Do I really need heating controls?

Fembot

We have to replace a very old back boiler for our gas central heating. We have received 3 quotes with or without Heating Controls. As the Grant only applies to the new heating controls I wonder whether to bother with that as it will involve more disruption when it comes to installation. The house will probably be sold within the next 5 to 10 years so not really looking for a long-term solution. Any advice on this would be appreciated?

Heating controls are a basic requirement as they give you heating and hot water at the correct temperature which saves you money while giving you a comfortable living environment also these controls would often be looked for by most home buyers

Dardania

Heating controls would have a pay back within a small number of years in terms of energy saved.
Plus, it is a major part of the BER certificate whether you have controls or not. When people buy houses, they take the BER rating as a subtle indicator of how "turn-key"the rest of the house is.

Wearb

I think that was of the best benefits of going for the grant, is that it requires a certain standard of plumbing to meet grant requirements.

John.G

gary71 wrote: »

Heating controls are a basic requirement as they give you heating and hot water at the correct temperature which saves you money while giving you a comfortable living environment also these controls would often be looked for by most home buyers

Are there any control systems that differentiate between the hot water cylinder temperature required and the water temperature required for space heating?. The (few) three zoned gas fired systems that I have seen have manual temperature settings selectable between 40c and 80C, I have seen the selected setting down around 50/55C with a cylinder thermostat temperature set at 60/65C so the cylinder temperature will never reach 60C under these conditions. I presume the boiler would have to incorporate some logic to achieve this as well.

Sleeper12

Fembot wrote:

We have to replace a very old back boiler for our gas central heating. We have received 3 quotes with or without Heating Controls. As the Grant only applies to the new heating controls I wonder whether to bother with that as it will involve more disruption when it comes to installation. The house will probably be sold within the next 5 to 10 years so not really looking for a long-term solution. Any advice on this would be appreciated?

The heating controls are the part that will save you money. That's why you can get a grant for them.

Why not stick with the very old back boiler?

Why not replace the old boiler if really needed without the grant?

Sleeper12

John.G wrote:

Are there any control systems that differentiate between the hot water cylinder temperature required and the water temperature required for space heating?. The (few) three zoned gas fired systems that I have seen have manual temperature settings selectable between 40c and 80C, I have seen the selected setting down around 50/55C with a cylinder thermostat temperature set at 60/65C so the cylinder temperature will never reach 60C under these conditions. I presume the boiler would have to incorporate some logic to achieve this as well.

Maybe I'm reading this wrong.
Upstairs zone one, downstairs two, hot water zone three. The cylinder has an individual stat, downstairs has a stat and upstairs has a stat

John.G

Sleeper12 wrote: »

Maybe I'm reading this wrong.
Upstairs zone one, downstairs two, hot water zone three. The cylinder has an individual stat, downstairs has a stat and upstairs has a stat

Thats correct. The selectable temperature that I am referring to is on the boiler front and controls the temperature of the primary water in the circuit, this in turn heats the water in the hot water cylinder via its coil so if it set lower than the cylinder stat then the cylinder hot water will never reach its set point?

Edit: I am referring to the Boiler Stat.

With the controls and boiler Logic you have now you can send 60-80c to your cylinder for quick reheat times looking to achieve a cylinder temperature of 60c and then much lower flow temperatures to your rad circuit ie.. 50-56c, keeping the boiler condensing throughout the heating cycle achieving maximum efficiency for your money.

When you factor in the heating is only on when you want it on and at the precise room temperature you require then I would say correctly wired and fitted controls are a must in every home.

John.G

gary71 wrote: »

With the controls and boiler Logic you have now you can send 60-80c to your cylinder for quick reheat times looking to achieve a cylinder temperature of 60c and then much lower flow temperatures to your rad circuit ie.. 50-56c, keeping the boiler condensing throughout the heating cycle achieving maximum efficiency for your money.

When you factor in the heating is only on when you want it on and at the precise room temperature you require then I would say correctly wired and fitted controls are a must in every home.

