Remote control of boiler flow temperature?

[Madrab]

What specifically do you want to know?

What I want to achieve is - with an OT enabled boiler and an OT enable smart control that the system can be set, through the programmer, that there will be 2 separate flow set temps depending on the call.

When the programmer calls for CH, it specifies 50deg flow temp, then when HW is called for it raises that flow temp to 60deg to the cylinder, with the HW set temp taking precedence if both are being called for.

I don't want to have to change the system to be a priority HW system, or have to change the boiler ideally if it's already OT enabled, I also want to keep the system as either an S Plan or Y plan.

 

[Deleted member 267285]

I think it was @Mike_W who referenced Kimbo (aka eco warrior on here) and his knowledge of this stuff, I’m certainly not knocking David, but you may find some useful information here

 

[Madrab]

I think it was @Mike_W who referenced Kimbo (aka eco warrior on here) and his knowledge of this stuff, I’m certainly not knocking David, but you may find some useful information here

Thanks for that and I understand the benefits of PDHW when implementing a new system but that's not what I am looking to achieve. The main argument seems to be that current S/Y plans don't lever the condensing capabilities of modern boilers as they are always running too hot. I want to run the main CH system within the primary condensing temperature window, therefore maximising the boilers efficiency.

A fair number of my clients are looking to retrofit overlay UFH, all to allow lower running temps of the CH, reducing energy use and costs but still have stored HW. Given budgets they are looking to minimise conversion costs, therefore the possibility of needing to add a new fast recovery cylinder and/or run their system @ 80+ deg kind of goes against the whole idea of reducing energy use.

They can understand there may be a possibility of changing their boiler to bring the OT/smart controls into play but balk at the idea of also having to swap out a perfectly good cylinder. Either that or having to add more controls/sensors as that just adds complexity. I also do not want the CH drop out for any amount of time whilst HW is being called for. .

It doesn't seem to be a complicated implementation ask given that OT can already manage flow temps.

 

[Harry Bloomfield]

Thanks for that and I understand the benefits of PDHW when implementing a new system but that's not what I am looking to achieve. The main argument seems to be that current S/Y plans don't lever the condensing capabilities of modern boilers as they are always running too hot. I want to run the main CH system within the primary condensing temperature window, therefore maximising the boilers efficiency.

From basic principles, if it were me, and I wanted to modify an existing system and involving a little electronic design.....

I would add a thermocouple to the flow, then integrate that temperature via a potentiometer, to set a desired maximum flow temperature. The output of that, would then be used to tweak the boilers own flow temperature sensor, so as to fool the boiler controls that it hitting it's maximum set temperature, which would cause it to throttle down it's heat output.

Either that or having to add more controls/sensors as that just adds complexity. I also do not want the CH drop out for any amount of time whilst HW is being called for. .

Again back to basics - a plumbed bypass for the 3 - port, to allow a proportion of the flow, to go to the heating system, when it is serving the HW.

 

[old duffer]

or buy boiler that has this built in
What is it with people believing that there is always an answer and solution to add sensors and controls to a system that was never designed to have them?
ps Need idea on how to convert by old 1995 Vauxhall astra into a 2022 porsche cayenne

 

[vulcancontinental]

Madrab, Ok, the way I've done exactly what you want is to use one of our system boilers and EPH controls all set for OT.

Two heating zones each controlled by an RF stat communicating with their respective receivers by the boiler.

I use the EPH RF hot water stat at the cylinder and receiver by the boiler.

Each receiver operates a zone valve.

Standard cylinder is no problem, this arrangement serves two flats, three people only showers in the flats rather than baths.

All receivers are linked and one receiver chosen as the 'lead' unit. That one is connected OT to the boiler.

Each zone max and min flow temps can be chosen and the one with the highest demand if two are on concurrently will be the boiler flow control.

Each state has a timer so you can program what you want in terms of operation

I was and am very impressed. I linked it to the EPH wi-fi gateway for remote control but that's an option.

 

[Madrab]

Brilliant, thanks for that breakdown VC.

So in short, if zoning wasn't in the equation, using your example then with an OT enabled boiler with an OT programmer then it is the programmer that sets each of the boiler flow temps? So when HW is being called for by the programmer, then a specific flow temp can be set in the programmer and the same for the CH and if both are calling then the higher setting of those takes precedence?

