pump or gravity
- Thread starter j77drs
- Start date
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Right. Now we are getting somewhere.
As I suggested earlier, the person who installed the system had to make some "adjustments", i.e b*st*rd*s*d it, to account for the fact that the SM400 does not have an HW OFF terminal. Fortunately the Drayton does, so it may be possible to rewire so you get completely independent control over heating and hot water. This all depends on how easy it is to run a new cable from the Drayton and from the HW cylinder thermostat to the junction box into which everything is connected. You will need a 5 core cable (earth not necessary) for the Drayton and a 3 core (with earth if required) for the HW thermostat.
The alternative is to keep the existing cables and run an additional single wire to the Drayton and the HW thermostat.
Could you also check the wiring for the Honeywell valve? There are five wires: White, Grey, Orange, Blue and Green/Yellow. Can you tell me which ones are connected in the junction box?
I had the same problem after installing solar at home, i needed to have the heating only option.
The old clock did not have enough wires but it was easily remedied by resiting the new controller to the cylinder cupboard and the existing wiring then had enough cores to complete the job.
The old clock did not have enough wires but it was easily remedied by resiting the new controller to the cylinder cupboard and the existing wiring then had enough cores to complete the job.
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This all depends on how easy it is to run a new cable from the Drayton and from the HW cylinder thermostat
i like the idea of the above
is it as easy as running 1 wire ??
would this mean i still have a GRAVITY SYSTEM ?
i like the idea of the above
is it as easy as running 1 wire ??
would this mean i still have a GRAVITY SYSTEM ?
You do not have a gravity system! You have a kludged fully pumped system.
By adding an extra wire to the new programmer and an extra wire to the cylinder stat, you will have a fully functional pumped system.
It is obviously neater to run a five wire cable to the programmer, but it is more expensive. The same goes for the cylinder thermostat.
Apart from running the extra wires, you will have to alter the connections in the junction box which connects everything together. Let me know what sort of box you have and I can tell you how to change the wiring.
currently i have teh timer set @ G and its heating the water ok, should i change this to P even though the hw comes on with CH ?
When i put the timer on, all wires were connected together etc by electrical blocks, there is no box so to speak ?
When i put the timer on, all wires were connected together etc by electrical blocks, there is no box so to speak ?
Until you sort the wiring out, you will have to leave the timer on G.
That makes life complicated when it comes to altering the wiring.
It would probably be best to buy a "wiring centre" (B&Q or plumbers merchant) and connect everything to that.
Here's the correct wiring diagram.
View media item 70
HI
Not sure if i read that right but the heating live output from the controller seems to be connected to the room stat as expected but terminal 2 of the roomstat appears to be connected to neutral so with the stat in position 2 would be a dead short ?
Or is that stat not actually a 2 way switch ?
Terminal 2 is connected to Neutral but the thermostat switch only connects 1 and 3. The reason for the neutral connection is that the stat shown has an anticipator. This is a resistor between terminals 2 and 3 which warms up when the thermostat is calling for heat. The purpose of this is to reduce the difference between open and closed temperatures on bimetallic thermostats. Modern thermostats rely on solid state devices to measure temperature and do not need a neutral connection.
Don't denigrate your own ability.
You can keep your separate connecting blocks and still get the system working properly. After all, there are only two wires to be added.
Although it looks daunting at first i managed to rewire my system inside a day and that was resiting the controls.
Can you read a circuit diagram and can you use a multimeter ?
Do you feel competent doing electrical work ?
Befor you start though, a couple of points.
What boiler do you have ? There may be a pump overrun timer to contend with.
Have you checked the cylinder stat wiring ? There should be 4 cores, 3 conductors plus earth.
Remember to turn off at the mains befor removing cover.
If ther are then an extra wire to the cylinder stat would not be required.
A problem i some times encounter is that although the system works correctly sometimes 3 core mains is used and the earth gets used as a conductor.
This is both wrong and dangerous and should be rectified.
If it is all ok then all you will need to do is run another cable to connect HW off from the controller to the grey wire connection of the valve.
A couple of photographs may be helpful if you can.
Particularly one of the connector blocks.
so would this be correct -
if i have 3 conductors on the boiler thermostat ( and an earth )
i connect the grey wire to the HW off terminal on the drayton lp522 ??
would this then mean that i have to change the timer to P ( pumped )
would this also mean that if i put CH on, the HW will not automatically come on ?
if i have 3 conductors on the boiler thermostat ( and an earth )
i connect the grey wire to the HW off terminal on the drayton lp522 ??
would this then mean that i have to change the timer to P ( pumped )
would this also mean that if i put CH on, the HW will not automatically come on ?
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