Fitting new 5111603 PCB to suprima 50

[MANDATE]

Just thinking about the room stat, it may have been by-passed by incorrect wiring and not having the control.
This would mean the 'white' would always be live and valve stays at M and never goes to W. That is except when CH is off.
(seems to fit in with grindstones results).

 

[Grindstone]

Got back too late tonight to ask the neigbour to come out now, the room thermostat only has two wires, I'll switch them tomorrow and see if that presents any change following the same test as before.

Hopefully my neighbour will be home early armed with a multi metre and a need for a cold beer

Can't thank you guys enough for all the help, it has been deeply frustrating getting plumbers out to watch them scratch their heads and leave, if you're ever near Oldham, or you fancy a trip out on a RIB and you are near the coast let me know and I'll give you my contact details

Neil

 

[MANDATE]

Got back too late tonight to ask the neigbour to come out now, the room thermostat only has two wires, I'll switch them tomorrow and see if that presents any change following the same test as before.

I don't see how switching the wires will achieve anything.

But it costs nothing to examine the wiring and verify the wires are to the correct terminals and it is switching on (and not off) according to demand.
I would get your sparky to check it.
I can understand your plumbers scratching their heads, not only is it difficult to understand, its near impossible to explain it all in writing. very similar to 'chess'. And it doesn't help if there are two problems to get your head round.

 

[Grindstone]

Folks

Problem is now solved!

I worked from home today which allowed me time to tinker. The actuator head I bought was the ACL drayton MA1, which is the replacement part for the ACL Drayton 679H340-3OLO valve, although I only bought the head and not the full valve in the (mistaken) belief that I could change the heads.

You can't, the old valve head can't be replaced with this you need the entire valve.

But looking at it closely it looked like the screws that held the micro switches in place were in the MA1 valve, but not used as it is a snap fit.

So I turned of the power and:

Took the motor of the old valve, (two screws either side of the motor)
Disconnected the earth
Unscrewed the two screws through the micro switches that hold the circuit board in place and pulled the lot off.

Looks exactly the same.

So I dis connected the wires from the block connectors at the other end, and the fit the new motor off the MA1 valve onto the backing plate of the old valve, (so no gas work, wet work, plumbing etc.) screws line up exactly, refit the earth.

Then used the old screws that went through the micro switches on the old part, fit exactly, (small point as the new circuit board is a snap fit I had to cut the back part of the board down) and screwed it all up.

Refit all the wires into the same block connectors the old ones were in, then went back down stairs and flicked the power back on.

RESULT!

Everything is now working as it should be, which I guess means it was the micro switch, it does look dirty etc. and I have a new motor as well.

Whole job took about 30 mins max.

Can't than you enough for all the help

Best regards and a warm and Merry Xmas

Neil

 

[matt1e]

well done mandate though I would still check that your room stat is working as it should as even a knackerd valve head doesnt explain this

CH HW on Cyl stat demand room stat no demand switch M boiler on

just select central heating only on the time clock and make sure
room stat calling = valve at H and boiler on
room stat satisfied = valve still at H and boiler off

if no difference room stat caput = possible shorted out relay in stat{you can usually hear it click if its ok)

cheers
matt

 

[MANDATE]

Hi Neil! Glad to hear of your achievement. I'll bet your pleased!
There was never a doubt about the micro switch not working.
So that just leaves
grindstone wrote:

CH HW on Cyl stat demand room stat no demand switch M boiler on

As you know with room stat 'no demand' and 'demand on cylinder stat, valve should drop back to Water, not Middle.
If it still stays at middle, you may still have a problem.

 

[MANDATE]

 

[Grindstone]

I switched the wires round on the room stat, I suspect they were back to front, but as I did this before changing the actuater etc, I'm not sure if it did make the difference.

Still didn't make everything work at the point I changed the room stat, so it was deffo the micro switch.

After I fitted it I checked the lot before posting, so

No Power at all, switch at W

CH on on its own and demand at room stat, switch at H
CH on on its own no demand at room stat switch still at H

HW on on its own, Cyl stat demand switch as W

CH and HW on demand from both stats switch midway

So looks to be totally fixed. If it plays up I'll post back on this thread, but as it is all looking fine.

 

[matt1e]

CH on on its own and demand at room stat, switch at H
CH on on its own no demand at room stat switch still at H

yes but is the boiler firing/not firing respectivly

matt

 

[Grindstone]

It is It is, all boiler fires when it should goes out when it should, I'll check the switch is moving to all areas properly later on, but as it stands at the moment CH is on constant at the clock and I can fire the boiler and switch it off by increasing and decreasing the thermostat!

Its like a new house

 

[gavinda]

well done. it could well have been the pcb in the valve. we'll never know. but great result all the same.

 

[MANDATE]

it could well have been the pcb in the valve.

The problem was the boiler not lighting when in the CH position.
The pcb is not related to this function. Its purpose is to generate a 'modified' voltage to hold valve at mid position. Not only that, but the triggering of the second micro switch cuts power from the pcb to divert it to the 'orange' wire.
So how is the pcb involved, when its not active? If you can explain it, your hired!

 

[Grindstone]

As you know with room stat 'no demand' and 'demand on cylinder stat, valve should drop back to Water, not Middle.
If it still stays at middle, you may still have a problem.

Switch is moving though all the stages at the appropriate points. From re reading the posts I think micro switch 2 was the issue.

looking back when the CH was on and there was demand at the room stat, the switch did move to H, but nothing happened at the boiler end, so I assume micro switch 2 should have sent a signal to the boiler to light, which didn't happen. In turn when the switch was in mid position due to HW demand, I guess the same switch should have ben telling the boiler when the room stat was satisfied.

All suposition on my part as I'm a project manager/system analyst by trade, so this just makes logical sense to me.

Further to this I'm guessing that when I has the original short to the upstairs light it tripped the whole fuse box due to a bad neutral, I think it must have tracked back and knocked the micro switch out then.

Anyway, top forum with a wealth of advice couldn't recommend it or you guys enough. Once again thanks very much and hope you have a Merry Xmas and a top New Year.

All the best

Neil

 

[matt1e]

gavinda wrote

it could well have been the pcb in the valve

mandate wrote

The problem was the boiler not lighting when in the CH position.
The pcb is not related to this function. Its purpose is to generate a 'modified' voltage to hold valve at mid position. Not only that, but the triggering of the second micro switch cuts power from the pcb to divert it to the 'orange' wire.
So how is the pcb involved, when its not active? If you can explain it, your hired!

I thought the problem was

the problem is that the water must be on to make the heating come on! The thermostat works to send a demand for heat, but will not turn the heating off, it just gets hotter and hotter until I turn the water off, then the boiler goes off

which as I said earlier the statement up to the explanation mark is indicative of a dodgy microswitch second part not
any way problem solved and as replacement valve cured it we have to assume there was also an internal short to the white on the pcb
if this information is correct

CH HW on Cyl stat demand room stat no demand switch M boiler on

then the power to make the valve drive to midway has to be originating from the orange but if the orange is shorted with the white then of course

CH only Cyl stat demand room stat demand switch H boiler off

doesn't seem to make sense either as if the orange and white were shorted the boiler would fire but if you look at this again the only explanation is that there is a short on the legs of the bottom microswitch with the common (to white) being open circuit

I've never come across this one before but in the field I would measured 230 on grey and white and found no volts on orange and changed the valve long before I noticed that one! anyway job sorted have a warm comfortable crimbo
matt