H/W and H/W with C/H together but NO C/H ON IT'S OWN - HELP!

[Wildeman]

The boiler and pump are indeed connected to the orange wire.

As I mentioned a qualified electrician has had a look and traced/tested all the wiring and it is as per Y-Plan.

I will bleed everything again, am I right to assume that if there was no return on the heating side there would be no heating full stop?

I will get some photos for you of the piping that I you can see, I cannot see any bypass

 

[Wildeman]

Photos as requested Doitall - hope you can see the problem from them!!

View media item 15438 View media item 15439 View media item 15440 View media item 15441 View media item 15442 View media item 15443 View media item 15444

 

[doitall]

In the 3rd pic you have mark the expansion going over the header tank and the open vent the wrong way round.

Please confirm.

Whats in the loft, are there any air vents for example

 

[MANDATE]

I have experienced a similar type problem and it can get confusing until the valves operation is fully understood.
Assume the valve is in the rest position HW only. The valve has to move over to mid position and from there it has to move to CH only position.
The room stat provides power to 'white' wire. Within the valve it divides and feeds microswitches (1) and (2).
The feed through (1) drives the motor until it is activated at mid point. This cuts off the white supply to motor and picks up another supply. This other supply is provided from the programmer (HW OFF terminal) and feeds the 'grey' wire which continues to drive the motor to the CH only position where it is held against a stop.
There is also an alternative supply to the 'grey' from the satisfied terminal of the cylinder stat used when HW is ON (no need to consider this when problem is CH only)
So microswitch (1) has two power input sources feeding it, white for first half and grey for last half. There is just the one output to the motor.

Microswitch (2) is wired different, there is only one input but two outputs (not at the same time of course).
The divided white is the input and the initial output is fed to a pcb to supply a modified voltage to hold valve at mid point (not related to CH only problem)
Now the second output from this microswitch is the 'orange' wire.

This second microswitch is triggered when the valve moves beyond mid point, so it stop feeding the pcb (no longer required)and delivers 240 volts out though the 'orange'.

If this microswitch has dirty or burned contacts it can stop the boiler and pump from operating when in CH only mode.
It does not affect the other modes because HW is invovled and the cylinder porovides the power to run pump and boiler.
Of course if you have 240 volts on 'orange' when HW is off then valve is not the cause .

 

[doitall]

Very good Mandate, nearly but not quite right

 

[Homesafe]

I have experienced a similar type problem and it can get confusing until the valves operation is fully understood.
Assume the valve is in the rest position HW only. The valve has to move over to mid position and from there it has to move to CH only position.
The room stat provides power to 'white' wire. Within the valve it divides and feeds microswitches (1) and (2).
The feed through (1) drives the motor until it is activated at mid point. This cuts off the white supply to motor and picks up another supply. This other supply is provided from the programmer (HW OFF terminal) and feeds the 'grey' wire which continues to drive the motor to the CH only position where it is held against a stop.
There is also an alternative supply to the 'grey' from the satisfied terminal of the cylinder stat used when HW is ON (no need to consider this when problem is CH only)
So microswitch (1) has two power input sources feeding it, white for first half and grey for last half. There is just the one output to the motor.

Microswitch (2) is wired different, there is only one input but two outputs (not at the same time of course).
The divided white is the input and the initial output is fed to a pcb to supply a modified voltage to hold valve at mid point (not related to CH only problem)
Now the second output from this microswitch is the 'orange' wire.

This second microswitch is triggered when the valve moves beyond mid point, so it stop feeding the pcb (no longer required)and delivers 240 volts out though the 'orange'.

If this microswitch has dirty or burned contacts it can stop the boiler and pump from operating when in CH only mode.
It does not affect the other modes because HW is invovled and the cylinder porovides the power to run pump and boiler.
Of course if you have 240 volts on 'orange' when HW is off then valve is not the cause .

how did you come accros this info.??

it would be good to know , but DIA say's it's not quite right

 

[MANDATE]

Hi newgas! I gathered the information about three years ago, mostly from others on this forum. I also stripped a faulty actuator down to examine the microswitches (thought to be at fault) and verify the method of working. After repair I bench tested it using lamp to represent boiler and pump and switches to represent room stat and cylinder stat.
Don't know of anything incorrect in my (part) description,

Come on Doitall! If its 'not quite right' how about explaining whats wrong.

 

[Homesafe]

Hi newgas! I gathered the information about three years ago, mostly from others on this forum. I also stripped a faulty actuator down to examine the microswitches (thought to be at fault) and verify the method of working. After repair I bench tested it using lamp to represent boiler and pump and switches to represent room stat and cylinder stat.
Don't know of anything incorrect in my (part) description,

Come on Doitall! If its 'not quite right' how about explaining whats wrong.

aaahhh, you had a, what's the word now ,ChrisR uses it doodle or something ..

that's one good way of finding info. about things

 

[doitall]

Hi newgas! I gathered the information about three years ago, mostly from others on this forum. I also stripped a faulty actuator down to examine the microswitches (thought to be at fault) and verify the method of working. After repair I bench tested it using lamp to represent boiler and pump and switches to represent room stat and cylinder stat.
Don't know of anything incorrect in my (part) description,

Come on Doitall! If its 'not quite right' how about explaining whats wrong.

