Quick answer on mid position valve fault please

[Sharp Point]

Evening all, I’ve just left my last job of the day and I’m completely knackered. I’ve just been round to a job I did in January ( manual flush radiator on kicrobore) and whilst I was there the old tower mid position valve was making a racket, so the customer asked me to put a new one on( Honeywell)
It’s burnt out( Honeywell), I said I’d try and go back tomorrow to start tracing, but anything spring to mind.... I really haven’t got any spare time( even working Sunday)
One thing that jumped out at me me was the danfoss fp715 screen disappears every other time you press the select button.

Thanks

Y plan fault finding isn’t my forte

 

[townfanjon]

Loose wire somewhere

 

[Sharp Point]

Loose wire somewhere

They had a new Viessmann heat only fitted a few years back, along with a Siemens rdj10( crap) and apparently the tower mid position valve has near enough whined since then.

 

[townfanjon]

Sorry pal , missread I thought the honeywell had burnt out

 

[Sharp Point]

Sorry pal , missread I thought the honeywell had burnt out

It has John, in 3 months

 

[ShaunCorbs]

did you change the whole valve or just the head?

 

[Sharp Point]

did you change the whole valve or just the head?

Whole valve Shaun, the previous tower valve was a complete different entity.

 

[OffshoreGas]

I fitted a new 28mm 2 port Honeywell to heating at home last spring. Found it’s dead already this spring. I’ve just put it down to the quality not being the best. Might be worth double checking the wiring, syncho may have burnt out if it’s constantly getting a demand signal due to a wiring fault.

 

[Sharp Point]

I fitted a new 28mm 2 port Honeywell to heating at home last spring. Found it’s dead already this spring. I’ve just put it down to the quality not being the best. Might be worth double checking the wiring, syncho may have burnt out if it’s constantly getting a demand signal due to a wiring fault.

Yes, there’s something sending voltage to the synchron. I was reading up last night on an intriguing article.

UK DIY FAQ

The synchron is held engaged in mid position in dc and if heating is called ac is sent to the synchron to move it.

The plot thickens! I’ll find the problem, never been defeated yet.

 

[Sharp Point]

Yes, I concur... I think there’s a wiring fault. The multimeter will be coming out, once I’ve spare time

 

[OffshoreGas]

Yes, there’s something sending voltage to the synchron. I was reading up last night on an intriguing article.

UK DIY FAQ

The synchron is held engaged in mid position in dc and if heating is called ac is sent to the synchron to move it.

The plot thickens! I’ll find the problem, never been defeated yet.

May be wrong but my understanding was they only have a single demand.

Voltage on the demand moves the valve to the CH position. No voltage the spring returns to the HW position. Then there are two switched outputs for the valve limits back to the boiler.

 

[Chuck]

Wiring most likely but if not...

Honeywell 3-ports must be on the flow (not return) pipework. I think that getting this wrong will overload the motor.

Is the motor the correct 230-240V variant as opposed to the 220V one sold in other countries?

Is the mechanism operating smoothly when turned manually?

 

[OffshoreGas]

Ignore that, I’ve just bothered to read the manual.

I’m reading that as
CH only:
White - 240v
Grey - 240v

CH + HW
White - 240v
Grey - 0v

HW only
White - 0v
White - 0v

 

[Sharp Point]

Yes, you’ve confirmed what the coloured wires should read. Now what’s going on inside? I’m intrigued now, totally the tinkerer I am

 

[Sharp Point]

Why I haven’t got into the workings of a mid position valve is by now is embarrassing. One of those haven’t got time moments, I’d rather spend my spare time under the bonnet of my toy

Nitrous

 

[OffshoreGas]

Just found this, would have saved working out the crappy diagram they give you. Explains it quite nicely.

 

[Sharp Point]

Yep, seen that a gazillion times. I think you’re missing my point, what’s going on inside? I think it’s fair to say, going by the article I posted early this morning... that there’s more that goes on inside.

 

[Burger]

This any good to you?

 

[Sharp Point]

View attachment 38347

This any good to you?

Cheers, seen that though

 

[Burger]

Cheers, seen that though

Ok, what is it you want to know?

 

[OffshoreGas]

Cheers, seen that though

Which bit is it your not sure about? What the bits in the circuit diagram above are for or what’s actually in the valve body?

 

[Burger]

He’s not been back with the multimeter yet, so maybe it’s a case of wait and see?

Wiring diagrams, check.
Internal operation and resistance values, check.

 

[Sharp Point]

Which bit is it your not sure about? What the bits in the circuit diagram above are for or what’s actually in the valve body?

Until I go back to the job and go over the wiring( re-wire centre) to ascertain proper termination and tightness, there isn’t a pressing issue ....yet. I could be like TFJ says ‘ a loose wire’
If it’s not a loose wire, what is keeping power at the synchron motor to burn it out in 3 months, seems the old tower valve has suffered the same death.. but maybe lasted a lot longer( I dunno, maybe metal gears) where as Honeywell maybe use plastic.

 

[Sharp Point]

Anybody know the resistance across a known decent synchron motor, for reference

 

[Burger]

Anybody know the resistance across a known decent synchron motor, for reference

I haven’t used my free Corgi-direct one yet, I’ll test that when I have a spare minute, if you want?

 

[OffshoreGas]

Anybody know the resistance across a known decent synchron motor, for reference

Just the motor should be 2.2k or there abouts.

 

[Sharp Point]

I haven’t used my free Corgi-direct one yet, I’ll test that when I have a spare minute, if you want?

Lol, yeah I forgot about that..... we’re the fortunate ones

 

[Burger]

Lol, yeah I forgot about that... we’re the fortunate ones

Have you still got yours then?

 

[Sharp Point]

Have you still got yours then?

Nah, I used it a few days after I got it. It’s the same one I usually buy from an independent, but got that fancy corgi sleeve on it