There presumably must be some sort of 'control unit' in addition to what you've shown us?
Kind Regards, John
Smart Immersion Timer
- Thread starter mattyc94
- Start date
Kind Regards, John
Could we have a picture of the cylinder area showing the pipes and any other controls?
No, your hot water cylinder - with the immersion.
- Joined
- 27 Jan 2008
- Messages
- 24,313
- Reaction score
- 2,777
- Location
- Llanfair Caereinion, Nr Welshpool
- Country
I asked my plumber about my oil boiler, in my case a Bosch, and he said there was no run on built into the boiler to cool it after flame had extinguished so to put a motorised valve on the domestic hot water (DHW) would but extra strain on the boiler, the only option is either the old C plan or the Y plan as in both cases the default is DHW open so thermo syphon will allow the circulating water to cool.
The C plan had three stages, as time went on.
Stage 1 was really where the central heating was simply to have a warm bedroom to get up and go to bed in, it was traditionally on a timer and would fire up twice a day, morning and evening, and the open fire would be used during the day, they used a timer like this
so you had an option of once or twice a day, DHW only or DHW plus CH. The method of stopping the central heating working was to simply turn off the pump, but often the water would thermo syphon through upstairs radiators anyway, but they would not get to full heat, minimum time was around 2 hours a day, and we found that was a lot longer than required. I could result in either water not hot enough in summer, with legionnaires being a worry or getting up stairs radiators hot in the summer.
So for summer use only there was an addition, and a thermostat was fixed to the DHW tank, this means in suyou mmer it can be left on 24/7 and the boiler will only fire up when required. However in winter no control of DHW.
The next was to have the tank thermostat work a motorised valve, this means you can set the tank water temperature to under that of central heating circulating water, and you can actually have central heating without DHW, but it means no cooling for the boiler when switched off.
In my house we also have a flat under the house, so two pumps, and motorised valves so flat and house independent for central heating, but the DHW is always on when CH running either flat or house, but can be also run on a timed run without the central heating working, and the DHW is controlled with Nest Gen 3 similar to diagram shown, in summer the boiler is set to run ½ hour a day 5 days a week. That is enough to give us hot water, in real terms it does not run ½ hour as the return water gets too hot and boiler closes down after 20 minutes, I would prefer a thermostat on the water tank, but that is two floors above the boiler and getting three and earth cable between the two is not going to be easy.
Both Nest and Hive will both give DHW on it's own, but in a completely different way, Hive uses a software fix, Nest uses a hard wire fix, with Hive you do not have volt free contacts, so it has to use software, Nest does have volt free contacts, so instead of NO feeding the boiler as normal, the Com feeds the boiler, which is maybe why the installer said it can't be done.
You may need a motorised valve to stop the CH upstairs from thermo syphon, but in most houses simply turning off the pump is enough, only reason for motorised valves in my house, was if flat only ran it would push water around in reverse direction in house, and if house only ran water would be pushed round in reverse direction in the flat.
So I have only timed control for DHW, but so easy to select boost with Nest not really a problem, if going to have a bath I turn on boost other wise ½ hour except for 2 days is enough with the original ½ inch insulation on the tank. Do want to fit a jacket, but lock down stopped me getting one.
The C plan had three stages, as time went on.
Stage 1 was really where the central heating was simply to have a warm bedroom to get up and go to bed in, it was traditionally on a timer and would fire up twice a day, morning and evening, and the open fire would be used during the day, they used a timer like this
so you had an option of once or twice a day, DHW only or DHW plus CH. The method of stopping the central heating working was to simply turn off the pump, but often the water would thermo syphon through upstairs radiators anyway, but they would not get to full heat, minimum time was around 2 hours a day, and we found that was a lot longer than required. I could result in either water not hot enough in summer, with legionnaires being a worry or getting up stairs radiators hot in the summer.So for summer use only there was an addition, and a thermostat was fixed to the DHW tank, this means in suyou mmer it can be left on 24/7 and the boiler will only fire up when required. However in winter no control of DHW.
The next was to have the tank thermostat work a motorised valve, this means you can set the tank water temperature to under that of central heating circulating water, and you can actually have central heating without DHW, but it means no cooling for the boiler when switched off.
In my house we also have a flat under the house, so two pumps, and motorised valves so flat and house independent for central heating, but the DHW is always on when CH running either flat or house, but can be also run on a timed run without the central heating working, and the DHW is controlled with Nest Gen 3 similar to diagram shown, in summer the boiler is set to run ½ hour a day 5 days a week. That is enough to give us hot water, in real terms it does not run ½ hour as the return water gets too hot and boiler closes down after 20 minutes, I would prefer a thermostat on the water tank, but that is two floors above the boiler and getting three and earth cable between the two is not going to be easy.
Both Nest and Hive will both give DHW on it's own, but in a completely different way, Hive uses a software fix, Nest uses a hard wire fix, with Hive you do not have volt free contacts, so it has to use software, Nest does have volt free contacts, so instead of NO feeding the boiler as normal, the Com feeds the boiler, which is maybe why the installer said it can't be done.
You may need a motorised valve to stop the CH upstairs from thermo syphon, but in most houses simply turning off the pump is enough, only reason for motorised valves in my house, was if flat only ran it would push water around in reverse direction in house, and if house only ran water would be pushed round in reverse direction in the flat.