Thanks Gary, is this logic only incorporated in some boilers only?, a relation has a Vokera Vision 20S and it has a form of automatic temperature control for space heating, its called SARA, when selected it will automatically raise the boiler set point temperature if it sees if one of the room thermostat contacts is closed for more than 20 minutes.
Do you know if the above boiler or similar can be configured to raise the boiler temperature and increase the circ pump speed to give you quick reheat times or does the boiler have to come configured to do this automatically when it sees a hot water demand only?.

John.G

John.G wrote: »

Thanks Gary, is this logic only incorporated in some boilers only?, a relation has a Vokera Vision 20S and it has a form of automatic temperature control for space heating, its called SARA, when selected it will automatically raise the boiler set point temperature if it sees if one of the room thermostat contacts is closed for more than 20 .
Do you know if the above boiler or similar can be configured to raise the boiler temperature and increase the circ pump speed to give you quick reheat times or does the boiler have to come configured to do this automatically when it sees a hot water demand only?.

It will usually need a separate hot water demand for the boiler to ignore the outdoor sensor(fitted to achieve lower heating flow temperatures) and switch between the different heating and hot water flow temperatures/characteristics.

I don’t know the above boiler but there are many ways to the top of the mountain and manufacturers have their own individual logic or way of interacting with controls which in some cases are so advanced the boiler will email the service engineer indicating a fault before the home owner is aware and in some cases the engineers phone call with a appointment is the first time the home owner is aware of any problem, but ignoring the fancy stuff even the most basic S-plan controls design which has been around since the 60s will serve you well.

LenseOnLife

Hi,

I realise that this is an old thread - but VERY useful information for this Newbie. I've moved into a house with a grant oil boiler and controller of unknown vintage, nice to get some basic info before I wrestle with it and try to work out if it is working ...

Cheers

LenseOnLife

Hi All,

OK - just realised that I was looking at the wrong date all along - no wonder I was getting confused. I had mistaken the 'join date' with the posting date - I know, what a basic mistake! Learning as I go along

Cheers

Dtp1979

John.G wrote: »

Thanks Gary, is this logic only incorporated in some boilers only?, a relation has a Vokera Vision 20S and it has a form of automatic temperature control for space heating, its called SARA, when selected it will automatically raise the boiler set point temperature if it sees if one of the room thermostat contacts is closed for more than 20 minutes.
Do you know if the above boiler or similar can be configured to raise the boiler temperature and increase the circ pump speed to give you quick reheat times or does the boiler have to come configured to do this automatically when it sees a hot water demand only?.

Any boiler that offers weather compensation add ons should have a separate hot water temp simply because on hot days the cyl temp could potentially be heated to only 35 degrees and this is not acceptable.

John.G

Dtp1979 wrote: »

Any boiler that offers weather compensation add ons should have a separate hot water temp simply because on hot days the cyl temp could potentially be heated to only 35 degrees and this is not acceptable.

Has anyone got a link to any boiler manufacturer that automatically raises the boiler temperature to say 65C or whatever when water heating only is on via its zoning valve?. I have searched a few times but can,t seem to find any info on it. Oil fired condensing boilers have a much higher minimum boiler stat setting of 65C (Grant Vortex), the Firebird Enviromax minimum is 60C. Gas fired boilers seem to have a minimum setting of 40C so one could say that all of these boilers should be able to be configured to to raise the temperature automatically on hot water demand only?.

Dtp1979

John.G wrote: »

Has anyone got a link to any boiler manufacturer that automatically raises the boiler temperature to say 65C or whatever when water heating only is on via its zoning valve?. I have searched a few times but can,t seem to find any info on it. Oil fired condensing boilers have a much higher minimum boiler stat setting of 65C (Grant Vortex), the Firebird Enviromax minimum is 60C. Gas fired boilers seem to have a minimum setting of 40C so one could say that all of these boilers should be able to be configured to to raise the temperature automatically on hot water demand only?.

