Ideal Vogue System Max - what does it mean when it says it's "fully modulating"?

[harrypotter]

I have an Ideal Vogue Max System 32 boiler with HW cylinder in Y-plan. It's paired with a Boss Therm programmer and basic Danfoss RX thermostat/receiver. I'm looking to get a new thermostat with internet connectivity like Nest for example. I've also been looking at OpenTherm or Weather Compensation and if I'm correct it's difficult to do this without setting it all up for DHWP. I don't really want to do this as we have a lot of HW demand (which would mean CH would be off a lot).

Anyway I believe that would mean getting a simple on/off thermostat and not using the OT or WC connections on the boiler. But this brings me to my question. I don't believe my current thermostat is modulating, but it seems like the boiler itself modulates (based on difference between flow and return maybe?). The service manual says CH output is fully modulating between 6.4 and 32kW. It also later shows how to change pump modulation in these settings. Are these two the same, or can it modulate both the 'flame size' and pump? Secondly, does this modulation occur even with a simple on/off thermostat or does it require OT or WC connected?

Thanks.

 

[Exedon]

We have now installed a number of vogue system boilers with DHWP (X plan) with weather compensation including my own .
Even after filling a large bath my own is 1800 x 850 hot water recovery is around 6 minutes.
So unless your hot water requirement is huge its not a problem remember all the millions of combi owners don't have heating and hot water at same time.
To be blunt who installed a modern 32kw boiler on Y plan? We get get rid of them as part of new install.

 

[Madrab]

Ideal do my nut in sometimes. On the Vogue Combi Gen2, they haven't implemented OT but it the Vogue Max System they have. I have a client just now that could so benefit from their C40 Gen2 having OT, but alas .....

@harrypotter ... A modern boiler will modulate once it comes up to temp and the output flow temps meet a coded threshold. As far as implementing weather control via OT then that's all that does, it allows an outdoor sensor to manage the system temps according to specific setpoints and the weather/air temps. I don't believe that PDHW must be implemented, though it is a benefit of OT and when a system is setup to run like that.
A modulating pump is especially useful in a system that has zone valves/TRV's/Bypasses etc as it allows the pump to alter it output automatically to suit a changing system as certain section/rads etc open and close and pressures/flows vary. Both do different things but add up to better overall efficiencies.

A thermostat doesn't modulate as such, rather it just controls the temp in the space that it lives, when the CH is being called, by turning the boiler on and off. A lot will anticipate (hysteresis) the heat requirement and turn the boiler on and off before it's hit it's setpoint, as it knows the system takes time to react and change the actual temp.

You state that there is a high demand for HW in your house then PDWH is ideal for your requirements, as that's exactly what it is designed to do. It minimises the time that the CH is off and the house cools down but allows the HW store to replenish itself as fast as possible. Of course, This will need a high recovery cylinder and the system set up correctly.

As suggested a Y plan is a very dated and now considered to be an undesirable and a superseded system configuration and whoever installed your system should have suggested and recommended it be changed.

 

[harrypotter]

We have now installed a number of vogue system boilers with DHWP (X plan) with weather compensation including my own .
Even after filling a large bath my own is 1800 x 850 hot water recovery is around 6 minutes.
So unless your hot water requirement is huge its not a problem remember all the millions of combi owners don't have heating and hot water at same time.
To be blunt who installed a modern 32kw boiler on Y plan? We get get rid of them as part of new install.

Thanks. That's very helpful - I don't know much about boilers.

Can you explain DHWP programming and what you mean when you say hot water recovery is 6 minutes? I'm probably wrong but I thought that with DHWP/X plan, if CH is programmed to be on say 5pm-10pm, then HW cannot also be 'on' (or 'active' awaiting to fill a cooled cyclinder from the draw of a bath) so I could only program for HW to be on outside of CH programmed times?

As for who installed it on a Y-plan. It was done when the house was built in 2011, boiler was replaced with the Ideal 32kW in 2020 by british gas. I think they suggested 32kW. Often we have 8 people so that why I said HW demand is high, but again perhaps this is still fine with DHWP?

 

[Exedon]

As Madrab has indicated DHWP is excellent for your requirement
Ideally needs a cylinder with a high recovery coil.
I leave my hot water on constant it only runs when there has been a demand and even then only 5 or 6 minutes as I said above.
Even in 2011 S plan would have been considered normal especially on a larger system.

