Yet another Denford triac at fault!

**andy_con** · 21-02-2018

Yep sounds like the cylinder is at fault

**m_c** · 21-02-2018

The fact the problem reverses, makes me think it's more likely to be the solenoid failing.

When the air is exhausting, remove the hose from the non-pressurised side of the cylinder (i.e if it's pressured into the spindle, remove the hose at the spindle end). If it's the cylinder that's leaking, then the air will escaping from the cylinder. If it's coming out the hose, or there's no change, then it's likely to be either the solenoid, or something lose/broken near the solenoid (I have seen the pressfit couplings simply fall apart and start leaking with age).
I'm not sure what machine you've got, but if it's a separate control box, the solenoids are all mounted in a box on the rear of the machine. I think if it's a machine with built in control box, then they're in the main control box.

If you do need a cylinder, I should still have a new one kicking around.

**Ade taplin** · 22-02-2018

Hi I had a similar fault on my triac this week where the carousel would only travel 1 way when it should of retracted the solenoid just exhausted air out. I stripped the solenoid and found it was traveling further one way than the other, I figured it to be the internal clear seal was damaged, these have been discontinued so I just fitted a similar sized O ring now all is fine. I figured that the 2 clear seals are there to limit the solenoid piston travel. The cost of a replacement solenoid is getting on for £100. Hope this helps

Ade

**jamesgates1000** · 22-02-2018

I thought it probably would be the solenoid as the cylinder is fairly new. If I take off the pipe at the spindle end, no air escapes from the cylinder and carousel is pushed firmly up to spindle.

I have the machine with the built in control cabinet, solenoids are top right.

Is it this part that would need replacing?

https://uk.rs-online.com/web/p/produ...E&gclsrc=aw.ds

Or this bit...

https://uk.rs-online.com/web/p/produ...E&gclsrc=aw.ds

**m_c** · 22-02-2018

Good question. I never realised these used pilot operated valves, so it could be either part causing the problem.

I'd try swapping the pilot valves (...378 part) around first, as it could be a seal between the pilot valve and 4/2 valve body causing the problem. If the seals are ok, then you can see if the fault moves or stays.