3 port motorised valve should move 90 degrees or 180 degrees?

[me123]

Hi

Following a faulty actuator on a Sunvic 3 port value SDMV2304, I was advised that a compatible replacement actuator is the Danfoss HSA3 (also backed up by http://www.seered.co.uk/sunvic_low_res_catalogue.pdf).

 

However the Danfoss only moves the spindle through 90 degrees (while to move the sunvic valve from HW to CH requires a 180 degrees turn)

• HW only - spindle moves to 9 o clock = Both A and B ports (so I get CH when not desired)
• HW & CH – spindle moves to 7.30 – still A and B ports (ok)
• CH only – spindle moves to 6 o clock – port A only (ok)

 

So I am confused :

a)     Am I unlucky to have picked up a faulty HSA3 – should it move through 180 degrees?

b)     Do I need a different valve body that operates with 90 degrees turn ?

 

Many thanks for any advice…

[dpmiller]

According to the PDF, your Sunvic is motor-on, motor-off, with slipseal, and the image implies it's 90deg from side to side.. Have you got the shaft 180degrees out of position  maybe?

 Or could it be a different valve "under the cover"?

[me123]

Can you explain what you mean by image implies 90 deg side to side? 

The spindle needs to turn 180 degrees (12 o clock to 6 o clock) to go from port A to port B - therefore turning the valve won't help as the actuator still won't rotate the spindle enough to move the valve between A and B. 

 

The Sunvic actuator had already been replaced in the past and an identical valve is still in the old box as only the actuator part was replaced so I am able to see inside the valve and it needs a 180 deg half turn to switch from port A to B. 

 

thanks

 

[dpmiller]

the drawing in the catalogue shows two rectangular rubber plates on a sprung mount, 90deg apart. If the drawing is accurate that means opening one port and closing the other only requires 90deg as it's switching from one plate closed, to the *other* one closed. But I've never been inside one of these so can't confirm.

 

/edit  or is there in fact only one valve plate?

 

@Nickfromwales?

Edited December 31, 2022 by dpmiller

[me123]

Yes that's right just one shoe in the valve, so it needs a half turn. Therefore i don't see how the Danfoss is compatible unless the one I have is faulty..?