Anyone knows where I can get a Randal 3033 Timer Controller.

[Benny5]

Might be a good idea. You don't mention a hot water thermostat (see pic). It will be on the side of the HW cylinder. Do you have one?

As you can gather from the system description and the various niggle I am experiencing, this setup is currently on life support.
I am just nursing it along for the moment as I plan to replace the whole thing in about two years. The layout of my kitchen units will have to be altered as the current Baxi is much more compact than the combo replacements. Also, adding a shower in the current airing cupboard area. So a lot of planning and money needed.
For this reason I omitted the H/W thermostat from the proposed upgrade, planning on using the old one for now. I was hoping the new programmer and the C/H thermostat could be utilised on any new system.

Once again many thanks for all your help.

Regards,

Benny.

 

[D_Hailsham]

As for the device currently fitted; under normal operation how should this device operate? I would expect it to remain closed unless pressure builds up at which point it would open. Therefore, the pipe work should remain cooler on the return section. Also, which way should the directional arrow point; at the moment it is counter to the actual flow.

The current device is just a tap. When the slot is across the valve the tap is closed; when it is along the valve it is open. Obviously you can set it to a position somewhere between, but there will always be a flow through it, even when it is not required. The important thing is that it must never be completely closed as there could be nowhere for the water to go when the pump is in overrun. Until you can get it changed to an ABV, try setting it to halfway open.

I noticed the arrow pointing the "wrong" way and couldn't work out why the fitter did that. I don't think it's worth bothering about as changing it to an ABV is more important.

OK , so you do have a cylinder thermostat. They haven't changed for years, so what you have will still be OK when you change your boiler in a few years time.

I still think you would be better off getting a more up-to-date digital thermostat or programmable stat. They are completely different from the old mechanical stats so the temperature measuring device is much more accurate.

 

[Benny5]

The important thing is that it must never be completely closed as there could be nowhere for the water to go when the pump is in overrun. Until you can get it changed to an ABV, try setting it to halfway open.

It’s currently set at 45 Degrees.
Enquiring from a local merchant I can get one of these. http://www.honeywelluk.com/Products/Valves/Bypass-Valves/DU145/ for about £15.
As I have to modify the pipework anyway, the fact that it is an angle rather than straight shouldn’t matter. Hope to get time to fit it in next week. Not sure how I am going to ‘tune’ it once fitted.

OK , so you do have a cylinder thermostat. They haven't changed for years, so what you have will still be OK when you change your boiler in a few years time.

I don’t expect my future system will have a H/W cylinder.

I still think you would be better off getting a more up-to-date digital thermostat or programmable stat. They are completely different from the old mechanical stats so the temperature measuring device is much more accurate.

Once I have sorted the current hardware problem then I will look at replacing the Programmer and C/W Stat. Incidentally do you know if this type of change requires Part P certification or is classified as replacing ‘like with like’.

Regards,

Benny.

 

[D_Hailsham]

Not sure how I am going to ‘tune’ it once fitted.

The DU145 will do fine it is 22mm fitting. The Honeywell instructions assume that you have the pump curve available, which you won't have and, as it's a very old pump, it's no longer available. However there is an easy way to adjust it.

Before running the boiler, set the valve to the maximum setting.

Ensure that the radiator thermostats are set to their normal control temperature.

Turn on the boiler, and allow the temperature to stabilise, at this stage the valve will be closed.

Turn the valve knob slowly counter-clockwise until the valve begins to open. (This can be monitored by feeling the temperature of the
outlet connection of the valve.)

Turn the knob clockwise half a turn to complete the setting process. The setting should normally be between 2 and 3.

You may have to adjust the setting slightly of you find there is noise in the system or the pipe on the return side is continually hot.

I think it would be called a like-for-like change. But who's to know you did it?

 

[Benny5]

Not sure how I am going to ‘tune’ it once fitted.

The DU145 will do fine it is 22mm fitting. The Honeywell instructions assume that you have the pump curve available, which you won't have and, as it's a very old pump, it's no longer available. However there is an easy way to adjust it.

Before running the boiler, set the valve to the maximum setting.

Ensure that the radiator thermostats are set to their normal control temperature.

Turn on the boiler, and allow the temperature to stabilise, at this stage the valve will be closed.

Turn the valve knob slowly counter-clockwise until the valve begins to open. (This can be monitored by feeling the temperature of the
outlet connection of the valve.)

Turn the knob clockwise half a turn to complete the setting process. The setting should normally be between 2 and 3.

You may have to adjust the setting slightly of you find there is noise in the system or the pipe on the return side is continually hot.

I think it would be called a like-for-like change. But who's to know you did it?

That fantastic, thank you so much. I hope to get it sorted this week.

Will probably need help with the wiring changes for the programmer/stat change-out.

Regards,

Benny.

 

[Benny5]

Just sorted the ABV and now that aspect of the system is working fine. Thanks for all the assistance.

I am now looking at replacing the old room stat with something where the wiring is similar to the existing Honeywell T603A so that installation would be relatively straightforward.
With no online information on the T603a I have managed to locate a very old diagram (see attached).
View media item 35806
The existing connections are;
T1 - Yellow/Green [No sign of any sleeving at either end]
T3 – Brown.
T4 – Blue.
With Power ON and Switch OFF; Blue-brown = 240V.
With Power ON and Switch ON; Brown-G/Y = 240V.

Would something like the Honeywell T6360B or the DT90E be a simple swap, if so, which colour goes to which terminal?
Also attached is a summary of the existing system wiring layout together with some wiring diagrams for the above two units.
View media item 35805
(Edit; 18-07-11. 21:40) Images restated for clarification.

Regards,

Benny.