Any modern Ariston boiler can. That’s how I have it in my own house and do for several customers

John.G

John.G wrote: »

Has anyone got a link to any boiler manufacturer that automatically raises the boiler temperature to say 65C or whatever when water heating only is on via its zoning valve?. I have searched a few times but can,t seem to find any info on it. Oil fired condensing boilers have a much higher minimum boiler stat setting of 65C (Grant Vortex), the Firebird Enviromax minimum is 60C. Gas fired boilers seem to have a minimum setting of 40C so one could say that all of these boilers should be able to be configured to to raise the temperature automatically on hot water demand only?.

Oil boilers are different animals and don’t have the controllability of gas also your gas boiler can be set to 80c+ But with better controls, cleaner heating systems and better education homeowners are finding 50ish is a better choice for heating but the higher temperatures for hot water are down to the logic and then the sparks readying the MI.

DGOBS

The reason oil boiler have a higher minimum setting, it if the return temperature to the boiler is less than 55ºc you will begin to get condensing occurring in the mild steel section of the boilers primary heat exchanger, which will lead to rotting of the boiler.

John.G

DGOBS wrote: »

The reason oil boiler have a higher minimum setting, it if the return temperature to the boiler is less than 55ºc you will begin to get condensing occurring in the mild steel section of the boilers primary heat exchanger, which will lead to rotting of the boiler.

I understand that, one "advantage" of this is that even if the boiler stat is set to its minimum setting of 60/65C the hot water (cylinder) will still be relatively "hot"
compared to a gas boiler with its boiler stat set (manually) as low as 40C.
Its just that I just dont seem to be able to find any info on the automatic raising of the boiler temperature (either on gas or oil) when hot water only is required.
Dtp1979's Ariston is doing this but I don't see any info anywhere re this.
I am interested from a technical point of view, I have a Firebird 90s Heatpac, setpoint 70C which, allowing for boiler stat hysteresis gives a hot water cylinder temperature of 58/61C.
Apart from any Legionella considerations, raising the boiler set point temp will give a much faster hot water recovery time, the setpoint can then return to a much lower value for CH and return the boiler to its condensing/partially condensing mode.

Dtp1979

John.G wrote: »

I understand that, one "advantage" of this is that even if the boiler stat is set to its minimum setting of 60/65C the hot water (cylinder) will still be relatively "hot"
compared to a gas boiler with its boiler stat set (manually) as low as 40C.
Its just that I just dont seem to be able to find any info on the automatic raising of the boiler temperature (either on gas or oil) when hot water only is required.
Dtp1979's Ariston is doing this but I don't see any info anywhere re this.
I am interested from a technical point of view, I have a Firebird 90s Heatpac, setpoint 70C which, allowing for boiler stat hysteresis gives a hot water cylinder temperature of 58/61C.
Apart from any Legionella considerations, raising the boiler set point temp will give a much faster hot water recovery time, the setpoint can then return to a much lower value for CH and return the boiler to its condensing/partially condensing mode.

This might be achievable with a weather compensation unit for an oil boiler

John.G

John.G wrote: »

I understand that, one "advantage" of this is that even if the boiler stat is set to its minimum setting of 60/65C the hot water (cylinder) will still be relatively "hot"
compared to a gas boiler with its boiler stat set (manually) as low as 40C.
Its just that I just dont seem to be able to find any info on the automatic raising of the boiler temperature (either on gas or oil) when hot water only is required.
Dtp1979's Ariston is doing this but I don't see any info anywhere re this.
I am interested from a technical point of view, I have a Firebird 90s Heatpac, setpoint 70C which, allowing for boiler stat hysteresis gives a hot water cylinder temperature of 58/61C.
Apart from any Legionella considerations, raising the boiler set point temp will give a much faster hot water recovery time, the setpoint can then return to a much lower value for CH and return the boiler to its condensing/partially condensing mode.

it’s in the MI and is one of the wiring diagrams offered.

Hot water priority for gas boilers has been around since the 80s in the domestic gas heating design, there is a lot of catch up being played because if it wasn’t for grants most home owners and lazy RGis would still choose not to fit basic heating controls also you have to factor in mostly Sparks wire heating systems and they have no or very little training in heating controls or on the impact the controls they are fitting will have, that’s why something as simple as a room stat is looked upon as being useless in most Irish homes.

