Worcester boiler and Drayton LPIII programmer.

[StevieTee]

How you doing guys,

Been asked to connect up a Worcester Greenstar 37CDi boiler and a Drayton LPIII time switch (there is NO thermostat wanted). Hands up, I've not done a boilers so needing some advice.

I was was thinking along the lines of;

1) Spur supplying boiler with 3 Amp fuse.
2) Spur supplying Drayton with 3 Amp fuse.
3) 4 Core between boiler and Drayton.

But out can't find proper connections between the two though. Any willing to gives a diagram or some sort of help?

Cheers.

 

[Geordie Spark]

Page 28 of the Instruction manual -Installation Commissioning and Servicing.

I am familiar with this boiler as I have fitted several - including on in my own home.

I am NOT familiar with the Drayton LPIII time switch.

I am at a loss to understand why the customer does not want a thermostat, but ours is not to reason why.

I am not sure why you propose using 4 core flex. Have another think about it.

Ok that's that out of the way so let us begin.

Is the spur already in place? If not here's an elegant way to do this if the time switch will fit onto a back box / pattress box.

Get one of these: http://www.ebay.co.uk/itm/35mm-DOUBLE-DUAL-PLASTIC-SURFACE-MOUNT-BACK-BOX-TWIN-2-GANG-WALL-PATTRESS-UK-/310378611131

and fit your FCU in one side and your timer in the other. (use recessed metal version of this box if you wish.)

Get a lump of FIVE core flex and use 3 of these for your L N E from the load side of the FCU to the boiler L N E terminals. This is the power supply for the boiler, and at this point with the FCU in the on position the boiler should fire up. The flex should exit the FCU through the normal flex outlet of the FCU

Use some offcuts of the 5 core to connect the L N E on the timer to the load side of the FCU - this powers the timer to make it go tick tock.

Use 2 cores of your 5 core and connect one to terminal LR and the other to LS at position S10 in the boiler (see page 29 of the manual) There should be a link factory fitted here - remove it and stick your wires in instead.

Now go back to the timer. there should be 2 terminals there which you'll connect the other ends of your wires connect to LR and LS in the boiler. Remember, I am not familiar with this actual timer, but it can't be much different to any other.

So now when the FCU is switched on you will have power going to the boiler and it will fire whenever a hot tap is turned on.

You will also have power going to the timer so now it should be going tick tock and when the timer calls for heat the boiler will fire and the radiators should get hot.

I would have posted pictures & diagrams for you but I'm crap at things like that, but hopefully you'll understand what I have written here.

If you don't have the manual you can download it as a PDF (I think) from the Worcester website.

Be careful how you route the cable in the boiler / pipe area - the hottest one is the 22mm on the left as viewed from the front.

 

[philbet]

so your saying double up on the load side of the spur

 

[alanl]

Yes. Do not have 2 supplies supplying one piece of equipment.
Think about it. You turn off the FCU at the boiler, so you think it is safe (clearly ignoring safe practice, but a plumber may not be aware).
Then while you are holding the line cable, knowing it is turned off, the programmer starts up and makes the cable live, and you hit the wall, and have a shaking arm all day.

 

[UNG]

Try this link gives you loads of boiler wiring diagrams http://www.worcester-bosch.co.uk/cache/file/482/gas-boiler-wiring-guide.pdf

 

[StevieTee]

Cheers guys.

Geordie Spark, they dont want a thermostat because they want to control every room individually using those radiator control valves.

Thanks for the help.

 

[Geordie Spark]

so your saying double up on the load side of the spur

Do you have a problem with that??

Do you REALLY want it to be fed from to separate supplies??

 

[Geordie Spark]

Cheers guys.

Geordie Spark, they dont want a thermostat because they want to control every room individually using those radiator control valves.

Thanks for the help.

You're very welcome for the help, and I did guess that using all TRVs is what customer wants, but I "think" there's a regulation somewhere that says you need a Room Stat somewhere in the system, but don't quote me on that until you've looked a bit further into it.

 

[chris murphy]

How you doing guys,

Been asked to connect up a Worcester Greenstar 37CDi boiler and a Drayton LPIII time switch (there is NO thermostat wanted). Hands up, I've not done a boilers so needing some advice.

I was was thinking along the lines of;

1) Spur supplying boiler with 3 Amp fuse.
2) Spur supplying Drayton with 3 Amp fuse.
3) 4 Core between boiler and Drayton.

But out can't find proper connections between the two though. Any willing to gives a diagram or some sort of help?

Cheers.

"Hello Steve Tee",

Geordie Spark is absolutely correct when He refers to a Regulation that requires a Room Thermostat to be fitted to EVERY Central Heating System - with the possible exception of a Heating System which has the latest RF Radiator Thermostatic Valves and Heating Control Unit which provides `Boiler Interlock` when either there is a Demand for Heat from some of the RF TRV`s - OR when there is NO Demand for Heat from the TRV`s.


That Regulation is contained in Part L1 of the Building Regulations where Heating Controls are specified and in `Normal` circumstances a Room Thermostat - preferably a Programmable Room Thermostat is a VITAL Temperature Control.

Even if your Customer wants to ignore the fact that Part L1 of the Building Regulations stipulates that there is a Room Thermostat installed they would be ill advised to omit it because even when the Building is warm enough and the Radiator TRV`s close down the Boiler Thermostat will keep regularly firing the Boiler to keep the Boiler Heat Exchanger water at the Boiler Thermostat setting.

This is called `Boiler Thermostat Cycling` - and this unnecessary Firing of the Boiler obviously costs Money.


