Boulter Buderus Combi boiler setup question?

[uptown47]

Hi,

I have a Buderus 500-24/C condensing boiler.

It has a Boulter Buderus Modulink 250 RF wireless thermostat / programmer connected to it on to the terminals marked "Room Thermostat".

I want to use a different programmer (a Potterton EP 5002) because I want to be able to set different heating times per day, rather than just one set of times that is repeated all through the week and on weekends.

I've wired the Potterton Programmer to the connection inside the boiler marker "Programmer 230V". I'm sending Live and Neutral out to the Programmer and I'm receiving "Live Return" back.

Unfortunately, even though 240Vac is going out to the programmer, when the programmer is on I'm only getting 40Vac between the Live Return and Neutral.

I'm presuming this should be 240V correct?

Here's the wiring diagram on the back of the Potterton.

Untitled

• uptown47
• 11 May 2012
• 1

I've connected the Live and Neutral to the L and N (obviously).

I've linked out pins 2 and 5 (is correct or not)?

And I've wired the Live Return to pin 4.

Could someone just make sure this is correct for me.

Any thought on this would be most appreciated.

Cheers

John

 

[Agile]

I would expect you need to link the second connection marked "L" to the one marked "5".

But I dont normally give advice on wiring because its so simple for anyone with the appropriate skills that I would not expect they would need to ask.

I take no responsibility for any damage you do by your attempts at wiring!

It surprises me that anyone else gives advice on wiring either although most hide their true identity.

Tony

 

[uptown47]

Hi Tony,

Thanks for the advice Tony.

I did consider that but didn't want to do it without some confirmation. It looks like anything on pin 5 will be passed through to pin 4 when the programmer comes on but I wasn't sure.

I didn't know whether I should be wiring my 2-wire thermostat into the programmer somewhere or maybe there's some other configuration that I don't know about.

Anyone got first hand knowledge of this??

Cheers

John

 

[Agile]

This all assumes that your boiler takes a 230 vac call for heat. Most do but a few dont! Some like the intergas can take low voltage 24 v or 230 vac although on different terminals to give the installer flexibility.

Your two wire stat can go in series between terminal "4" and the boiler call for heat.

Tony

 

[uptown47]

This all assumes that your boiler takes a 230 vac call for heat. Most do but a few dont! Some like the intergas can take low voltage 24 v or 230 vac although on different terminals to give the installer flexibility.

Yep, I'm sure mine does. The terminals are L, N, L(ret). i.e. Live, Neutral and Live return.

I'm just a bit worried about wiring a Live to either pin 2 or 5 just in case it knackers something up...

I'll continue to search for a manual for the EP 5002 and see what that says.

Thanks again for your continued help.

Cheers

John

 

[simond]

Link L to 5 on this old fashioned progammer if you want it to work.

Do not connect anything to pin 2. Live out from the programmer is on pin 4 - so you got that right.

As Tony says, some Buderus models may use low volt controls so it is the boiler manual you need, not the programmer one.

Incidentally, you'd have been much better replacing the room stat with a modern progrsmmable 7 day unit like the Honeywell CMT927. The timer you are fitting is rather pointless, we'd just have fitted the CMT927, does more, only one box.