Replace cylinder stat with room stat- is it possibe & ho

[Kwiffboy]

Hi all,

We've recently moved into a "new" propoerty with an indirect vented hw/ch system. It currently has a cylinder stat but no room thermostat. The programmer is a fairly modern Landis & Staeffa (Seimens) RWB9 unit.

Currently I have the CH programmed to run longer than the HW in both the morning and the evening however, the boiler/system switches off as soon as the HW program switches off so the CH does not continue to run & heat the house.

Ideally I would like to install a room thermostat in the hallway (only room/rad we havent fitted a TRV to except the bathroom).

Can I install one in conjunction with the cylinder stat, or is this not possible with an old indirect system?

If not, can I swap out the cylinder stat for a room stat?

I have included a wiring diagram to show how the existing items are wired. Does the wiring seem correct? - I've been told by a friend that had a similar system that the CH should be independantly switched to the HW which would make sense.

I'd like to do it myself if its just a couple of wires as we've blown the budget getting the bloomin thing serviced. If however its a complicated task please advise and we'll get a competent tradesman in when funds allow.

Any answers appreciated in advance.


Cheers,

Matt.

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• Kwiffboy
• 8 Nov 2010
• 1

Untitled

• Kwiffboy
• 8 Nov 2010
• 1

 

[seco services]

as said your ch should still call for heat even when hw satisfied.

yes you can fit a room stat to the system.
but as it is the boiler should still be firing for heating when hw off.

you wiring diagram don't really help. but looking at the ch side looks ok.

what is the white wire from the drayton valve connected to then ??

 

[Kwiffboy]

Hi Seco,

Sorry - my mistake for not thinking of white printing black in CAD!

To confirm the Drayton wiring is (to left side):

black wire to second terminal block,
earth to third terminal block,
white to fifth terminal block,
grey to seventh terminal black

orange to eigth terminal block on the RIGHT side of the diagram.

Cheers!

 

[seco services]

i can sort of work it out now. and wiring looks ok.

on the MA1 is a marker on the side W.M.H.
with heating only calling ie programmer ch on hw off where is the marker pointing to ?

 

[Kwiffboy]

Seco,

I'm at work but think this picture shows it well enough - it appears to be set as in your example. Would you agree?

Untitled

• Kwiffboy
• 8 Nov 2010
• 1

Cheers,

Matt.

 

[seco services]

you need to check when you get home.

but that is in hw position at the moment. not ch.
so when you get home stick the heating on hw off and see what happens.

but providing the hw is calling for heat you do get hot rads until hw gos off ?

have you also got a multi meter ?
itchy feeling but something tells me the grey is dead.

 

[Kwiffboy]

I'll check and run the test you've suggested when I get home.

I do have a mulitmeter but am definately not an electrician - if you can tell me what setting and what I'm looking for I'll probably be able to muddle through it.

I'll update once I've checked.

Cheers,

matt.

 

[seco services]

easier to test as we go.
but put heating on only and that marker should move to the otherside.
test that first.

 

[D_Hailsham]

Currently I have the CH programmed to run longer than the HW in both the morning and the evening however, the boiler/system switches off as soon as the HW program switches off so the CH does not continue to run & heat the house.

Sounds as if your programmer has been set to gravity HW.

SeeRWB 9 Instructions

It needs to be set to 16 mode, not 10 mode.

 

[Kwiffboy]

Hi D_Hailsham,

I've checked the settings and it's definately set to mode 16.

Seco,

I've done as U suggested. With all switched off, the arm appears to be centred. Selecting HW only makes it move slightly to the right (looking at it like in your image). Swiching HW off makes the arm recentre. Selecting CH only does nothing, and the boiler doesn't engage.

Cheers,

matt

 

[seco services]

Seco,

I've done as U suggested. With all switched off, the arm appears to be centred.

centred as in your pic ?

Selecting HW only makes it move slightly to the right (looking at it like in your image).

ok

Swiching HW off makes the arm recentre.

ok

Selecting CH only does nothing, and the boiler doesn't engage.

Cheers,

matt

got your m/meter ?

 

[Kwiffboy]

yep....

 

[seco services]

ch on only hw off at programmer should read 230v on

white
grey
orange

that pic is that your actual valve or one from the net ?

 

[Kwiffboy]

Hi seco,
Sorry for the delay - multimeter packed up!
On CH only I'm getting 247V of the White and grey leads but only 2V off the orange.

The picture IS of my unit, not one from the web.

Any ideas what the fault is?

Cheers,
matt

 

[matt1e]

Hi Matt
yes your mid position valve is knackered (the microswitch inside the actuator isn't making)

as for adding a room stat, I've altered your drawing to show a basic stat you may need more cable cores depending on whitch stat you get

Matt

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