Replacing a Danfoss HPA2 (4 wire??) motorised valve

[hanvyj]

Hi,

Our heating got stuck "on" - the thermostat was off, even switching it to off at the controller stop the heating. Seems this can be one of the motorised valves being stuck open.

This seemed to be the case, I checked the valves and the CH valve was in the manual override position (the little lever all the way to the end and hooked over). Which is a bit odd, not sure how it got into that position. It was working fine until yesterday when I noticed it not turning off - and no one's gone taken the back off the boiler and fiddled with it.

But the valve is slow to return, and seems to be steadily leaking when in the open position, so I'd like to replace it.

I was hoping to throw in a standard 2 way valve like a Drayton https://www.toolstation.com/drayton-2-port-zone-valve/p38135, however it seems all these valves have 5 wires Brown (L), Blue (N), Earth, Grey and Orange.

https://www.draytoncontrols.co.uk/sites/default/files/22mm%20%28I.%20Guide%29.pdf

The "Danfoss" only has 4 wires, Brown (L), Blue (N), Grey and Orange. The wiring diagram is the same, except for the earth:

https://assets.danfoss.com/documents/355624/AN041186451438en-000102.pdf

Does anyone know if it'll be fine as a direct replacement if I just make sure to connect up a new earth?

 

[cross thread]

Base available as a separate item

 

[ianmcd]

just isolate the earth wire it isnt needed

 

[OvertonPlumber]

On the Drayton!! Not so if you go honeywell!

 

[hanvyj]

Happened again. The motor doesn't move the manual override lever, so no idea how it's getting stuck like this:

Base available as a separate item

I hadn't seen you could buy just the body (I knew you could buy just the head, as that seems a common repair!) - not sure it would be worth the cost saving for the peace of mind of just dropping in a whole replacement though. I think they're 10-15 years old, and the head might actually be part of the problem (maybe because it's been leaked on)

On the Drayton!! Not so if you go honeywell!

Honeywell is also 5 wires with a similar schematic showing an earth. Also nearly twice the price! I'm wondering whether it's worth the extra over the Drayton or a replacement Danfoss.

just isolate the earth wire it isnt needed

If it were the "other way around" and I was replacing a 5 wire with a 4 wire I would know there was a "spare" earth I could just isolate. There could just be an isolated earth there though! Need to take the head off to luck.

I was hoping it would limp along until summer when I could take my time (and call a heating engineer if I mess up) but it's only lasted a few days before getting stuck on again.

 

[Exedon]

I've seen this before manual lever latches itself on for no apparent reason.
Though way outnumbered by honeywell valves we probably replace more danfoss than anything else long since stopping fitting them.
We currently fit E P H cheaper than honeywell and 5 year warranty they have a earth connection but you almost certainly have one in the junction box your valve is wired into.