Fitting a timeswitch

[jcr1987]

I've just bought a Sunvic Select 107XL timeswitch to replace my currently working, but old, manual switch so we can set the heating to turn on and off at specific times from our combi boiler. I half expect a response of "get a professional to do it", but I'm wondering whether it's easy/safe to fit it myself.

I've taken the cover off the old switch and there's just the black and red wires (neutral & live I assume) connected to the switch. I'm no sparky so, whilst the diagram on the box look relatively straight forward, I don't want to go and do something stupid like short out the entire house. Is it as straight forward as connecting the respective wires to the N & L points in the new timeswitch, turn it on, set the timer and off it goes? All i want it to do is turn the heating on and then turn the heating off without me having to be there to do it.

Details of the timeswitch are here if this helps.

http://www.uk-plumbing.com/sunvic-time-switch-select-107-p-42014.html

Cheers
JCR

 

[EliteHeat]

Why didn't you buy a programmable thermostat?

P.S. Oh, and get a professional to fit it

 

[Paul Barker]

You can't put a timer on the main power switch or you won't have hot water.

Your combi will have a position which is presently bridged by a loop of wire that should be interrupted preferably by a programmable room stat. This will be either volts free, 24v or 230v, or you may have the option of either. It all depends which combi you have.

 

[jcr1987]

Forgive me for being a bit dim, but...

If the current old thermostat I have merely turns the heating on when I slide it up, and turns the heating off when I slide it down, then what's the difference with the timeswitch i've got to install now? Surely it does the same thing, except it does it electronically rather than manually in that I can set it to turn on and off at specific times.

There are only 2 wires (red and black) that feed into the current thermostat from a long wire that comes out of my ceiling (from the boiler I assume) so why wouldn't it work if i merely wired these up to the N and L ports in my new timeswitch? I don't see why it would affect the hot water.

If I haven't got the right product for the job I need it to do, can someone tell me which one will suit the purpose. I understand this may be difficult without seeing the current thermostat and boiler I have however.

 

[EliteHeat]

Forgive me for being a bit dim, but...

If the current old thermostat I have merely turns the heating on when I slide it up, and turns the heating off when I slide it down, then what's the difference with the timeswitch i've got to install now? Surely it does the same thing, except it does it electronically rather than manually in that I can set it to turn on and off at specific times.

There are only 2 wires (red and black) that feed into the current thermostat from a long wire that comes out of my ceiling (from the boiler I assume) so why wouldn't it work if i merely wired these up to the N and L ports in my new timeswitch? I don't see why it would affect the hot water.

If I haven't got the right product for the job I need it to do, can someone tell me which one will suit the purpose. I understand this may be difficult without seeing the current thermostat and boiler I have however.

Aha! now I understand. You have an existing room thermostat that you use to control the heating and this is the only control that you have. You want to swap it out with a 107XL timeswitch. You currently have two wires going to the stat from the boiler.

Nah, won't work. The L & N connections on the 107 are the power supply to the unit. Terminal 3 is a switched live supply. The unit requires an earth so you are at least 2 wires short.

Of the two wires that you have, one will be permanently live, the other will be the switched live from the existing stat - this starts the boiler up for you when there is a demand for heating.

What you actually need is a battery operated programmable room thermostat. This operates a volt-free relay when there is a demand for heat, which simply bridges the two boiler terminals mentioned earlier in Paul Barkers post. The two wires that you have are very possibly the wires from the bridge - but do not assume this until it has been checked.

But, to be honest, I would get someone on to look at it 'cos apart from anything else, we still don't know what boiler you have.