Replacing Honeywell ST6300A with ....

[paraboy]

..... upgraded Honeywell ST9400C. I have had the old programmer for about 4 years and it is not energy efficient for me considering the price of gas these days, the programmer will turn on my heating but at the same time the water is also on unless you physically turn of at the programmer.

What I want is a programmer that independently turn on the heating with no hot water and vice versa.

Would it just be a case of taking one programmer of the wall and replacing with new one or do I need an electrician for the work.

Also looking to replace my old thermostat which is the dial type with a digital one, any thoughts or advice very much appreciated.

 

[paraboy]

Anyone

 

[denso13]

What I want is a programmer that independently turn on the heating with no hot water and vice versa.

Your existing programmer is capable of that. Given that you can't work it like that I suspect it is your heating pipework rather than the electrics which would need altered. Would need a lot more info on your existing pipework layout to be able to advise.

 

[paraboy]

Thanks denso13 for the reply, what I have is a Worcester Bosch system gas fired condensing boiler with a hot water cylinder tank and a cold water tank in my loft, any help much appreciated.

 

[45yearsagasman]

Got anything like this? View media item 38425 View media item 44939

 

[paraboy]

Yip 45yearsagasman and thanks for your reply, got 2 of them in my hot water cylinder cupboard, one is marked HW in black marker and the other one is marked RADS. Am I any closer to getting my question asked.

 

[paraboy]

Got a reply from email to Honeywell to say that the programmers are compatible but since found out from them that I need to have a pumped system and not gravity fed, now totally bamboozled as I don't have a clue what my system is. Can anyone help, much appreciated.

 

[Boilerman2]

Oh well! (a little knowledge is a dangerous thing!) it could be a wiring issue or as already stated a hydronic issue with your pipe work layout sadly my Crystal ball is unable to log into your system for me to see what the actual problem is!

 

[45yearsagasman]

Paraboy, post a pic of the valves in situ and I bet you have a pump close by. That would make your system a fully pumped S plan.

 

[paraboy]

Hope this pic is clear enough, I cannot see where possibly there could be a pump. Thanks for your help.

 

[Daveydub]

Hi Paraboy,
You did say that your boiler was a system boiler therefore (if this is correct) pump will be in boiler case.
I can not remember these clocks, perhaps somebody else can, but some of the old honeywell clocks had a small plastic lug on the heating slider control which could be in 2 positions. One position would pick up the hot water slider control when you moved it. The other position it would not. This therefore made the clock suitable for gravity or fully pumped installations.
If your system is wired properly then you could switch the clock to the second option and switch heating only on.

Turn ch & hw to off and allow pump over-run to finish
Turn off mains supply to clock
Remove front of clock and look at the rear of the clock while operating sliders.
Can you see a small plastic lug which ties the heating slider to the hot water?
Screwdriver slot will turn this lug so it is out of the way.
Reassemble clock, turn mains back on, switch on ch only and check that it operates, turn on hw only and check that it operates.
Hope this is of some help

 

[paraboy]

Cheers Daveydub, I am at work on night shift so will post a pic of my programmer tomorrow, thanks for the info it's very much appreciated.

 

[paraboy]

Here we have my programmer, this morning my heating was on for an hour to take chill off house but at the same time the water will come on unless you either physically get up and overide it or slide the switch to off the night before but then you need to remember to switch it back for hot water later on. Not very economical or people friendly.

 

[Daveydub]

Sorry paraboy, I misunderstood your original question.
What I believeyou are wanting to do is to set different times for hw & ch and you can currently turn heating on or hw on independently.
Some systems can only have heating on if hot water is also on and this is what I thought your problem was.
The Honeywell ST9400 range will allow you to control each circuit seperately and is available as 24 hour or 7 day model.
If you are reasonably handy with these things then replacement is straightforward
Inside the clock you will have LNE connections which power the clock.
You will then have a Live (when hw ON) feed which opens the hw Zone valve.
You will also have a Live (when ch ON) feed which opens the ch valve.
When the valve opens an internal microswitch makes contact to provide power to pump & boiler.
Sometimes the clock is used as a junction box so there are lots more wires inside and it looks a bit baffling but all other connections stay exactly as they are.
The diagram shown on Honeywell site for S plan explains in detail, terminal 3 hw on, terminal 4 ch on, ignore pump and boiler connection as paragraph re "pump over-run boilers" in notes applies to you.
Hope this helps

 

[paraboy]

Thanks Daveydub, so what you are saying is that I will be able to go ahead and install the ST9400c and I will be able to independently have HW and CH at my mercy, thanks for your advice its very much appreciated.