Fused Spur Blows when Heating Switched On !! Water Works OK

[alx]

we did bridge it before (by-passing the 3-way valve), and the boiler and pump all ran fine..

we couldn't find any earth faults on the actuator, but as that was the only part we had removed, assumed it was responsible for the fault..

 

[seco services]

ok.
so your saying it points to the valve.
is all the wiring in the right place ?

 

[alx]

Just trying to find the diagram to check it.. Something is definitely to cock !!

 

[alx]

Just checked the wiring which is all in accordance with the diagram from the installation manual for the boiler.

However, just to spice things up now the fuse blows whenever I switch the spur on.. Got an NIC EIC inspector coming over tomorrow to have a look at it.. Not happy !

 

[sambotc]

If you just replaced the actuator, could it be that the mid positon valve itself is seized causing the actuator to trip the fuse by resistance?

Have you removed the actuator head and tried turning the valve spindle with a spanner to ensure it move's freely?

Just a thought

Sam

 

[JohnD]

and in that case, if you took the actuator off and it was free to turn without load, the controls should work?

Is this one of those actuators that turns a switch on as it moves? so the problem might be that you have connected the switched output wires wrong?

 

[alx]

mid position valve is moving freely.

I have replaced the old actuator, leaving the system setup exactly as it was before when the heating was working. It is still blowing as soon as you switch the spur on. I removed the programmer and it did not blow.

I know everything is connected from the programmer, but I am suspect of whether that is causing me problems.. ?

Is there a way of testing the programmer with it removed from the wall plate ?

Ie. connecting mains power and checking outputs.. ?

 

[alx]

Right then, I have just check continuity on all the feeds from the room stat and the programmer wall plate. All is well apart from the live from the programmer wall plate has no continuity upto the junction box.. (wondering if that has shorted somewhere)?

As for the wiring in the junction box.. This is what I have;

Neutral from programmer -Neutral from Room Stat, Actuator, Pump.

Earths

Live from programmer (which has no continuity) to Live from Actuator, Pump and Black cable from tank stat.

Room stat control to Actuator Brown and white cable.

Room stat live to Heating on

HW on to tank stat live

HW off to Actuator Grey cable + tank stat neutral.

Looks right to me, but if someone could cast an eye over it, it would be appreciated !! Just got to find this short now !!

 

[seco services]

does it blow with the L,N,E to the programmer wired in but not ch,hw,hw off not wired in.

 

[alx]

Hi,

No checked that and the programmer works fine wired upto a plug..

 

[seco services]

have you tried the white from the actuator straight to a live.
not from the programmer/room stat

 

[alx]

on the HSA3 it would be the grey for the switch..

not sure what that would prove though ? could you explain a bit ? did you see my post above about the live feed ?

 

[seco services]

so your live from junction box to programmer is not live ?

 

[alx]

Ignore me, I am a complete idiot.. I was testing the live from the wall plate, which is actually the input from the spur.. It then goes to the boiler before going to the junction box.

The Live supply to the junction box is fine.

But now I am stumped again as everything appears to be wired correctly and still it is blowing fuses like there is a short somewhere...

 

[seco services]

are you changing fuses evertime this blows ?