Grant VortexBlue Oil Boiler

[Chuck]

Quick question on the setting up of S plan control - I have noticed that when the HW is calling for heat and then the the CH calls for heat then obviously the flow is reduced to the radiators, and not reaching the furthest 🙄
I assume this is usual is to be expected.

It's standard practice to have the DHW zone programmed to come on in the morning for an hour or so (long enough to heat a full tank of water) and then go off when the CH is on during the day. If you are heavy consumers of hot water a half-hour boost for the DHW mid-afternoon will probably do the trick and will happen at a time of day when the starvation of the CH will be less noticeable.

Some people throttle the DHW zone to avoid this problem, but the above approach is preferable in most cases, IMO.

 

[DiggerDave]

It's standard practice to have the DHW zone programmed to come on in the morning for an hour or so (long enough to heat a full tank of water) and then go off when the CH is on during the day. If you are heavy consumers of hot water a half-hour boost for the DHW mid-afternoon will probably do the trick and will happen at a time of day when the starvation of the CH will be less noticeable.

Some people throttle the DHW zone to avoid this problem, but the above approach is preferable in most cases, IMO.

Thanks Chuck - this is just what I expected to hear 👍
The standard times on the Honeywell put both DHW and CH on together 🙄
So have now re-programmed to get the DHW on an hour ahead of the CH
It will all change when I go for continuous over the winter 😅
Thanks once again

 

[Brambles]

Digger,

Whilst programming the DHW to operate outside the window for central heating is fine ( that is normally done to optimise old systems), not when setting up newly installed boilers. Bear in mind that to raise the temperature of 210 litres by 40 degrees will only use around 12kw.

If, at this time of year, when your heating and hot water are on concurrently you are not feeding the last radiator(s) the system is either undersized or not properly designed / piped.

On a well designed system, the impact of generating a tank of hot water from cold whilst concurrently heating the house should be minimal at an ambient outside of zero degrees C. If you are experiencing the problem when the ambient is around 13 degrees, winter may be a challenge for you.

I thought that your plan was to design to a 12 rad system with capacity for further expansion?

I would haul the plumber who designed the system for you back and establish exactly what parameters he /she considered for you.

 

[DiggerDave]

Digger,

Whilst programming the DHW to operate outside the window for central heating is fine ( that is normally done to optimise old systems), not when setting up newly installed boilers. Bear in mind that to raise the temperature of 210 litres by 40 degrees will only use around 12kw.

If, at this time of year, when your heating and hot water are on concurrently you are not feeding the last radiator(s) the system is either undersized or not properly designed / piped.

On a well designed system, the impact of generating a tank of hot water from cold whilst concurrently heating the house should be minimal at an ambient outside of zero degrees C. If you are experiencing the problem when the ambient is around 13 degrees, winter may be a challenge for you.

I thought that your plan was to design to a 12 rad system with capacity for further expansion?

I would haul the plumber who designed the system for you back and establish exactly what parameters he /she considered for you.

Thanks Brambles for your advice
However, hauling the plumber back isn't an option - he lives here and put the original system in 31 years ago 😅
So gonna make the best of what we have got with a few mods as required.
Back in the day, 22mm F & R was installed with 15mm to/from the rads.
All rads now have new or nearly new TRVs with a nice bypass for overrun etc

On a positive note the VortexBlue works very well and is super quiet 😎

 

[SimonG]

Any adjustment on the cylinder feed for throttling back the flow?

 

[DiggerDave]

Any adjustment on the cylinder feed for throttling back the flow?

Thanks for this suggestion Simon 🙂
Any recommendations for doing this please?
At the moment when the DHW valve is open it's full throttle 😛
In the meantime, I'll adjust the start times to avoid both commencing together....

 

[Brambles]

Digger Dave,

If you calculate the required hot water load and the initial ( early morning ) heat load it will give a reasonable indication as to how the flow rates may be divided. Without wishing to consider for you to spend more money - look at Honeywell Evohome. It’s expensive ( £700+), but is very effective at simply zoning ( up to 12 zones) which makes it easier to optimise a heating / dhw system with a boiler that is slightly undersized.

I use it very effectively on a heating system in an old uninsulated house with a 25kw boiler feeding a 210 litre unvented tank and 18 radiators. The Boiler is (in my view) undersized by 5kw - but Evohome has enabled me to tweak an optimise the system to such an extent that it is now an effective system.

Hope this helps

 

[DaveyHep]

So long as your tank and pipes are well insulated, I would leave HW on all the time.

 

[SimonG]

Thanks for this suggestion Simon 🙂
Any recommendations for doing this please?
At the moment when the DHW valve is open it's full throttle 😛
In the meantime, I'll adjust the start times to avoid both commencing together..

Any valve will do the job.