Removing an old HW timer

[Milnefish]

Hi,

I am looking to remove an old HW boost timer, but we still want the power to go to a fused switch for the new boiler and timer.

 

[Deleted member 267285]

Do you have a photo of where (assuming the Horstmann is being removed) is a bit further back? I can’t see the flex cable, so can’t work it out in relation to the spur and Drayton.

 

[Milnefish]

The Horstmann is below the fuse box in a hallway and the cable runs through the loft to the spur at the other side of the cottage.

 

[Deleted member 267285]

Sorry, just re-read, the boost will be for the immersion heater(s), so shouldn’t be linked to that spur. So should be removable without affecting the boilers supply.

 

[Milnefish]

Hi CBW,

Thank you for the reply. I just need to figure out which cable is which as they run behind the consumer unit, then how to re wire.

 

[SUNRAY]

Can we confirm you wish to remove the Drayton timer and the cabling to the immersion heaters.

 

[Milnefish]

We have fitted a new combi boiler and the Drayton will be controls for that, but the feed to the spur is on the old horstmann timer. So only has power when the timer is put on.

 

[SUNRAY]

You're saying the switched fuse in the pic is controlled by the Horstmann?

Prior to the Horstmann there should be some sort of isolator/fuse

 

[SUNRAY]

You're saying the switched fuse in the pic is controlled by the Horstmann?


Prior to the Horstmann there should be some sort of isolator/fuse

 

[Deleted member 267285]

It might need to be tested/traced with testing equipment, but possibly terminals 3 and 4 which are the on peak demands.

 

[SUNRAY]

As Chris says it needs testing to verify what you have there, but the basic expectation is the wires in 3&4 need to be connected to the wires in 7&8

and the wires in 1&2 (the off peak feed) is to be removed.

 

[ericmark]

I would assume the original cistern and cold water tank is being removed. So no longer any immersion heaters? So all you need is the live feed, however one does need to be careful, my father-in-law had the immersion removed when solar panels fitted (hot water not electric) and the installers did not fully investigate so left a switch marked immersion heater in his kitchen which since now no immersion he switched off, which turned off his solar panels, just missing a label.

But clearly your not DIY fitting the Combi boiler, so I would leave it to the installers to work out how to set up controls. So any errors are down to them, you don't want at a latter date arguments as to who's fault non operation is, specially if a call out ends up with being caused by a simple wrong label.

It seems we are not allowed to use common sense any more as to when heating should be switched off, for years as a lad if it was a warm day I would not light the fire, which with central heating would be simply switching it on, or off. Seems today's humans are thick, and we have to have thermostats, and other sensors to automate when central heating runs.

Technically not required, as the TRV in every room will control heating room by room, including if fitted timers in the TRV heads to work out when to heat each room, all done with water, and pairs of AA cells. However the boiler may have anti-cycle software, but it will still fire up every so often and pump water through the by-pass valve to see if any room requires heating unless some master automated off switch it fitted, in the main this is a wall thermostat, but could be a hub, heat link, or some other name for the unit.

So the installer will likely need to fit some external controls, and will likely use some of the existing wiring, so he does not need to run new wires, and to follow the regulations he will issue a minor works or installation certificate to cover the work. Together with gas or oil certificates. If he can't do any of the work, he will sub contract to some one who can, you really don't what to get involved.

 

[Milnefish]

Thanks everyone….. we are going to use a single socket for the feed to the new controls and remove the old spur and wiring all together.

 

[SUNRAY]

Thanks everyone….. we are going to use a single socket for the feed to the new controls and remove the old spur and wiring all together.

If that existing fused switch is in the right place.
If it is controlled by the Horstmann,
If all the cables pass behind the consumer unit.

Then while removing the Horstmann and the 2 cables from the consumer units, it makes perfect sense to divert the cable into the vacated MCB/RCBO rather than plug into a less convenient socket and lose other use of that socket.