Replacing programmer Honeywell ST699B with Grasslin QE2

[smipx013]

Hi,

I have a fully pumped system at the moment with a honeywell ST699B programmer. I don't like this programmer as I feel it is wasteful as you can only have two switched programs per day and it has no boost +1 hour button.

I used the QE2 at my last place and got on with it well.

I have checked compatability and the Grasslin site says:

Towechron: E N L 4 3 2 1
ST 699 E N L 3 6 7 L-5-8

I can see that in the pic below my L,5 & 8 are linked. All good.

larger image: http://imgur.com/KBj4Mq3

Couple of questions.

1.Can I in any way use the existing backplate or do I have to unwire the whole thing and then attach the QE2 backplate to the wall

2. I have no wire 7 (which I believe is correct for S layout) so can I just ignore the 1==>7 above

Any other advice gratefully received.

Cheers,

Paul

 

[Whitespirit66]

I think you will have to change the backplate, but the wiring is simpler for the Grasslin. You don't need link wires for L, 5 and 8.

Wire as follows -

HONEYWELL>>>>>>>>>>GRASSLIN
L>>>>>>>>>>>>>>>>>>>>L
N>>>>>>>>>>>>>>>>>>>>N
3>>>>>>>>>>>>>>>>>>>>4
6>>>>>>>>>>>>>>>>>>>>3

That's it. Just remember to select 'fully pumped' on the switch on back of unit.

 

[smipx013]

Nice one. That was what I was hoping.....

Thanks
Paul

 

[smipx013]

Okay so heres the rub.....

got the QE2 off ebay (2nd hand) and was promised its working just fine.

• 
  Slid the switch at back fully to the right (for fully pumped system)
  Installed it all
  turned it on
  pressed the reset
  set the day and time
  slid to "run built-in program"
  advanced the heating and the water to "const"
  turned the room stat up to 30 (heard click)
  turned the cylinder stat way up to 90 (heard click)

The heating works - the 2 port valve actuates when demand is satisfied
light is red indicating its on
There are volts on QE2 wire 4 when demand is there (as I would expect)

The water does not work - the 2 port valve is not actuating
Light is red indicating its on
There are no volts on QE2 wire 3 when there should be demand (I would expect volts)


Thinking I had messed up I reverse wired the old honeywell back and all is working as expected.


Do you think the QE2 is a duff unit? Tried the reset procedure (and boiler reset and room start reset) a few times (they all have buttons to reset).

I suspect the relay for the HW is duff. I may try to reverse 4 & 3 on the QE2 tomorrow to see if the water then works and the heating is broken. If it is then I think its definately a duff QE2.

What do you think?

Cheers,
Paul

 

[Whitespirit66]

If you have power to the QE2, and HW selected, there should be 230v at terminal 3. If not, without doubt a faulty programmer.