Replacing a Grasslin T2002

[scorpiouk]

Hi,
Im sure this has been asked many time before, but I just want to be sure before i start..

I want to replace a very old grasslin T2002 on a what I belive is a fully pumped system with a 3 port valve.

My quesiton is around the connections in the current timer..

Currently there are terminals labled as follows and connected as follows:

N ........ L ..... . N ............N
(Black) (Red) (Blue) (empty)

Spare . CH HW
(Earths) (Red) (Yellow)

Im wantingto replace with a Horstmann C17 Timeswitch. 2 channel

I belive the new pins should be:

Pin: Wire:
------------------
Earth - Earth
N - Black
L - Red
4 - CH - (Red)
3 - HW - (Yellow)
3
1

My worry is what I do with the Blue wire currently connected?

Hope someone can help

regards

dis

 

[D_Hailsham]

I want to replace a very old grasslin T2002 on a what I belive is a fully pumped system with a 3 port valve.

Im wanting to replace with a Horstmann C17 Timeswitch. 2 channel

The C17 is a single channel.

 

[scorpiouk]

I want to replace a very old grasslin T2002 on a what I belive is a fully pumped system with a 3 port valve.

Im wanting to replace with a Horstmann C17 Timeswitch. 2 channel

The C17 is a single channel.

Thanks... C27? is that 2 channel?

Its more the wires worring me

 

[D_Hailsham]

Thanks... C27? is that 2 channel?

That's better.

You say you believe it's fully pumped with a mid-position valve. How certain are you? A pic of the valve would help, or the valve model no.

Can you have hot water on, by itself, in the winter, or is it tied to the heating? That is, you can have HW alone in the summer but you must have HW and CH in the winter.

 

[D_Hailsham]

My worry is what I do with the Blue wire currently connected?

I missed this bit.

You need to find the other end and say what it is connected to.

 

[scorpiouk]

My worry is what I do with the Blue wire currently connected?

I missed this bit.

You need to find the other end and say what it is connected to.

Hey,

many thanks for the reply..

The valve is a Honeywell V4073A 3 Port Motorised Valve from screfix

At the moment the Heating and the water are tied together..

This is the reason I want to move to a dual channel system.

Water on constant.... Heating on timed..

Thanks

 

[scorpiouk]

Untitled

• scorpiouk
• 30 Sep 2010
• 1

 

[D_Hailsham]

The valve is a Honeywell V4073A 3 Port Motorised Valve

At the moment the Heating and the water are tied together..

This is the reason I want to move to a dual channel system.

Got that. The C27 will do the trick. The question is will the wiring to the existing timer do the trick? Possibly - it all depends what the mysterious blue wire does. (You need to find out.) For a V4073 to work properly you need a connection from the HW OFF terminal of the C27 (no such terminal on the T2002). This means you need five wires to the C27 (L, N, CH ON, HW ON, HW OFF). You also need three wires connected to the HW cylinder thermostat. Here is the full wiring diagram:

View media item 31288

 

[scorpiouk]

THanks for the reply... I will do my best to check..

Not wanting to confuse, but i have recheked the valve... its at Siemens-CZV322-3-Port-Motorised-Valve?

Are the above comments still valid?

the blue wire.. Looks like its part of a 4 core cable, Yellow, Red, Blue, Earth...

 

[D_Hailsham]

i have rechecked the valve... its at Siemens-CZV322-3-Port-Motorised-Valve?

Are the above comments still valid?

Are you 100% sure it's a CZV322 not a CMV322. If it's definitely a CZV322, then you have a diverter valve, not a mid-position valve and the diagram I posted is not appropriate.

the blue wire.. Looks like its part of a 4 core cable, Yellow, Red, Blue, Earth...

Are the Red and Yellow wires the ones which go to the CH and HW terminals? If so the blue wire probably goes to the room thermostat with the red wire.

 

[scorpiouk]

its this one:

http://www.screwfix.com/prods/45944...ontrols/Siemens-CZV322-3-Port-Motorised-Valve

 

[D_Hailsham]

OK. Can you find the other end of the cable from the valve and tell me how many wires it has and what colours.

 

[scorpiouk]

OK. Can you find the other end of the cable from the valve and tell me how many wires it has and what colours.

Will have a look at the weekend..

Thanks for all the help so far!

 

[D_Hailsham]

Will have a look at the weekend.

OK.

Can you also physically check the valve is a CZV and not a CMV. I cannot locate the CZV322 in Siemens catalogue! If necessary post a pic of the label on the actuator (that's the metal box).

 

[scorpiouk]

Will have a look at the weekend.

OK.

Can you also physically check the valve is a CZV and not a CMV. I cannot locate the CZV322 in Siemens catalogue! If necessary post a pic of the label on the actuator (that's the metal box).

Sorry for the VERY late reply.. hope this still reaches you...

I have take a pic of both ends, in an attempt to trace the plue wire..

Boiler end:

Untitled

• scorpiouk
• 1 Nov 2010
• 1

Thermostat:

Untitled

• scorpiouk
• 1 Nov 2010
• 1

hope this helps..

agian sorry for the late reply.