As an comparison - regarding My own Home`s Central Heating [installed by Me] - in this kind of Weather / Temperatures when my Programmable Room Thermostat reaches temperature and turns Off the Boiler it can take up to about 45 Minutes for the temperature to drop so that the Room Stat turns the Boiler back on.


If there was NO Room Thermostat the Boiler Thermostat would probably turn on the Boiler / Burners 5 times during that period to keep the Heat Exchanger water at the Boiler Stat temperature - a waste of Gas / Money !


When the Boiler is not firing Heat is being lost from Boiler Heat Exchanger / Water content via the Flue-way which is open to outside Air temperature - this `Cycling` of the Boiler Burners would be more frequent / costly in colder temperatures / weather.



HERE IS A BRIEF QUOTE ABOUT THE REQUIREMENT FOR A ROOM THERMOSTAT FROM A GUIDE TO PART L1 OF THE BUILDING REGULATIONS:

QUOTE:

Heating controls:

• If either a boiler or an entire heating system is replaced
adequate controls must be installed (or the existing controls
must be upgraded).The minimum requirement is for fully
pumped systems incorporating time controls, zone
temperature controls and boiler interlock.

Good Practice Guide 302 suggests an appropriate minimum set of controls.

• If a whole heating system is replaced there must be a full
programmer to provide independent time control of the
heating and hot water. Mini programmers and standard
programmers do not comply.

• All new and replacement systems must include a room
thermostat and ‘boiler interlock’ (ie the thermostat switches
the boiler off when there is no demand for heating).

• If a whole heating system is replaced, the controls must permit
independent temperature control in two separate zones: the
living and sleeping areas.This can be achieved with a single
room thermostat and thermostatic radiator valves.


END OF QUOTE


I hope that this is helpful - although obviously it is not down to You to advise your Customer about the Energy Efficiency Regulations / Building Regulations applicable to Gas Appliances / Heating systems and the minimum Controls specified by those Regulations I thought that You MIGHT want to know about this so that You can advise them if You wish.



EDIT: IF your Customer decides to fit a Room Thermostat for the reasons above - the Radiator in the area where the Thermostat is installed MUST be correctly sized / calculated for the Heat requirement and must NOT have a Thermostatic Radiator valve fitted - in fact it should have Lockshield valves fitted to each end to prevent the Radiator from being turned Off.

An incorrectly calculated / sized Radiator OR turning the Radiator Off [or the operation of a TRV] would have an adverse effect on the whole Heating System regarding the operation of the Room Thermostat.

On some Heating Sysyems the Room Thermostat is in a small Hallway where the Room doors are left open and the Hallway is effectively Heated by Heat Gain from the Rooms - if a Radiator is also installed this can lead to the Room Thermostat being `Satisfied` prematurely in relation to the Heating of the rest of the Home / Building.


Regards,

Chris

 

[Geordie Spark]

Hi Chris.

Nice to see we're singing from the same hymn sheet .............. I use a programmable Room Stat too.

 

[chris murphy]

Hi Chris.

Nice to see we're singing from the same hymn sheet .............. I use a programmable Room Stat too.

"Hello Geordie Spark",


As You know apart from obviously having a well designed Heating system - Professionally installed with the Pipework well insulated for prevention of Freezing and Heat Loss - at the very least under the Ground Floor [obviously any pipework in Roof space must be insulated] and of course Loft Insulation [Optimum Thickness = 270mm laid as: 100mm Base layer - Plus 170mm Cross Laid `Top layer`] / Cavity Wall Insulation where appropriate - a Programmable Room Thermostat is a very useful and Cost effective Central Heating `Timed Temperature` Control.


A good quality Programmable Room Thermostat is the best Temperature Control that anyone could fit for very little Cost - as You know it is beneficial in terms of both an `Energy Efficiency improvement` over a Basic Room Stat - And it has additional `Comfort / Lifestyle benefits` for the Home / Building / Occupiers over a Basic Room Thermostat because of being able to Set different Temperatures at different Times of the Days.



* FOR OTHER MEMBERS / READERS:

N.B: My comments above about insulating Heating system pipework are NOT meant to convey that only pipework under a Ground / Suspended Floor or pipework in a Roof space is ALL that requires Insulating.

The Primary Flow and Return to a Cylinder Coil should be insulated against Heat Loss to AT LEAST where the pipework enters the `Building Fabric` / Floor / Wall - I personally insulate these pipes along their entire length - also the Hot Water outlet and Cylinder Cold Feed pipes should be Insulated where `exposed` - I would insulate the Hot Water pipework along its entire length to as close to the Taps as is feasible.

Although insulating pipework correctly is quite time consuming and therefore `Costly` I also insulate at least the Main Flow and Return pipework throughout the Building - but usually I will insulate ALL of the Heating system pipework where possible with a 9mm Wall thickness Pipe Insulation - this does not cause any problems with Notching out joists or relaying Floorboards.

I personally do NOT subscribe to what I feel is an Industry `Get out clause` regarding Insulating Heating system pipework that Heat from uninsulated pipework under upper Floors is `Warming the Fabric of the Building`.


I hope that my message to Steve above about the need for a Room Thermostat will be of some help / interest to Him / His Customer / and perhaps some Members / future Readers on here.


Regards,

Chris

 

[wozz]

Being a worester it will want the supply taking to the boiler first and then the controls wired from outputs on the boiler.

 

[Geordie Spark]

Being a worester it will want the supply taking to the boiler first and then the controls wired from outputs on the boiler.

............ and it will have - via the five core flex.