How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Plumberpro Your Own Question
Plumberpro, Plumber
Category: Plumbing
Satisfied Customers: 634
Experience:  Heating and plumbing answers. 20 years experience
Type Your Plumbing Question Here...
Plumberpro is online now

I have a Drayton controller water and central heating,

Customer Question

I have a Drayton controller for hot water and central heating, it was malfunctioning. By mistake I disconnected the wires from the back plate and need to refit them. I have six wires, the mains cable is identified and OK (I checked it with a test meter).
Can you give me clues as to where the other four wires should be connected to make the system function?
Submitted: 2 years ago.
Category: Plumbing
Expert:  Plumberpro replied 2 years ago.
Hi . do you have two motorised valves , one for hot water and one for heating? Or one three port?
Customer: replied 2 years ago.

The controller is running a Baxi Bermuda, so, as I understand, it doesn't have motorised valves.

Further thoughts, the 1.5mm cable must go to the pump situated under the floor. I don't understand the other cable, being a Baxi Bermuda there is a pilot light, this is working. Does the other cable just go to the Piezzo ignition or what?

The controller must interact to start the system, whether it's just to heat water to go to the storage tank upstairs by gravity or start the pump to drive the heating. I know not all of the four 'output' points on the controller back plate are used with this system, so I suppose the principal question is how do I wire the pump into the controller?

Does this help?

I shall be online again in the morning, I should have a Drayton LP522 controller delivered tomorrow.

Expert:  Plumberpro replied 2 years ago.
OK boiler has earth ,neutral , permanent live and switched live. There is no pump live from the the cable out from boiler is probably to the controller.
so hot water on from programmer , out to boiler switched live. Heating on , out to boiler switched live and pump live.. So the six wires from the programmer, should be live , neutral, earth. Then two wires back to boiler switched live , and another wire to the pump from heating on
Customer: replied 2 years ago.

Thank-you, I think I understand. I'm waiting for the new Drayton controller to arrive and will do my best to interpret what you have told me when I install it.

So I ignore HW and CH 'off', and put the wire from the boiler to common live and the HW on, and the pump also to common live and CH on.

Let me know if I've misunderstood.

I will come back to you whatever the results.

Regards, David.

Expert:  Plumberpro replied 2 years ago.
Hi, yes the hot water off is used if you have a tree port motorised valve to pull the motor right over to heating . heating off isn't used.
Yes that's right, common live to boiler permanent live, hot water on to boiler switched live . heating on to pump and boiler switched live.
Customer: replied 2 years ago.

OK, I've followed what I think you said, but the system with the Drayton LP522 hasn't fired up.

Looking at the connection instructions that came with it, it shows the back plate with four connections on N,L 3 and 4, this, I think is what you said.

Now the difficulty. It shows a junction box LWC3, obviously I'm not using this, I don't have one. It shows 3 going to position 7 and this goes to the boiler live. I follow that.

Now the pump, (that is the chart showing the pump) I shows the L going to 5 on the junction box but not where 5 goes to the controller. It shows N going to the common N, no problem, but what goes to 5 in the junction box? Should they have indicated 4 on the backplate going to 5 in the junction box not 4? This seems to make sense to me.

I can obviously create this junction box and put it in a small ABS enclosure, I imagine you would suggest this.

The chart shows all the Ns together rather than the Ls as I interpreted you advised, so do I just need to change this round and connect it as they show but using terminal 5 in my created box as the connecting point for the pump live?

Regards, David.

Expert:  Plumberpro replied 2 years ago.

Hi , if you haven't got this junction box I would just ignore it. So you have live and neutral . 3 is HW on and 4 is heating on . 3 and 4 will both run to boiler switched live , but 4 will also run to pump live. Do you have power to the display? When you connect live and neutral ?

Customer: replied 2 years ago.

Yes, I have power to the system and the boiler is firing up properly, so that bit is correct, the gravity feed water is heating properly. The heating side isn't working although I have checked the wiring carefully. It is all set up as shown on the leaflet with the controller.

Perhaps the pump itself has failed, I'm thinking about connecting the cabling up directly to the power to see if it will start up, if it doesn't then I will have to get a plumber in. Getting to the pump isn't easy, the people who installed it years ago put it in a difficult place under our floor.

Expert:  Plumberpro replied 2 years ago.
Does the boiler fire when you put the heating on?
Expert:  Plumberpro replied 2 years ago.
Hi , how did you get on ? Would you plase mind rating my answers , thgankjs
Customer: replied 2 years ago.

My problem has been resolved, it was the pump. It had failed and was short circuiting. A replacement has now been installed and the system is running properly again.

Enquiry closed!

Expert:  Plumberpro replied 2 years ago.
OK , surprised it didn't blow the fuse . check it has a 5 amp Max.
Customer: replied 2 years ago.

The 3 amp fuse was blowing, I thought it a problem with the existing controller or its wiring, that's why I got into trouble in the first place!

It didn't blow the fuse when I set up the wiring as I'd put the wires for the pump and the wires for the boiler in the reverse places, and it was when I could see the pump after taking up the floorboards I realised this, I changed the wires over and the fuse did blow again.

New pump fitted and the system works properly.