve downstairs until the water level is just above the bottom outlet of the tank.
Add the X100 (& X200)
Untie ball valve so the level rises to normal
Tie up ball valve
Drain until level is just above bottom outlet
Untie ball valve

Most of the X100 (& X200) will then be in the system with a small amount left in the tank.

 

[rojroj]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

Thanks again.

 

[david dimbleby]

Re: Boiler starts whenever the Room Stat calls for Heat - even when the Programmer is

hello. would appreciate any help. I too have this strange situation where the room stat calls , regardless of the controller setting. I have triple quadruple checked all my wrirng- it is correct. the issue seems to be that there is a permanent live into the stat - from the controller on the CH ON wire, regardless of its state. I thought it just a faulty controller then and purhcased a new one - exact same !
baffled now.
hot w works fine. ch works fine - in so far as only controlled by the stat!
worcester boiler.
drayton digistat. ( 3 wire)
drayton 5 / 7 day timer controller(s)
pump set / wired in over-run mode - all THAT works fine. just why am i getting a perm live out the controller on CH line - back to the junc box , and thus to the stat. there is NO OTHER cross wiring or anything that i can see explains this - but it s the same with 2 diff controllers.....