Tomorrow Mandate, snooker has to come first and last.

 

[Wildeman]

Thanks Mandate for your reply but as I have mentioned in earlier posts I have had a seperate electricain test all the wiring and components and I am getting 240v on all connections as and when required. When the valve moves to the final CH only position the pumps fires up and is getting 240v and there is 240v to the boiler.

doitall - I have attached a picture of the airing cupboard piping correctly labelled this time!! I went in the loft last night and cannot see any over vents or valves up there but I noticed the expansion/vent pipe over the F&E tank has been dripping as the top cover of the tank was wet (it was not lined up correctly to the hole for the pipe!!

I tried shutting the system off and putting the diverter valve in the manual flushing mode and then I opened the drain valve at the top of the boiler on the return pipe and there was some air and black "gunk" that shot out followed by "airy" hot water. I closed the valve and then closed all radiator valves (microbote closed feed and return valves) and then switched the heating on on its own and then pipe to the pump and after the pump on the correct side of the diverter valve got instantly hot!! I then opened the radiator valves on the raditor on the landing and that got hot.

I slowlyw went round opening the raditors after bleeding them first but now I have noticed that if the system is in HW and CH the pipework in the airing cupboard gets too hot to touch(radiators are red hot) but when in CH only it cools down but is still warm/hot.

Any further ideas??

View media item 15492

 

[MANDATE]

I'm not convinced that your problem is not related to the wiring.
You have HW and CH together and when HW is satisfied you can't get CH only, cause the radiators cool off.
From cold you can't get CH only.
Your boiler operates correctly when it receives 240v from the Cylinder stat, so there's no reason why it shouldn't work when it receives 240v from the room stat via the mid position valve.
If it receives 240v it does not matter where it comes from, so to me there is something amiss.
I note there is 240v to boiler, but thats not quite the same thing as 240v at the boiler.
I would want to verify the actual voltage at the boiler on the 'switched live' terminal with CH off and on.
Everything you described points to no voltage at boiler which points to wiring problem ( assumming valve is ok).
I would recheck making sure it's the 'switched live' terminal and not the permament live' terminal be checked.
If there's a logical explanation why a boiler will work from 240v from one source but not another, then It will be more than amazing.

Once the boiler is running on CH only, I agree there could be other issues that affect it, such as inadequate circulation causing overheating but you have to get boiler to run on CH only from cold.

 

[Wildeman]

Thanks Mandate,

The voltage at the boiler has been checked to be 240v, I do not have a permenant and switched live at the boiler, there is only one live which comes "live" when feed from the orange wire from the valve to the pump and boiler.

I have a Glow Worm Ultimate 60BF which is a very basic with no PCB's or complicated electronics and fans in it to go wrong

When the valve goes from HW & CH to CH only then water stays warm but not as hot as when it is on HW & CH and the boiler seems to fire intermittently.

Do you still think this is wiring or airlock's/piping issues?

 

[MANDATE]

If the boiler works when HW is involved but not on CH only. What is the difference?
The difference is the source of supply. When HW is involved the cylinder stat provides the 240v.
If it's not involved the valves orange wire provides the 240v and the boiler operates regardless of where the supply comes from.

The wire from cylinder stat and the valves orange each supply power, but not at the same time. These two sources should be joined together in the terminal box, together with the wire/wires going to boiler/pump.
If you had 240v from HW and 0v from CH which is what I was thinking,then you would be looking why the orange is not making proper contact.
I take it it's the same boiler live terminal for CH as it is for HW?.
As the system operates ok on HW/CH until HW is satisfied then surely it must be related to the valve and wiring.
I can't see it being related to air locks or pipe work cause you've had this problem for years.

 

[Wildeman]

I was at first thinking along the same lines as you but when the second electrician looked at the wiring and tested he confirmed that there was 240v to the boiler when HW was running and when CH was running independantly.

There is only one live feed to the boiler that is live no matter whether HW, CH or both are being called for.

The head on the valve was renewed about 6 months ago so would have thought that would be ok. I will check the voltages again to the boiler live in HW and CH only modes.

Did you say you had the same situation, what cured it for you? I have tonight come home and because the HW is satisfied but we still need heat in the raditors the valve has moved but the pipe feeding the pump is almost cold!!

I am getting to the end of my tether with this damn problem!!!

 

[doitall]

Have you got a multimeter.

If so turn the hot water "off" on the programmer, and you should have 240v on the grey wire.

Turn the heating "on", on the programmer and the room stat right up, you should now have 240v on the grey, the white, and the orange.

Let us know.