MP valve in mid postion with HW Only on

[daveywavey2]

Hi all,

I had my boiler and tank replaced last year but since turning off the central heating this year, we noticed the radiators were still getting hot. I thought it might be the MP valve as when I disconnected the valve electrically - the rads still heated up so the valve was passing.

I just replaced the old Randall wiring centre with a new honeywell style one suitable for the Sundial Y Plan. I removed the appropriate links and connected everything as per colours indicated and double checked with the honeywell wiring diagram.

I currently am only using hot water so have disconnected the existing MP valve electrically and connected a new one electrically but not physically so I can watch the valve move before fitting to ensure its doing what it should - well its not!!!!

- When CH is selected, the valve moves to CH only and stays there regardless of whether the thermostat is activated or not
- When HW is selected, the valve also moves to CH only but when cylinder stat setting is increased - to demand more heat, it switches to the mid position!
- When CH and HW are selected, it sits in the mid position
- When both CH and HW are turned off, the valve goes to CH only - but this is because it always ends in the mid position and is driven further as normal

Pump/boiler start up correctly and cut in and out when the appropriate thermostat is activated

Any help would be really appreciated - stayed up till 2am looking at this yest!!!


Equipment fitted is:

Worcester greenstar ri boiler (1yr old)
Danfoss HSA3 MP Valve (new)
Drayton lifestyle LP522 Pogrammmer (1 yr old
Honywell wiring centre (new)
Honeywell cylinderstat and roomstat (1 yr old)
Grundfoss pump (1 yr old)

 

[seco services]

what don't you think is right ?

 

[Hugh Jaleak]

Sounds to me its doing as it should. Acid test is to fill the system and run it, then check the heated water from the boiler goes where its supposed to as regards programmer and stat settings.

 

[doitall]

Sounds to me like the valve is the wrong way round

Does Port B go to the cylinder.

 

[daveywavey2]

No - the ports are correct. I havent actually fitted the valve yet- its just connected electrically. So i can physically see the spindle position at the minute.

The problem is that when hw only is chosen, the hw port closes and ch opens-same as when the ch only is selected.

 

[doitall]

No - the ports are correct. I havent actually fitted the valve yet- its just connected electrically. So i can physically see the spindle position at the minute.

The problem is that when hw only is chosen, the hw port closes and ch opens-same as when the ch only is selected.

Then you've wired it wrong.

 

[seco services]

sounds like hw/ch are both wired to the white wire

 

[daveywavey2]

sounds like hw/ch are both wired to the white wire

I have no white wire on the new valve- just red, blue, grey and brown/white. The brown/white is connected into the brown terminal on the wiring centre. Tried it in the white but then nothing happened.

 

[davebgas]

Have you bought the correct actuator for a mid position then??

 

[Agile]

Shouldn't the valve have an orange wire?

I suppose this was a "bargain" on Ebay because its a "special" which is usless in most situations.

Tony

 

[davebgas]

I was thinking it had too few wires! Sure this is a div valve actuator not a MP as required

 

[doitall]

240v on the orange only is HWS.

240v on the brown and orange mid poition.

240v on the brown, grey and orange HTG

Brown/white htg call.

Orange HWS call

Grey HWS sat.

 

[Agile]

I have no white wire on the new valve- just red, blue, grey and brown/white. The brown/white is connected into the brown terminal on the wiring centre. Tried it in the white but then nothing happened.

He does not seem to have an orange wire John !

I am guessing its a three port, two position valve!

Blue and red for motor ( will read about 2.2 K resistance ? ) and grey and brown/white will be the switch, o/c when motor not powered and spring returned to rest position and joined when motor is powered and has driven the valve to the powered position.

Tony

 

[doitall]

No power and port B is open

240v on the brown mid position.

240v brown and grey port A open

But what controls the boiler/pump I've no idea, perhaps it's done from the programmer

 

[doitall]

All the HSA actuators I've found have an orange wire.