sunvic upgrade ch comes on with hw

[jontee]

Following upgrading the programmer from a Sunvic 207xl to a Sunvic 207xls the HW no longer runs independently to CH. Following the upgrade; selecting HW only results in the radiators becoming heated. It was noted that backplate configuration was N/ L/ HWoff/ CHoff/ HWon/ CHon, (the backplates are identical). However the dip switch settings were changed from: 2 on/2 off/pumped, 24Hr to: 3 on/3 off/pumped, 5/2 day. The system uses a 3 port sprug motorized valve. Why am I no longer able to run HW independently from CH ? Any advice would greatly be appreciated.

 

[Boilerman2]

You need to go back to basics, this fault is either:
1) something you have done whilst changing the programmer
2) A totaly new fault has occured possibly the motorised valve.

Try turning the Room stat (if you have one) right DOWN then select HW only, does the Heating come on? if so probably cause 2 above
If the Rads remain Cold, have a look at what you have done at the programmer

Good Luck!

 

[jontee]

Unfortunately, even with room stat turned right down, selecting HW only results in the radiators heating.

 

[jontee]

Just thought its worth mentioning that I found it unusual that there is no connection to the back plate terminal for CH off (terminal 2). i.e. Only 5 cables present/connected, not 6 as per wiring diagram . It’s not a particularly old system as the house is only 10 years old. Regards.

 

[twgas]

did you swap the back-plates or keep the old one connected?

 

[jontee]

I used the original one and kept the new one as a spare. Regards

 

[twgas]

Then there should be no diference in the operation, did it work properly before you "played".

 

[picasso]

there is an option for gravity or 2 port or 3 port, I cant find the instructions on line so cant help with how to select the 3 port option, but its likely to be this.

 

[jontee]

re: "played"

Yes it did, replaced as early signs of contact failure were observed, contact bounce (chatter), that’s why im bamboozled. Planning to try a replacement 207xls prior to condemning the 3 way valve.

 

[jontee]

there is an option for gravity or 2 port or 3 port, I cant find the instructions on line so cant help with how to select the 3 port option, but its likely to be this.

Gravity or Pumped can be selected but no option regarding port.
, dip switches identical to 207xl, instructions for which can be found at http://www.sunvic.co.uk/documentation/Programmer_Select_207.pdf

 

[picasso]

yea your right I misread the instructions.

 

[jontee]

Thanks for all your input, it looks as if Boilerman2 was right “2) A totaly new fault has occurred possibly the motorized valve.”.

Taking the powerhead off and manually moving the spindle cures the problem ie. HW only is delivered.

New powerhead in place and all is well. Many thanks.

 

[Boilerman2]

I Thank-you!!!!!