Which Central heating plan?

[yrob]

Hi,

I've recently had some problems installing a new timer switch (and had help from members of this site) but after some digging have come to the conclusion that I'm not sure which Central Heating plan I have, i.e. Y, C, W etc. I have the following:-

Honeywell ST6400 timer
Honeywell v4043 zone valve
Room Stat
Cylinder stat
Ravenheat CSI Primary boiler - requires pump overrun
Pump is next to the boiler and wired direct
Store hot water in loft - indirect I believe

I would be grateful if anyone could state which plan I have so I can then source the correct wiring diagram for the Control center. Many thanks in advance.

 

[Dan Robinson]

How many Honeywell v4043 zone valves do you have?

 

[yrob]

Just the one Dan.

 

[Dan Robinson]

Are you sure its not a 4073 or 4044?

Is the hot water run through gravity or does the pump pump up to the cylinder too?

 

[yrob]

Dan,

Also worth nothing that my V4043 has no white cable from it, if that helps

 

[yrob]

Cant see the full number (could only read 404....)on the unit but looked at Honeywells site. I have 5 wires, Orange, grey, brown, blue, green/yellow.

The pump (i believe) pumps up to the cylinder too. I have a pipe entry at top and bottom of cylinder and guess the pump pupms to hear and heats tank.

 

[Dan Robinson]

I would guess you have a C-Plan, although you should have the white wire...

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• Dan Robinson
• 8 Feb 2009
• 1

 

[yrob]

Thanks Dan and thats what I came to. Looks like my valve is only mentioned in the s plan. So a bit confused. This all started as I am trying to work out how to get pump over run working.

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• yrob
• 8 Feb 2009
• 1

 

[picasso]

the pump over run is controlled by the boiler so it does not matter what plan you have,you will have to fit an automatic bypass if the valves shut off the water path to the boiler

 

[D_Hailsham]

I would guess you have a C-Plan

But the Ravenheat CSI Primary is designed to be used on a fully pumped system only.

Which type of valve do you have, one on left or one on right?

View media item 5945 View media item 5946

 

[Dan Robinson]

But the Ravenheat CSI Primary is designed to be used on a fully pumped system only.

That is what has been bothering me. I suspect there might be another valve tucked away somewhere. The valve mentioned by the OP is not a mid position valve as they have white wires.

One trick I have used to to get someone to alternate turning the hot water off and listening for the tell-tale noise of the valve springing closed.

Not without its flaws as a technique - but it worked the other day when surveying a boiler swap.

 

[yrob]

The valve I have is the one on the left. There is no other valve wired to the control center and I have hunted around for another but cant find. Is it possible that historically the wrong valve has been installed?

I understand that the boiler controls the over run but without any perm live there how can the pump run - I have checked with a meter?

I have been informed that my overheat switch is called as the pump turns off as the Programmer turns the heating off as the water is too warm for the boiler at that point and is not being pumped around the system after switch off.

As for the pump it does run all the time when the Programmer kicks in so must be fully pumped.

 

[D_Hailsham]

The valve I have is the one on the left. There is no other valve wired to the control center and I have hunted around for another but can't find.

Is this valve in the radiator circuit or the hot water cylinder circuit?

If it is in the radiator circuit, is there a mechanical thermostatic valve in the cylinder circuit e.g a Cyltrol?

Is it possible that historically the wrong valve has been installed?

Answer the questions above first!

I understand that the boiler controls the over run but without any perm live there how can the pump run - I have checked with a meter?

Is the main electrical connection to the boiler, which then supplies the wiring centre; or does it go first to the wiring centre, which supplies the boiler?

I have been informed that my overheat switch is called as the pump turns off as the Programmer turns the heating off as the water is too warm for the boiler at that point and is not being pumped around the system after switch off.

That does not make sense!

As for the pump it does run all the time when the Programmer kicks in so must be fully pumped.

But that's to be expected as your pump is wired directly to the boiler, which only works with fully pumped systems.

 

[Dan Robinson]

Well in that case your system needs a proper looking by someone who has a good understanding of heating electrics.

The pump should be wired to the boiler. The boiler needs a permanent supply and you need to figure out how the cylinder stat functions on your system.

 

[yrob]

Not sure which circuit the valve is on as I've been concentrating on electrics - how do I know?

The main electric connection is to the Pragrammer not boiler, hence no PL there when Prog is off,