Danfoss 103 --> oil boiler

[bri70123]

hi

Can anyone tell me if my danfoss switch is wired up correctly, its connected to a conventional oil boiler, no room stat, when the timer clicks off the central heating pump continues running forever unless the mains is switched off, as thats what its effectively connected directly to, should its LIVE be connected to T1... and does the stat wiring look right (neutral into T1).

thanks

 

[stem]

The Danfoss 103 is a single channel timeswitch, so the heating and hot water functions can't be separated to work separately. Therefore usually the pump and the boiler are connected to terminal 1 and both go 'on' and 'off' together. How yours is wired, and as you have noticed the pump will run continually.

However, some boilers require that the pump continue to run for a short while after the boiler goes off to get rid of residual heat. Many gas boilers have this facility, but I'm not sure about oil boilers. Your boiler installation manual will tell you if there is a 'pump overrun' required.

I have seen an installation where a boiler that needed a pump overrun had replaced one that didn't, so it had been wired like yours so that the pump didn't go off when the boiler did. Thus providing an extremely long 'overrun'.

 

[bri70123]

The Danfoss 103 is a single channel timeswitch, so the heating and hot water functions can't be separated to work separately.

I was going to replace it with a 103e7 anyway as the manual one ticks loudly...

The CH pump has a manual on off switch below the timer (just didnt want to complicate the drawing), is that so i can heat water without having the CH running.

thanks

 

[stem]

Probably; and if the boiler works OK when just heating hot water (ie when the pump is switched off) then your boiler is working without a pump overrun.

 

[Mike2007]

Thermostats would benefit your system greatly.

 

[bri70123]

Thermostats would benefit your system greatly.

original house is detached 1825 solid 2ft stone walls, 2 storey extension more recent with cavity so would TRVs in each room not give more balanced temp?

 

[Terrywookfit]

You may as well fit a 102 twin channel.... same backplate and alter a wire.

Blue wires are not always neutrals in Htg systems

 

[Terrywookfit]

original house is detached 1825 solid 2ft stone walls, 2 storey extension more recent with cavity so would TRVs in each room not give more balanced temp?

Fit both....A trv does not turn pump off when temp is reached.

 

[bri70123]

thanks all for replies, ill keep an eye out for a 102e* & look into fitting a stat somewhere...


Brian

 

[bri70123]

hi

I fitted a 102E5, connected CH pump to term 2, this alowed the pump to be switched on / off via the CH-HW /HW switch. There are four pipes going to / from my boiler, 2 15mm for the radiators and two 35 mm for the water tank.

First day i tried it on HW only and only one of the 35mm got hot, and hour later both 35mm hot, the two smaller pipes remained cold, great. But now whenever it try it, the two smaller pipes (which feed the radiators upstairs got hot only, the 35mm ones remained cold, so my upstairs radiators heated up (which went down great at bedtime it was 28 outside that day) but not the HW. do i need to fit an actuator valve to the CH to stop gravity taking the heat upstairs and instead to the hw tank?

thanks

 

[Terrywookfit]

which boiler do you have. 35 mm circs are rarely seen.
a sketch of pipe layout would help