Randall 103 Replacement

[dazzy04]

Hi all,

This is my first post, so please be gentle!

I am looking to replace a broken Randall 103 central heating programmer from an old system. The pre-selector switch is broken so the timer element no longer works.

I have been given a Danfoss 102 timer. I notice that on its selector switch it has Water only/Off/Water and Heating instead of Timed/Off/Constant. The 102 will physically fit into the wallplate/terminal block, but how would the connections be affected?

From what I can see, the 102 would work on a timed basis, but there would be no way of selecting for it to be on all the time. Does this sound correct?

I'd be grateful for any comments on this.

Darren

 

[REDSAW]

danfoss do a wiring diagram online pdf which shows exactly how to wire up and which models are a straight swap over.

 

[jtsplumbing]

You can still get the 103, if you want to up-grade to one with digital clock fit the 103e straight swap.

 

[tamz]

A 102 will plug straight onto a 103 base as long as it hasn't been used as a junction box for other wires. If there is nothing connected to terminal 2 you are good to go but you will only be able to time your heating and the closest the tappets will move is an hour apart so if you want it on constant and work it from a room stat put the 4 on off tappets at times throught the night like off 2am on 3am off 4am on 5am
Really you should spend 20 odd quid and buy a half decent clock as the old danfoss's have seen their day.
They don't come much cheaper than this one which is fairly decent
http://www.NoLinkingToThis/p/horstm...rch-_-SearchRec-_-Area2&_requestid=289447#_=p

 

[dazzy04]

Thanks, Redsaw, JTS and Tamz for your advice.

Think I'll use the 102 temporarily until the Horstmann one is back in stock locally.