replaced Danfoss cp715 with fp715si..still not independent

[fastgreencat]

Hi.advice please.

my parents have had a CP715 for years and have always had to have HW on at same time as CH, which I believe is how the CP715 is meant to work. So I thought a straight replacement with FP715si would allow for independent controls for CH and HW. So I swapped them over, all good, set the programs ..all good. Pressed manual override for HW, boiler fires..all looks good.
Pressed manual override for CH, red light on ..good...but boiler does not fire. Set all thermostat to high to try to force boiler to fire, but no luck. It seems that boiler only kicks in when HW control is on.

So is there something more to it than just replacing CP715 with FP715si ?

thanks in advance
Rob

 

[gas112]

Set the jumpers on back of clock from 10 prog to 16 to get independent switching.

but you should either have 2 two port motorised valves or 1 3 port mid position .
If old gravity system it is working how it should be

 

[fastgreencat]

thanks,
On back of fp715si there seem to be 4 jumpers...

1. unused ?
2. gravity or pumped
3. 5+2 or 7/24
4. 7 day or 24 hour.

How should these be set ?

Will need to check at parents for type of pump. Will this tell me if gravity or pumped ?

 

[gas4you]

2 should be set for pumped.

One assumes it is a fully pumped system though and not gravity primary?

 

[fastgreencat]

thanks,
will check tomorrow.. How will I know by looking if pumped or gravity ?

the cp715 that is currently there has it's jumper set to pumped.

 

[DP]

OP, your system does NOT allow the system to run the way you are proposing. CP programmer also allows one or the other channel to be active if system allows which yours does not. FP is a full programmer that allows independent switching whereas CP has common time base for the two channels.

Plumbing alterations will give you the facility you are after.

 

[fastgreencat]

ah ok thanks.
So swapping from cp715 to FP715 is not enough ? Also requires plumbing changes then ?
thanks