Best replacement for Landis & Gyre RWB2 CH Programmer

[mick2me]

I have just moved into a house with a L&G RWB2 Programmer controlling a Glow-Worm Majorca 246 or 246'N' Combined Central Heating Boiler and Space Heater. With Gas Fire to the front. (C.1977).

There is a Satchwell Thermostat in the hall, which as a cost saving we do not heat. There is a Hall Rad but it is turned off.

The programmer clock is faulty, not running so I intend to replace it with one of the programmer models discussed elsewhere here. But which one is the problem?

I notice that this mechanical programmer does not allow the CH to be on without the water heating. Unless I am missing something on the controls?

Regarding the stat in the cold hall. What control does it have over the system? It still switches on and off so cant be controlled by the stat, or surely it would run continuously.

I would like the Thermostatic control to be in the lounge, bedroom or both.

I see that you can use wireless programmer/stats, which might be best option.

I was formerly an electrician but have no experience of CH systems.
Any advice on replacement of Programmer/Stat for this system would be greatly appreciated

 

[FiremanT]

I notice that this mechanical programmer does not allow the CH to be on without the water heating.

Your system may begravity hot water, which means that it is normally imposible to have heating without water. I.f your pump is downstairs near the boiler and you have no motorised valves, it is probably gravity

I would like the Thermostatic control to be in the lounge, bedroom or both.

A stat in the ounge is o good if you use the gas fire.

 

[hazetimesfive]

gravity hot water... impossible.... say what...

 

[45yearsagasman]

gravity hot water... impossible.... say what...

If thats a query, then please clarify what you mean. I know what the Fireman means.

 

[mick2me]

Thank you for the prompt replies.

Regarding the gas fire part of the back boiler system, the gas fire would be used in milder parts of the year with main CH turned off. I will look into location of any pump?

 

[hazetimesfive]

haha sorry yes now i know what he means as well. im talking about something else altogether


... mind you we dont get much of that round ere so its no wonder i forget it exists

 

[mick2me]

Any comments on this one as a replacement for the RWB2?
Will it work on the same wires that are connected in the RWB2?

http://www.honeywelluk.com/products/Temperature-Controls/Temperature-TPI-Control/Sundial-RF2-Pack-3/

Any other compatible wireless or non wireless?

 

[Hugh Jaleak]

This (I think): http://www.heatingcontrolsonline.co.uk/siemens-landis-staefa-rwb29-programmer-p-43.html should be a direct replacement.

The stat should be able to be replaced by any roomstat, (newer type stats dont need a neutral so disconnect and make safe if present). Stat in a gravity HW/pumped CH system basically switches pump on/off when CH is selected on programmer and room temp dictates CH is required.

 

[mick2me]

Thanks Hugh
I will add that to my list of possible replacements,
I can do some miner wiring modifications if required for programmers that
are not identical. I will replace the back plate with new one anyway.

I do like the idea of a Wireless programmable stat and think its worth the difference in price.

 

[mick2me]

I bit the bullet and ordered one...
http://www.honeywelluk.com/products/Temperature-Controls/Temperature-TPI-Control/Sundial-RF2-Pack-3/

Will see if its a straight replacement?

However what happens to the old stat in the hall, should O remove it?
Or turn it fully up? If I remove it will there be a link to be placed in the
Programmer backplate?

 

[mick2me]

I have replaced the RWB2 with the ST9420c. Nothing now works?

The connections should be the same, but there is no CH or HW?

With CH & HW set to auto, once or cont, CH & HW indicators are on but there is no voltage to either terminal 3 or 4.
There is permanent 240v to terminals 1 & 2.

The original connections to the RWB2 were
Neutral
Live
Term 1: No Connection
Term 2: No Connection
Term 3: brown wire (HW on)
Term 4: red wire (CH on)

Where am I going wrong, this should be a straight replacement according to Honeywell guide.?

 

[mick2me]

Connections...
Only two pairs of live and neutral out from the programmer.

There is a live feed out from Term 3 (HW on)
another from Term 4 (CH on) all neutrals connect to 'N'

From cold both CH & HW the system run heating the water and providing CH.

Everything gets up to temperature. Then everything shuts down.
The stat calls for CH as the room cools down, The CH indicator light comes on and there is 240v to Term 4. However the CH is not firing up.
There is a feed from the programmer to CH.

Run off the hot water for a bath and both the HW & CH fire up and start heating again, until the water gets up to temperature, then it closes down the CH again.

This may be down to what plan I have, and I am not sure which?
Y plan?

Refitted RWB2, all working perfectly?

Anyone any Ideas?