John.G

gary71 wrote: »

it’s in the MI and is one of the wiring diagrams offered.

Hot water priority for gas boilers has been around since the 80s in the domestic gas heating design, there is a lot of catch up being played because if it wasn’t for grants most home owners and lazy RGis would still choose not to fit basic heating controls also you have to factor in mostly Sparks wire heating systems and they have no or very little training in heating controls or on the impact the controls they are fitting will have, that’s why something as simple as a room stat is looked upon as being useless in most Irish homes.

Thanks Gary, if allowed, would you mind please posting a Link to one of these drawings.

Dardania

I wired one of these for a relative a few years ago - see page 23 of this: http://acwilgar.co.uk/Boiler-Manual-PDF/Baxi/System%2035-60%20&%2060-100.pdf

This is a pre condensing boiler, so I think the purpose of the DHW versus CH switching was to limit the flow temperature (to prevent scalds from DHW) rather than encourage the boiler to condense in CH mode, but either way you can see it does differentiate between the functions.

And as gary71 guessed, a sparks tried wiring it before they called me to help out after getting smoke from a room thermostat... Sparks are not trained in heating controls wiring sadly, which is a shame as it is truly great to get heating controls working.

I also recall a few years ago on a school project, we spec'd an oil boiler in the region of 80kW - this was a condenser, so I was able to differentiate the flow mode depending if there was just space heating needed (with weather compensation), or top up of the DHW calorifier. Just an additional terminal on the PCB to do it.

https://www.manualslib.com/manual/1349937/Ariston-Clas-Net-One.html?page=31#manual

S-plan with out door sensor.

Hot water priority predates HE boilers, the idea was to send 80c usually to a unvented cylinder with a 26kw+ coil allowing to reheat large volumes of hot water to 60c very very quickly then switching to the lower temperatures 55-65c required for the heating circuit.

John.G

gary71 wrote: »

https://www.manualslib.com/manual/1349937/Ariston-Clas-Net-One.html?page=31#manual

S-plan with out door sensor.

Hot water priority predates HE boilers, the idea was to send 80c usually to a unvented cylinder with a 26kw+ coil allowing to reheat large volumes of hot water to 60c very very quickly then switching to the lower temperatures 55-65c required for the heating circuit.

Yes, I've read a bit over the years about those quick recovery coils, they also need very high flow rates through the coil, the 26 KW above will need over 37 LPM to keep the coil delta T to 10C, I presume the logic will tell the circ pump to increase speed as well or maybe it looks at the boiler heat exchanger flow and return thermistors and "demand" a delta T of 10c or whatever (as well as increasing the boiler temp to 80C).

John.G

Dardania wrote: »

I wired one of these for a relative a few years ago - see page 23 of this: http://acwilgar.co.uk/Boiler-Manual-PDF/Baxi/System%2035-60%20&%2060-100.pdf

This is a pre condensing boiler, so I think the purpose of the DHW versus CH switching was to limit the flow temperature (to prevent scalds from DHW) rather than encourage the boiler to condense in CH mode, but either way you can see it does differentiate between the functions.

And as gary71 guessed, a sparks tried wiring it before they called me to help out after getting smoke from a room thermostat... Sparks are not trained in heating controls wiring sadly, which is a shame as it is truly great to get heating controls working.

I also recall a few years ago on a school project, we spec'd an oil boiler in the region of 80kW - this was a condenser, so I was able to differentiate the flow mode depending if there was just space heating needed (with weather compensation), or top up of the DHW calorifier. Just an additional terminal on the PCB to do it.

That's very interesting, I spoke to a Vokera chap re the Vision 20S and he said that the max cylinder temperature is limited to whatever the boiler stat is manually set to, except that it is set higher than the cylinder stat. It does tell you to set the boiler stat higher than the minimum (see page 4 of attachment) so again the space heating requirement and the hot water requirement is really just a compromise on this boiler from a economy point of view??

Edit: file is too big: Just google Vokera Vision 20S users manual or something like that.