 

[Notch7]

Can you explain DHWP programming and what you mean when you say hot water recovery is 6 minutes? I'm probably wrong but I thought that with DHWP/X plan, if CH is programmed to be on say 5pm-10pm, then HW cannot also be 'on' (or 'active' awaiting to fill a cooled cyclinder from the draw of a bath) so I could only program for HW to be on outside of CH programmed times?

If you have hot water priority, the system has 2 zone valves, one normally open and one normally closed.

If you have a situation where the heating is on so water is being pumped around the radiators……when the hot water cylinder stat calls for heat, the valve directing to the radiators will close and the valve to the cylinder will open.

The benefit of hot water priority is that a boiler like the Ideal Vogue has 2 inputs one for hot water and one for heating, so you can set the hot water at 80 degrees and the heating at say 50

I had an Ideal Vogue system boiler fitted with new rapid recovery cylinder, hot water priority layout and weather compensation…..it’s fantastic, when outside temp is say 10 dems, the boiler will heat the rads to around 38 degrees, the house is warm enough it’s a lovely background heat. When say running a bath, the hot water priority takes over and the boiler sends 80 deg water to the cylinder coil…..it doesn’t take much time to heat the water and the house doesn’t drop noticeably in temperature during that time.


I can thoroughly recommend it, Ideal have designed a very simple Weather Comp system which works great with hot water priority and we just use it with a basic stat and controller.

The only thing is the boiler doesn’t modulate down enough and the boiler has to short cycle quite a bit to keep the flow temps down to below 40.

 

[harrypotter]

As Madrab has indicated DHWP is excellent for your requirement
Ideally needs a cylinder with a high recovery coil.
I leave my hot water on constant it only runs when there has been a demand and even then only 5 or 6 minutes as I said above.
Even in 2011 S plan would have been considered normal especially on a larger system.

About leaving HW on all the time, does that not waste energy keeping the water in the cylinder at the temp the cylinder stat calls for (60-65C)? So for example when HW isn't really being used during the day then doesn't it waste energy keeping the water hot? or is it basically using the same amount of energy as letting the water cool down over the course of the day to then heat it all back up in the evening?

 

[Exedon]

Modern hot water cylinders must lose less than 2 kw per 24 hrs. Many do better 1 kw or less but remember it's not lost heat as such it goes towards heating your house most months of year . Or keeping your airing cupboard warm

 

[harrypotter]

You state that there is a high demand for HW in your house then PDWH is ideal for your requirements, as that's exactly what it is designed to do. It minimises the time that the CH is off and the house cools down but allows the HW store to replenish itself as fast as possible. Of course, This will need a high recovery cylinder and the system set up correctly.

Very helpful, thank you. Is it absolutely necessary to have a high recovery heat cylinder, and what rough heat from cold/recharge time would deem it to be rapid enough? My current 250l cylinder says it has "fast reheat" but the actual spec doesn't seem that fast - 27mins to reheat "from 15°C to 65°C after drawing off 70% of the capacity".

 

[Notch7]

Very helpful, thank you. Is it absolutely necessary to have a high recovery heat cylinder, and what rough heat from cold/recharge time would deem it to be rapid enough? My current 250l cylinder says it has "fast reheat" but the actual spec doesn't seem that fast - 27mins to reheat "from 15°C to 65°C after drawing off 70% of the capacity".

In my experience most high recovery cylinders are unvented…if you want unvented that gives you lots of options

There are only a few available that are vented.

High recovery cylinders have a larger surface area of heating coils, either longer and or finned, they also have more insulation.

It isn’t absolutely necessary, but it is a benefit - I had one fitted when I had a new system fitted

 

[harrypotter]

Remember it's not lost heat as such it goes towards heating your house most months of year . Or keeping your airing cupboard warm

Good point, never thought of it that way. Except mine is in my garage unfortunately!

 

[harrypotter]

In my experience most high recovery cylinders are unvented…if you want unvented that gives you lots of options

There are only a few available that are vented.

High recovery cylinders have a larger surface area of heating coils, either longer and or finned, they also have more insulation.

It isn’t absolutely necessary, but it is a benefit - I had one fitted when I had a new system fitted

It is unvented indirect yes. I'm thinking I really do need a fast recharge actually. 4 bathrooms, I AirBnB it sometimes so can go from 2 people to 10 people. The existing 250 or 300L cylinder seems vastly undersized so changing to DHWP now might mean CH is off too much. Need to rethink.

 

[harrypotter]

@Notch7 Forgot to ask too, what control system (Nest, Honeywell etc?) do you use with you Ideal boiler and with weather comp I don't understand if you still use a room thermostat with that or not?