Central Heating/Hot Water timers

GreeBo

Hey,
Ive posted on this before but Im just as confused now as I was then...

Basically I want to have a timer for my hot water and a timer for my heating.
It appears that I will have to have two, otherwise I need to run cable in awkwards places and I couldnt be botheres

So, I have a "timer switch" and a "cylinder thermostat" from B&Q, however it appears that the cylinder thermostat needs to connect to a pump or motorised valve to switch off the source to the cylinder.
Can I not just wire the thermostat & timer in series so that if the timer is on the thermostat thermostat decides if the immersion needs to "fire" or not?

any advice greatly appreciated...

antoinolachtnai

if all you want to do is switch the electric immersion on and off, then you only need a timer, surely?

Eurorunner

I don't mean to hijack this thread but I have a similar query. I've moved into a new build and got the builders electrician back as the immersion wasnt working. They said that the cylinder thermostat was dead and that they would come back and replace it. I would prefer to have a timer just like the original poster. Can I buy a timer somewhere and get the sparks to put it in when he puts in the new thermostat? Would I be right in thinking this would involve little if any extra work for him?
If so, what timer should I get (links?).

311

Normally you would stick in a manual dial timer ,the one with loads of pins on it.
They cost the electrician about 15 euro to buy ,theres about 40 minutes work in putting it in ,wouldn't say it would cost anymore than 80 euro to supply&fit

Eurorunner

_Brian_ wrote:

Normally you would stick in a manual dial timer

What other types are there?

GreeBo

well the one I bought is digital...
Has settings to 24hour, 5/2 day, 7 day
3 on/off periods per day
1hour boost feature

JamesM

GreeBo wrote:

Hey,
Ive posted on this before but Im just as confused now as I was then...

Basically I want to have a timer for my hot water and a timer for my heating.
It appears that I will have to have two, otherwise I need to run cable in awkwards places and I couldnt be botheres

So, I have a "timer switch" and a "cylinder thermostat" from B&Q, however it appears that the cylinder thermostat needs to connect to a pump or motorised valve to switch off the source to the cylinder.
Can I not just wire the thermostat & timer in series so that if the timer is on the thermostat thermostat decides if the immersion needs to "fire" or not?

any advice greatly appreciated...

Some people are getting confused - like me !

Are you talking about a cylinder thermostat which straps on to the cylinder at a certain level, so that you can just heat a required amount of water? This usually works from the oil or gas heating and the thermostat usually controls a motorised valve. This type of stat may not be able to take the stronger current of an electric immersion. If the stat can handle it, then you should link it between the timer and the immersion.
I think that the thermostat that Eurorunner is talking about is built into the immersion.
Jim.

GreeBo

JamesM wrote:

Some people are getting confused - like me !

Are you talking about a cylinder thermostat which straps on to the cylinder at a certain level, so that you can just heat a required amount of water? This usually works from the oil or gas heating and the thermostat usually controls a motorised valve. This type of stat may not be able to take the stronger current of an electric immersion. If the stat can handle it, then you should link it between the timer and the immersion.
I think that the thermostat that Eurorunner is talking about is built into the immersion.
Jim.

yeah lots of confusion, most of it mine
I bought the thermostat in the hopes of linking it to the immersion timer.
Right now the immersion seems to get the water to about 90 degrees!
I'll open it up tonight and take a look at what its set to...my guess is that its just buggered...
From reading the instructions on the stat I bought it does seem to be for a valve or pump so it wouldnt be able to take the immersion current. Im thinking major fire hazard.

So I guess its returns at B&Q time...again!

Regarding the actual timer I got....its just called a timerswitch...do I need a special immersion timer to handle the load?
There didnt seem to be any in B&Q...Im wondering now how the whole bath/sink part will work with a timer.

JamesM

If the water is going to 90, it probably means that the stat in the immersion is set very high, or bust !
Jim.

Copper

The timer switch you got should be fine so long as its rated for at least 20 amps.

The cyllinder stat you got sounds like its one used to control a motor valve- don't use it unless you're sure it can handle the immersion current.

