Heat Only Boiler + S Plan+ + Weather Compensation Query

[magician2905]

Hi looking for some advice here if anyone would be so kind.

Our existing system consists of an Ideal Logic Heat H15 heat only boiler paired to a 180L Kingspan Tribune XE Unvented Indirect Hot Water Cylinder (this is the Dual Stat version).

Zone 1 (Downstairs) consists of 7 Radiators + Plumbed Plinth heater, Zone 2 (Upstairs) is 6 Radiators. All radiators have manual TRV heads apart from 1 in each zone.

The boiler supplies both HW and CH and is controlled by a Drayton Wiser Kit 3 Controller that has individual time schedules for Hot Water production and Zone heating temperature & times.

On the Logic Heat H15 the "SET" temperature dial (E = 67'C) determines the temperature for both the CH and HW and has to be set to a minimum of 64'C so that the hot water is actually still hot enough when it comes out the taps.

This doesn't seem to be particularly efficient as we are driving the radiators too high just so that we can maintain out hot water temp.

We are considering adding Weather Compensation to the boiler.

Doing this we can then set the appropriate curve for the heating and this would then use, one of, the Cylinder Thermostats to control the temperature of the hot water production which seems a more efficient way to use the boiler?

So the query is would we be able to retain our 2 Zone heating setup? The upstairs zone is rarely on so losing that function would be less than ideal.
Would we still be able to continue to use the Drayton Wiser Controller and Zone Thermostats or would we need some other controller setup?

The Opentherm stuff is a red herring it only works with certain Combination Boilers unfortunately.

Look forward to your assistance.

 

[gmartine]

Dual stat or dual immersion, is the cylinder stat is set correctly?

 

[ShaunCorbs]

Sorry to say no, not on a heat only you would need to change the boiler to a system eg vouge system boiler and hope you have a spare core etc

 

[magician2905]

Dual stat or dual immersion, is the cylinder stat is set correctly?

Dual Stat, Single Immersion.

One controls the electric Immersion itself.

I am led to believe that the second stat can be used to call for heat from the boiler (so would take over in the event we installed weather compensation) or in a different boiler configuration.

Our last house had an open vented system, heat only boiler, with the old style cylinder and a cut out in the insulation for the cylinder thermostat which then controlled the DHW.

 

[magician2905]

Sorry to say no, not on a heat only you would need to change the boiler to a system eg vouge system boiler and hope you have a spare core etc

Shaun thanks for reply.

Haven't got a scooby (clue) what you are referring to when you talk about a spare core

I am trying to get my head around the reasoning so can I ask why you think that changing to a System Boiler would be necessary.

A System Boiler is predominately a Regular (or Heat only) boiler with an internal pump rather than an external pump. I appreciate different boilers types/models/brands have more built in features than the crappy Logic Heat H15 which is essentially a giant gas fired kettle.

On the flip side this also means that "the "brains" of the H15 are essentially external (in our case a Wiser Kit 3) and the zone valves themselves don't care where the signal to open or close comes from as long as there is a call for heat from somewhere.

• The Cylinder Stat controls the call for heat for the HW, either constantly or on a schedule (using some kind of timer which can either be completely dumb ie mechanical pins or something more advanced)
  • That's Zone Valve 1 (normally open?)
• The Weather Compensation Kit automatically controls the call for heat/temperature of the CH based on it's setpoint?
  • That's Zone Valve 2 (normally closed?)
• A secondary Thermostat placed upstairs (currently its in the master bed) is set to say 10'C - which is off in our case (in fact 14'C is about the baseline temp through winter).
• If we decide we want to heat upstairs we turn this Thermostat up, to say 18'c, which then opens Zone Valve 3 (normally closed?). Wouldn't this work as long as the weather compensation is calling for heat already?

I hope that makes sense?

 

[ShaunCorbs]

Because when it’s warmer the cylinder would only get to 30 ish degrees so you would have to use the immersion also there’s no wc kit available for a heat only boiler for this reason

The vogue boiler has two switch lives one for the cylinder and another just for heating so you can have different temperatures etc

 

[magician2905]

Because when it’s warmer the cylinder would only get to 30 ish degrees so you would have to use the immersion also there’s no wc kit available for a heat only boiler for this reason

The vogue boiler has two switch lives one for the cylinder and another just for heating so you can have different temperatures etc

Oh, now I understand.

There is a Weather Comp kit for the Ideal Logic Heat H15 - details below:

The HW then becomes controlled by the Cylinder Thermostat. As previously noted the Kinspan Tribune XE Indirect Unvented Cylinder has 2 Thermostats - one for the electrical Immersion heater and the second is unused in our current config but would be used when adding the weather comp kit to the install.

Just add www to these.

idealheating.com/products/weather-compensation-kit

idealheating.com/uploads/documents/Weather_Compensation_Kit_User_Guide.pdf

This kit is suitable only for the domestic gas boilers listed below:
Note
1. A timer should be fitted to the system so that CH will be switched off when appropriate
2. The Connector (Frame 1, item C). is prefitted to certain boilers. Boilers that don't have this fitted are marked with an * on page 2.

• HEAT BOILERS
• Logic Heat
• Logic Heat H
• Logic+ Heat
• Logic Max Heat

• COMBI BOILERS
• *Logic Combi
• *Logic Combi C
• IE Logic Combi ES
• Logic Code Combi ES
• Logic+ Combi
• *Independent Com
• *Independent+ Com
• *i-mini C Vogue
• Combi C GEN2 Vogue
• Combi C IE GE
• Logic Max Combi C
• Vogue Max Com
• SYSTEM BOILERS
• Logic System
• Logic System S
• Logic+ System
• Vogue System S GEN2
• Vogue System S IE GEN2
• Logic Max System S Vogue Max System

 

[ShaunCorbs]

If you look at the diagram it requires two switch lives eg picture 1

To my knowledge they only have one well the old ones did unless they’ve updated for the newer model might be worth a check on yours first

 

[magician2905]

If you look at the diagram it requires two switch lives eg picture 1

To my knowledge they only have one well the old ones did unless they’ve updated for the newer model might be worth a check on yours first

That's the same Wiring Diagram shown in the current Weather Comp instructions but on page 7 goes on to say

 

[ShaunCorbs]

Yes so normal heating sl 1

Cylinder demand sl 2

Wc is used if sl1 is calling

But goes to full rate if sl2 is calling you need to know if you have 1 or 2 sl terminals