Danfoss Motorised Valve

[noomsa]

Hi,

I am new to this site and need some help. My boiler is Ideal Classic LXFF FF240 ( don't know if this is the right model no, this is what it says on the boiler) with Danfoss FP715 control system, and a 3 port motorised Valve(matches with the pictures on ur abb. page).

The problem is that hot water is working but central heating is not. Sometimes CH dose work if we move lever to manual position, but again when the timer goes off and turns on, the central heating dose not work. but this turning of lever to manual position don't work every time.

What should be the actual position of lever should it be on auto or manual position, do we have to change any part or the whole of the motorised valve? or there is some other problem plz help!

 

[2face]

by opening it on manual all you are doing is opening the valve and when hot water is requeired it also goes round the heating circuit .. when the hot water is up to temperature it shuts the boiler down .ie: no heating . sound like the motor or micro switch may be faulty ..
remove the head if possible and turn the heating on .. the little motor should be heard and seen to turn on the underside of the valve.
if u r a little clever open the 10 way box in the cupboard ie: near the motorized valve and check the connections in side. when the heating only is on there should be power to the orange wire .if no power to the orange check power to the white etc etc .. no power to the white check power in and out to the room stat .. and so on .

 

[MANDATE]

Try a search for 3 port valves or read my past posts on this subject.
It's almost certain the valve is not being moved across to the CH only position or if it is, the microswitch is not activated/faulty and preventing power getting to the boiler. It needs to do both.
The valve operates in two distinct stages. basically HW only to HW/CH and HW/CH to CH only. You may not always hear the motor movement until you try HW only followed by the others. When you switch off your system the valve stays put, so if the valve was CH only when it went off and you selected CH only, the valve would not move so you would not hear the motor. likewise for the other settings.
If you select HW only, power is removed from the motor and the return spring turns the motor backwards to the start position. You will hear this but what you want to hear is the motor being driven forward from HW only to HW/CH, then try the next stage HW/CH to CH only.
As 2face says motor or microswitch, or a replacement actuator head.
You didn't say if the CH worked (if only for a few minutes)when set to HW/CH. If it does, then room stat ok as it must have turned valve, if not room stat may be at faulty or even timer programmer. So that is the first thing you need to verify.

 

[barryfrance]

I have had exactly the same problem and the fault is due to the microswitches in the motorized valve. They are made by SAIA Burgess type XCG32197 however, I have so far been unable to find a supplier. Can anyone help?
In the meantime I am trawling suppliers e.g Maplin, Farnell, RS to find a suitable alternative.

 

[gas4you]

FFS it's only about £25 for a new 3 port head

 

[barryfrance]

Dave, Many thanks for your response. A new head for the Danfoss motorized valve type HSA3 is £50 + VAT from Plumb Centre - I am not in the trade. A new microswitch is around £1.

 

[MANDATE]

You could try 'cpc' at Preston for microswitches.

 

[mikeup]

Just replaced honfoss actuator and valve . Still no ch when demanded. Valve on manual and hw demanded I get ch until hw thermostat stops.

Why cant I get ch? I am assuming replacement valve ....fiver off ebay ... New... Is working!!!?

 

[45yearsagasman]

.fiver off ebay

That'll be quality then. The low price should tell you something.
This is a 2008 thread!!!
You've either wired it wrong or its got a duff motor.

 

[Norcon]

Danfoss make crappy motorized valves..

 

[ianmcd]

you only get what you pay for but in my opinion Danfoss are not a bad choice

 

[MANDATE]

Reasons for not getting CH only.
(1) no wire/power from programmers HW OFF terminal so valve cannot go beyond mid position.
(2) faulty micro switch in actuator head preventing power reaching motor so valve does not go to CH only position
(3) Valve does move to CH only position but boiler does not light due to faulty contacts on second micro switch
(4) If valve does not move from HW position then faulty motor or supply from room stat
(5) valve spindle stiff

 

[mikeup]

Reasons for not getting CH only.
(1) no wire/power from programmers HW OFF terminal so valve cannot go beyond mid position. ** wiring replaced as per original - all "looks" good?
**
(2) faulty micro switch in actuator head preventing power reaching motor so valve does not go to CH only position ** replaced actuator with new / unused so unlikely micro switch u/s/ **


(3) Valve does move to CH only position but boiler does not light due to faulty contacts on second micro switch ** see above **

(4) If valve does not move from HW position then faulty motor or supply from room stat ** what should happen first - when I demand CH from control box? Boiler does not react. ( i.e. boiler fires up almost instantly when I demand HW ) ...room stat - any way to test? light goes on when turned to minimum and back up **


(5) valve spindle stiff

** Old valve was very stiff - could only just move it with pliers - New valve fitted move easily with just fingers **

thanks for detailed reply / trouble shooting guide!

 

[MANDATE]

Two easy tests.
(1) with both HW and CH turned off, there should be 230v on the terminal holding the grey wire in the terminal box.
This is the power that drives valve/motor from mid position onwards.without it you cant have CH only.
(2) If the room stat is working ok and power is being fed to the valves white wire via the terminal box, then test the terminal holding the white wire.
With CH on and room stat set low (no voltage) then turn room stat up and there should be 230 volts. If not fault at terminal box or room stat.
The valve needs ths 230v on the white wire to drive the motor/valve from rest position to mid position.
Note: Power to operate boiler/pump come from two sources.
When HW is demanded the power goes from programmer to cylinder stat which then feeds the boiler/pump.
So HW only = cylinder stat
HW and CH = cylinder stat
If HW is not involved or has been satisfied cylinder stat does not supply power to boiler/pump.
So CH only = valves orange wire (micro switch triggered during final range)
Of course the 'orange' wire and wire from cylinder stat to boiler will be joined

 

[mikeup]

ok - Not tested yet - still working through the logic.

Neither the valve nor the boiler respond to CH demand

I can force system to give me CH ( rads warm until HW storage stat turns off boiler. ) if I move valve lever manually to HW+CH

ok - thinking on " out loud! "

when CH demanded first valve has to move to CH ( and or HW + CH ) position, and this then mechanically triggers a micro switch to tell boiler to refer to room stat and decide to turn on boiler!! ?

Oh, and to save me googling all night - when using multimeter ( set 500 V ac ) what do I probe with other probe is there a common neutral - yes i'M THAT ignorant ( but not stupid - don't worry - I know the dangers of live AC ( not as bad as DC! :_P )

thanks again for your thoughts

mike