The easiest way to wire it is to break the mains cable going into the immersion switch (the on/off-bath/sink switch) through the timer, (pull the mains out, put it into the timer and take a feed out of the timer back to the immersion switch).

The timer now replaces the on/off switch at the immersion switch.

GreeBo

Yeah that was my plan allright, Cheers .
does anyone know if there is a timer specifically for an immersion, i.e so it has a setting for bath/sink?

I think I'll just bring the cylinder stat back and check out the immersion stat, maybe its just set uber high.

Spfeno1

GreeBo wrote:

Yeah that was my plan allright, Cheers .
does anyone know if there is a timer specifically for an immersion, i.e so it has a setting for bath/sink?

I think I'll just bring the cylinder stat back and check out the immersion stat, maybe its just set uber high.

Greebo,

I just bought one yesterday in Michael Garry Electrical on Bolton St. - its analogue and specifically designed for bath/sink immersion timer switching.
Hope this is some help - cost €45 ish inc. VAT

P.S.
I had intended fitting this myself and I also bought 2 mtrs of extra cable just in case I didn't have enough. My problem is that the cable supplied is four core - green/yellow(earth), brown, black and blue - does anyone have any suggestions on how to wire this

antoinolachtnai

I would boldly suggest that one core is for the earth, one for the neutral (common to the two immersions), one is the live for the immersion at the top of the tank (the 'sink' immersion) and the other is the live for the immersion at the bottom of the tank (the 'bath' immersion).

I am not an electrician and obviously if you are not sure you should take proper advice from a professional.

GreeBo

yeah thats what Id also suggest, especiaily if its designed for an immersion!

Generally what sort of rating should an immersion need?
Im concerned that my B&Q switch timer is not suitable for an immerison.
I'll check out the rating of the timer when I get home, but what does it need to handle for an immersion?

Copper

A standard immersion has 2kW/3kW rated elements. The sink element draws around 9 Amps and the bath element draws around 13 amps.

The maximum current drawn by a standard immersion is therefore around 13 amps, (since they can't both be on at the same time)

Your timer should be rated for at least 13 amps, but they are normally rated for standard values (10 amps, 20 amps, 32amps etc). So the short answer is you should have a timer rated for 20 amps!

Also, an immersion is a resistive load, (just a large kettle really), so there are no extra considerations for switching the load ie "special" switches suitable for immersions; so long as your switch/timer is rated for the immersion current its fine.

GreeBo

Copper wrote:

Your timer should be rated for at least 13 amps, but they are normally rated for standard values (10 amps, 20 amps, 32amps etc). So the short answer is you should have a timer rated for 20 amps!

Cheers, the switch says 6 (2)A so I guess its not suitable for an immersion, I'll just use it to replace the analog heating timer..
what does 6(2)A signify?

Copper wrote:

Also, an immersion is a resistive load, (just a large kettle really), so there are no extra considerations for switching the load ie "special" switches suitable for immersions; so long as your switch/timer is rated for the immersion current its fine.

By "special" I mean that takes the two settings (bath/sink) into account not just on/off...

cheers.

GreeBo

hey,
Ive spent a week trying to find an electronic timer suitable for an immersion and I just cannot find one.
I dont care if its dual or single anymore, I'll just use the existing bath/sink switch but I'd really prefer an electronic one over an analog type.

anyone point me in the right direction?
Also what does a rating of "6 (2)A" mean?
Cheers!

Hoagy

I bought a Greenbrook T23-B digital immersion time switch in B&Q for abiyt 45 euro. Maybe it's out of stock where you looked?

The rating 6(2) A means 6amp resistive or 2 amp inductive, which means it will happily switch 6amps of heating load for example, but only 2 amps of fluorescent lighting or pump motors.

GreeBo

thx for the explanation!

Which B&Q did you get it in?
Ive been out in Liffey Valley a few times over the last 2 weeks or so and no sign...
I might try Tallaght, though its smaller so probably unlikely...

How long ago did u get it?

Hoagy

I got it in Liffey Valley last year.
The timer is still listed on the Greenbrook.co.uk so maybe B&Q are not stocking it any more.
A phone call to B&Q Newry might be helpful.