Replacing a Randall 4033 timer

Hi All,

I am a complete idiot when it comes to central heating, and we have just moved into a new house. On arrival I found that the timer dial on our Randall 4033 timer is not spining, although I can hear ticking.

Heating / water is able to be switched using the switches, but I want to swap this timer out.

After a quick sweep of this forum, I have seen some great posts about what can and cannot be done, and it seems that I should be able to just go and get a new timer (prefereably a more modern one!) and replace it (that part I would be ok with - Can do elastictrickery!)

What I am unsure of is the type of programmer that I should be looking at. Any recommendations would be greatly appreciated.

Here is the link tot eh Randall 4033:

http://www.plumbworld.co.uk/766-1375

Regards,

Steve

While you are about it, why not replace it with a programmer which controls the temperature and the time ?

Hi,

I am not entirely sure what you mean.

The current timer controls both HW and CH.
The problem is that the dial is not spinning hence our heating and water is on full time.

I want to replace the timer with a more modern one, perhaps with progammable times for each day.

The advice I was asking for was for a suitable replacement.

Regards

Steve

As far as I know, there is no direct swap option for one of these. You will almost certainly find that there is is a horrible mess of wiring behind the cover. Remove one wire and you will be lost forever!

Any digital twin channel programmer will do, so whatever works with your decor will be fine.

You will also need a new wiring centre - the Drayton ones are easily the best - to connect everything up.

If you understand heating systems, like most on here do, then often the easiest way of achieving the swap is to carefully disconnect all of the wiring and then identify all of the components that the wiring is connected to and then rewire it all properly using the wiring centre. You will need a multimeter for this.

The components that you need to identify are the room stat, cylinder stat, pump, boiler, mains supply and lastly the boiler itself.

Obviously you should make safe and not attempt to do any of this is you are unsure of completing it 'cos you won't be popular otherwise.

Once all of the bits and pieces are identified, it is a relatively easy matter to hook it all up. If you have a conventional "Y" or "S" plan then the wiring diagrams are available of the Honeywell site.

For what it's worth, you should add a double pole isolating switch to the boiler supply as well.

www.danfoss-randall.co.uk Do a product search and the wiring diagram for 4033 is in there.

namsag said:

www.danfoss-randall.co.uk Do a product search and the wiring diagram for 4033 is in there.

Click to expand...

Well that's sucked all of the fun out of that then! - looks almost conventional. I'm willing to bet though that there is still a tangled mass of wiring stuffed somewhere other than in a wiring centre.

Ha! Looks easy enough, although knowing my luck I'll take the cover off and a plate of spaghetti with a few crusty old spiders will fall out.

I will have a look for a digital timer and see if I can find one that is simple enough to fit.

Cheers!

Totally agree with you elite . No wire colour will match up and you think how the F did they get all those wires in one terminal... Followed by at the end .Now where did this last one go

OK guys, so - after looking on the danfoss/randall site, I found this one..

http://danfoss-randall.co.uk/xxTypex/287408_MNU17416279_SIT313.html

In there it talks about gravity vs pumped hot water. Erm.. Ce?
I have an immersion tank that our how water is stored in, would that be gravity fed then? I don't think we have a special pump that comes on when we turen th hot water tap on...

That aside, does this look like a suitable replacement?

Steve

That will be fine, but you will have to rewire the new backplate as it is not compatible with your current one.

With regard to gravity/pumped; If you have independent control over heating and hot water i.e. you don’t have to have the HW on in order to get CH then you are fully pumped. As a check, count the number of pipes coming out of the top of your boiler, if there are four (or more) then you have gravity HW.

P.S. Not to confuse the issue, don't worry too much it you don't have a wire in terminal 3 of your old backplate.