That's how simple I need it to be, if at all possible.

To give you a quick example of one of the clients -

Has an S Plan with an OT enabled boiler and has UFH (with a couple of extra rads) controlled through HeatMiser (HM) room stats and an UH8 RF CC (so each zone is actuator controlled) with a HW cylinder controlled by a HM HW stat all fed to a HM wireless receiver. If possible I want to bridge an OT enabled programmer into that, that then simply controls the boiler and sets the flow temps depending on what it is programmed to call for.

Not sure if this is relative to your OP @JonathanM, didn't mean to hijack

 

[vulcancontinental]

Brilliant, thanks for that breakdown VC.

So in short, if zoning wasn't in the equation, using your example then with an OT enabled boiler with an OT programmer then it is the programmer that sets each of the boiler flow temps? So when HW is being called for by the programmer, then a specific flow temp can be set in the programmer and the same for the CH and if both are calling then the higher setting of those takes precedence?

That's how simple I need it to be, if at all possible.

To give you a quick example of one of the clients -

Has an S Plan with an OT enabled boiler and has UFH (with a couple of extra rads) controlled through HeatMiser (HM) room stats and an UH8 RF CC (so each zone is actuator controlled) with a HW cylinder controlled by a HM HW stat all fed to a HM wireless receiver. If possible I want to bridge an OT enabled programmer into that, that then simply controls the boiler and sets the flow temps depending on what it is programmed to call for.

Not sure if this is relative to your OP @JonathanM, didn't mean to hijack

If I’ve read you right and you want to tie heat miser controls to an OT control; no idea frankly. My system is all one brand, EPH, each receiver, up to 6 zones, is bound to each other and one of them sends the OT command to the boiler.

 

[JonathanM]

If I’ve read you right and you want to tie heat miser controls to an OT control; no idea frankly. My system is all one brand, EPH, each receiver, up to 6 zones, is bound to each other and one of them sends the OT command to the boiler.

Whenever PDHW is discussed, whatever the boiler manufacturer, it always seems to be mentioned in conjunction with using either weather compensation or OT. Can it be installed standalone? What I mean is, can you have PDHW, but where you can still set the heating flow temperature yourself, and just use a basic programmable thermostat? I'm not saying I definitely want to do this, but I am interested in the possibility, and whether it is possible in theory.

 

[muggles]

Whenever PDHW is discussed, whatever the boiler manufacturer, it always seems to be mentioned in conjunction with using either weather compensation or OT. Can it be installed standalone? What I mean is, can you have PDHW, but where you can still set the heating flow temperature yourself, and just use a basic programmable thermostat? I'm not saying I definitely want to do this, but I am interested in the possibility, and whether it is possible in theory.

Yes it's possible, but the whole point of PDHW is to get the water heating out of the way as quickly as possible so you can get back to efficient space heating. OT sets the most appropriate flow temperature for the system at any given time. A fixed temperature with on/off controls is possible, but could reduce comfort levels

 

[JonathanM]

Yes it's possible, but the whole point of PDHW is to get the water heating out of the way as quickly as possible so you can get back to efficient space heating. OT sets the most appropriate flow temperature for the system at any given time. A fixed temperature with on/off controls is possible, but could reduce comfort levels

Thanks. I think I want the opposite of Madrab. I would want to have the heating go off when the DHW comes on.

So, just to make sure I've got it! In theory, I could set a DHW flow temperature of 80C (which I would probably leave set permanently). In this scenario, the heating is currently on, and at this particular time I've got the heating flow set at 45C. I turn the DHW on. The heating switches off automatically. The DHW comes on at a flow of 80C, until the cylinder is satisfied (max 35 mins here). And then the DHW turns off and the heating comes back on with a flow of 45C? (And I don't need WC or OT).

 

[muggles]

Correct. You do need a boiler capable of doing that of course (and an installer who knows what they're doing)

 

[JonathanM]

Only one of four installers so far had heard of it!

 

[muggles]

What's your nearest town? Might be able to recommend someone

 

[JonathanM]

Leeds