Gas Back Boiler Timer thermostat help.

[Briansmad]

My mams thermostat went off. So we bought a new one. This one has 3 wires connected instead of two like the old one. All wires were in the back of the timer, I have taken the the wires out and put them in a junction box and followed instructions. The thermostat now only turns the central heating pump on not the hot water / heating like the old one did. Lifestyle LP112 programmer / timer with RTS 1 thermostat.
These are wired in a seven way junction box as follows,
Thermostat = N*N C*L H*3.
Pump= L*5 N*2 E*3.
Boiler = L*7 N*2 E*3.
Programmer = N*2 L*1 3*7 4*4.

Is it possible to link these, so heating turns on with pump or heating/water comes on with pump when thermostat kicks in??? Thanks.

 

[dal5band]

Sounds as though you havn't connected the HW side. The thermostat should only control the heating so that part sounds OK.
Look at the HW "on" side of the timer - where is that connected to ?

Need more details the system. Are there any motorised valves controlling the CH and HW ?

 

[Briansmad]

No moterised vavles just Back boiler, pump, thermostat.
Back boiler = hot water Boiler = L*7 N*2 E*3.
Programmer = N*2 L*1 3*7 4*4

So boiler live goes to 7 on juction box and no 3 from programmer goes to 7 on jucnction box.

First wiring diagram on these instructions. http://www.invensyscontrols.com/NR/...B28-54E2A7F60534/0/LPrangenewInstructions.pdf

 

[Briansmad]

First wiring diagram on page two of these instructions. top right corner of page two. all wires from timer/programmer/boiler/pump and thermostat go into junction box.

 

[gas4you]

Thermostat will only operate the pump, not the boiler. Boiler will be controlled by hw side of programmer. This is why you can't have heating without hot water

 

[Briansmad]

Yes but at the moment only the pump powers on when the thermostat kicks in. the central heating light or hot water light on the programmer do not kick in. So the pump will be on 24/7 and only pumping cold water unless i maually turn the hot water on. Thks.

 

[gas4you]

Is the LP112 set to gravity hw on the dip switches?

 

[Briansmad]

No idea if it has any dip switches. I have never seen them It did say set to G but not sure where they are/were.

 

[gas4you]

Remove the front of programmer but undoing grub screws underneath I think and lever forward. Dip switches are usually on the back of most programmers.

 

[dal5band]

If you do not have motorised valves, the programmer must be set so you can't have CH on its own.
The programmer should only allow HW or (CH+HW).

Because you don't have motorised valves to direct the flow, the HW works on gravity (boiler on only) and the CH works on the pump and assumes the boiler is already on. So you have to have (CH+HW) on together.
If the HW gets too hot, you have to turn the boiler thermostat down slightly.

Just looked at your programmer diagram - link should be in "G" position (as you said)
A note says the contacts are volt free (no power)and to connect live to pin 1 as well. Somehow you need to make the live available

 

[Briansmad]

not sure about this? = A note says the contacts are volt free (no power)and to connect live to pin 1 as well. Somehow you need to make the live available.
Thermostat is already set to 'G', I read another post about lp112 which said wiring needs to be in parallel nor series. I just followed instructions))

 

[dal5band]

All in all, I think you need an electrician or CH engineer to resolve.

 

[dal5band]

Just to correct what I said above - the volt free contact business refers to the timeswitch not the programmer - you were right !