 

[D_Hailsham]

The existing connections are;
T1 - Yellow/Green [No sign of any sleeving at either end]
T3 – Brown.
T4 – Blue.
With Power ON and Switch OFF; Blue-brown = 240V.
With Power ON and Switch ON; Brown-G/Y = 240V.

The voltages do not make sense.

Can you check them with the stat set to min and then with it set to max.

Check G/Y to Blue and Brown to Blue.

 

[Benny5]

The existing connections are;
T1 - Yellow/Green [No sign of any sleeving at either end]
T3 – Brown.
T4 – Blue.
With Power ON and Switch OFF; Blue-brown = 240V.
With Power ON and Switch ON; Brown-G/Y = 240V.

The voltages do not make sense.

Can you check them with the stat set to min and then with it set to max.

Check G/Y to Blue and Brown to Blue.

Just to clarify; the initial readings were taken across the terminals at the 'stat end' with the actual 'stat head' removed and not at the termination box.

The readings you requested are;
G/Y to Blue - Min. = 0 Volts.
BR to BL - Min. = 240 Volts.

G/Y to Blue - Max. = 0 Volts.
BR to BL - Max. = 0 Volts.

Once again thanks for your assistance.

 

[D_Hailsham]

Just to clarify; the initial readings were taken across the terminals at the 'stat end' with the actual 'stat head' removed and not at the termination box.

So which Switch were you talking about in the first tests?

The readings you requested are;
G/Y to Blue - Min. = 0 Volts.
BR to BL - Min. = 240 Volts.

G/Y to Blue - Max. = 0 Volts.
BR to BL - Max. = 0 Volts.

Even stranger!

I was expecting:

G/Y -Blue (Min and Max) 240V
Br - Blue (Min) 0V
Br - Blue (max) 240V

 

[Benny5]

Just to clarify; the initial readings were taken across the terminals at the 'stat end' with the actual 'stat head' removed and not at the termination box.

So which Switch were you talking about in the first tests?

This is the Programmer switch.

The readings you requested are;
G/Y to Blue - Min. = 0 Volts.
BR to BL - Min. = 240 Volts.

G/Y to Blue - Max. = 0 Volts.
BR to BL - Max. = 0 Volts.

Even stranger!

I was expecting:

G/Y -Blue (Min and Max) 240V
Br - Blue (Min) 0V
Br - Blue (max) 240V

Is it possible the wiring of T603a was not modified in line the Field Replacement document (Attached above) when the old Valve V6057A was replaced with the V4043H at the same time as the boiler change out all those years ago? I found this document with the Boiler Manual.
Could this explain the current wiring arrangement?

Again, thanks for your help.

Regards,

Benny.

 

[D_Hailsham]

This is the Programmer switch.

OK

Can you identify what the other ends of the cable connected to the thermostat are connected to? I assume it goes into a junction box, so it's either the devices connected to the same pair of terminals, or the name of the terminals (e.g Room stat Live), which are important.

 

[Benny5]

This is the Programmer switch.

OK

Can you identify what the other ends of the cable connected to the thermostat are connected to? I assume it goes into a junction box, so it's either the devices connected to the same pair of terminals, or the name of the terminals (e.g Room stat Live), which are important.

This is my system wiring connections;

View media item 35805
Is this sufficient to for you to make a judgement.

Regards,

Benny.

 

[D_Hailsham]

This is my system wiring connections;

View media item 35805
Is this sufficient to for you to make a judgement.

Yes, that's good enough. I didn't examine it properly the first time you posted it.

The wiring does not follow either of the diagrams you posted for the T603A.

Can you confirm that, for example, the Brown in "Programmer 1" connects to 1 at the programmer and 1 at the terminal block? And the same for the other Programmer terminal numbers?

I will then be able to give you the wiring for a DT90E.

 

[Benny5]

The wiring does not follow either of the diagrams you posted for the T603A.

It appears to be some form of hybrid!!!

Can you confirm that, for example, the Brown in "Programmer 1" connects to 1 at the programmer and 1 at the terminal block? And the same for the other Programmer terminal numbers?

I will then be able to give you the wiring for a DT90E.

Terminal 1 of the programmer is linked to terminal 1 of the terminal block. T2 Prog to T2 Block and so on to T8. Terminal block positions 9, 10 & 11 are hot linked to the programmer.

Thanks you once more.

Regards,

Benny.

 

[D_Hailsham]

[Terminal 1 of the programmer is linked to terminal 1 of the terminal block. T2 Prog to T2 Block and so on to T8. Terminal block positions 9, 10 & 11 are hot linked to the programmer.

That's what I thought; but you can't be too careful, particularly when advising remotely.

Right, here goes (some of this is tidying up, i.e using correct colours where possible):

Turn the power off

At Programmer
Disconnect Brown, Blue and G/Y fromT1, T2 and T3

Connect Blue to T1 and Brown to T2. (Green/Yellow is not required so it should be made safe - insulating tape or terminal block.)

At Terminal Block
Disconnect Brown from T1, G/Y from T2 and Blue from T3 (cable from programmer)
Connect Blue to T1 and Brown to T2. Green/Yellow is not required so it should be made safe - insulating tape or terminal block)

At T603a Thermostat
Disconnect all wires
Make the G/Y safe
Install the new DT90E Thermostat
Connect Brown to A
Connect Blue to B with some red sleeve or insulating tape round it to show it is switched live

At terminal block
Disconnect the cable from the thermostat (T2=G/Y, T3=Blue, T10=Brown)
Reconnect Brown to T2
Reconnect Blue to T10 with red sleeve/insulating tape
Make the G/Y safe

Turn Power ON

Job Done