Gravity fed programmer wiring advice

Buffy 330 · Aug 27, 2022

A question if I may before I dive in.
I have an old gravity fed CH system which thanks to members here in the past - works very well.
It has a Danfoss Randal 3060 programmer that has died.
I have the original installation docs for the programmer - and it shows 7 terminals plus the earth.
In the wiring diagram from Danfoss - terminals 3 and 5 are not used.

I took my cover off , and they are used , so this is the beginning of my problem.

I have traced all wires and have the following.

Room Stat
Frost stat
Hot water stat
Central heating pump
Hot water pump
Boiler
Power supply

Ive drawn a schematic to try and get my head around this , but when looking for compatible replacements for 2 channel controllers , that reference to 2 terminals is still missing in the various cross reference tables.

Ideally - I would like to know how to wire each of the 6 components into a controller please ?

Many thanks

Steve

Avo Mk8 · Aug 27, 2022

As you say terminals 3 and 5 don't seem to be connected to anything within the programmer.

[ElectriciansForums.net] Gravity fed programmer wiring advice

But Danfoss does suggest using terminal 3 as a (L) connection for a gravity system (see below)

.

I suggest they have been used purely as parking terminals to connect wires together - which would be supported if there are at least two wires in each of those terminals.

See if your schematic makes sense if you assume these are just connecting blocks, and the wires don't require any connection to the programmer?

Buffy 330 · Aug 27, 2022

Avo Mk8 said:
As you say terminals 3 and 5 don't seem to be connected to anything within the programmer.
View attachment 100975
But Danfoss does suggest using terminal 3 as a (L) connection for a gravity system (see below)
View attachment 100974.

I suggest they have been used purely as parking terminals to connect wires together - which would be supported if there are at least two wires in each of those terminals.

See if your schematic makes sense if you assume these are just connecting blocks, and the wires don't require any connection to the programmer?

This does make sense as terminal 3 and 5 have 2 wires in each - and as you suggest - a connection.

If this is the case - then a like for like substation to a newer model - whilst following the manufacturers terminal arrangement would be pretty easy

The schematic can be uploaded if required ?