Wiser kit 2 No CH

[Chri$]

Hi, my first post here as a newbie so hopefully I've got this right.

I'm a qualified spark so no issues regarding regs etc.

I've today changed a Drayton Tempus Three to a Drayton wiser kit two.

Wiring at the programmer/time clock exactly the same as the wiser two a simple swap over.

All seemed to work fine until only CH is selected, the CH pump fires up but not the boiler.

Turn the HW on aswell boiler kicks in all works ok.

The previous controller if selecting CH the HW would also automatically be selected too.

The system has boiler on ground floor, central heating tank upstairs, mains cold water fed not gravity from loft.

Tank has two grundfos pumps one pump back and forth the boiler and the other for central heating. On the old controller when selecting CH both pumps would run, when selecting HW only one pump would run.tgere are no two / three way valves on this system

The old stat has been linked out.

Could anyone help me here, as the above if CH switched on it doesn't bring in HW water pump to heat tank so the radiators are flowing cold water until I manually switch on HW.

Any help will be great appreciated

 

[ianmcd]

Ooops not the news you want to hear, but the Drayton wiser is not compatible with your setup, you dont have gravity HW but it is wired as Gravity HW but the wiser doesnt have the Gravity HW facility, if you want to use the wiser, you will have to rig up some kind of relay system

 

[Chri$]

Ianmcd, many thanks for your prompt reply.

understood, so an additional relay to pull in the HW when the CH starts makes sense now, shame they haven't built it in to the controller, but hey ho, I'll do some research today and see if it's better to look for an alternative kit or source and wire in a relay and take a look to see where it can be safely placed. Nothing's easy!..

Also the contactor I assume here now without looking that supplied from CH pump which then switches to turn on HW pump then bringing in the boiler. I haven't looked at the wiring just yet am I not then bypassing the tank stat or is that wired so that it's only used when solely calling for HW?

I guess there could be the use of a three way valve installed into the plumbing so that it was only heating the CH and both could be switched independently then, saving heating the HW tank when only heating needed l'll be using a plumber to that if it's good to go down that road

 

[ianmcd]

I guess there could be the use of a three way valve installed into the plumbing so that it was only heating the CH and both could be switched independently then, saving heating the HW tank when only heating needed l'll be using a plumber to that if it's good to go down that road

you would still need a relay, or even with HW off and CH on both pumps would still operate, if you could fit a Y plan or an S plan and remove one of the pumps, then you could use the wiser