So I have only timed control for DHW, but so easy to select boost with Nest not really a problem, if going to have a bath I turn on boost other wise ½ hour except for 2 days is enough with the original ½ inch insulation on the tank. Do want to fit a jacket, but lock down stopped me getting one.
Well I was wrong, not gravity hot water.
I suppose its possible the system isn't zoned but it is unlikely- yes please to pics of the airing cupboard and whatever the controller was
I suppose its possible the system isn't zoned but it is unlikely- yes please to pics of the airing cupboard and whatever the controller was
Sorry for the late reply. Hopefully what you were after attached.
Attachments
Ok, no sign of any zoning there, the hot water cylinder is just connected as another radiator.
There appears to be a gate valve on one of the coil connections (prob flow but no guarantees) so replacing that with a 2 port motorised valve and some wiring and control gear would allow heating only or heating plus hot water (not that useful i know).
Having hot water only depends on the layout of the pipework. Can you do a topographical map (like the Tube map, doesn't have to be to scale, just needs to show the sequence of devices on the main 22mm circuit from the boiler
There appears to be a gate valve on one of the coil connections (prob flow but no guarantees) so replacing that with a 2 port motorised valve and some wiring and control gear would allow heating only or heating plus hot water (not that useful i know).
Having hot water only depends on the layout of the pipework. Can you do a topographical map (like the Tube map, doesn't have to be to scale, just needs to show the sequence of devices on the main 22mm circuit from the boiler
What a hopeless system...why is it not compliant. Zone valves, timeclocks, thermostats have been best practice for 40 years and a legal requirement for over a decade.
Why is that safety valve outlet on the boiler not plumbed in?
Why is there no backup immersion heater in the cylinder and what is that mini cylinder doing next to the hot water cylinder?
Why is that safety valve outlet on the boiler not plumbed in?
Why is there no backup immersion heater in the cylinder and what is that mini cylinder doing next to the hot water cylinder?
I think it is one of these.
http://www.elemex.ie/external-immersion-heater/
I can see no cable but presume it must be there.
http://www.elemex.ie/external-immersion-heater/
I can see no cable but presume it must be there.
Not even sure where to start with the above. Going by what you say my heating system isn't compliant with heating regulations?
I'm trying to get up to scratch in terms of what I have and then any improvements I can make.
Where are you...Scotland, Northern Ireland, England etc...different regs apply but it's been best practice for decades to have the following...
Have you got a programmer to allow separate hot water and heating times?
Zone valves to allow just the hot water (cylinder) or radiators to be heated?
Room thermostat and thermostatic radiator valves?
What is that bizarre immersion heater doing in the base of the small cylindrical device next to the hot water cylinder?
Is the system sealed (it has a red expansion vessel) or is it a traditional open vented (ie there is a small cistern above the highest radiators)?
Have you got a programmer to allow separate hot water and heating times?
Zone valves to allow just the hot water (cylinder) or radiators to be heated?
Room thermostat and thermostatic radiator valves?
What is that bizarre immersion heater doing in the base of the small cylindrical device next to the hot water cylinder?
Is the system sealed (it has a red expansion vessel) or is it a traditional open vented (ie there is a small cistern above the highest radiators)?
What a pointless device...the heatloss from a modern cylinder is negligable.
The noise must be immense heating up such a small volume, gravity circulation through such small pipework will be hopeless.
I run a dedicated boiler just to heat the cylinder and it runs 24/7. Any minimal heat loss contributes to the space heating for 6 months of the year and it's nice to have a slight background heat in an airing cupboard .
What you should have is an immersion heater in the main cylinder to give a proper backup in case the boiler fails.
Do we assume Northern Ireland?
I've no idea about the regs there (Scotland make up their own) but anyhow a modern economical system should allow full control.
Unless electric is as cheap as oil (unlikely) all the hot water should be heated by the boiler...only use electric when the boiler packs up.
Independent time control of the cylinder heating with a cylinder thermostat on the side of the cylinder to turn the boiler on and off once up to temp.
I guess Nest can control the rads but a TRVS should not be fitted where the Nest resides (otherwise they will fight each other).
Are there really no zone valves? How do you stop the cylinder from heating when the radiators are on?
The noise must be immense heating up such a small volume, gravity circulation through such small pipework will be hopeless.
I run a dedicated boiler just to heat the cylinder and it runs 24/7. Any minimal heat loss contributes to the space heating for 6 months of the year and it's nice to have a slight background heat in an airing cupboard .
What you should have is an immersion heater in the main cylinder to give a proper backup in case the boiler fails.
Do we assume Northern Ireland?
I've no idea about the regs there (Scotland make up their own) but anyhow a modern economical system should allow full control.
Unless electric is as cheap as oil (unlikely) all the hot water should be heated by the boiler...only use electric when the boiler packs up.
Independent time control of the cylinder heating with a cylinder thermostat on the side of the cylinder to turn the boiler on and off once up to temp.
I guess Nest can control the rads but a TRVS should not be fitted where the Nest resides (otherwise they will fight each other).
Are there really no zone valves? How do you stop the cylinder from heating when the radiators are on?