Heat bank & boiler connections

[Norcon]

Jonas posted

1. The control thermostat operating a normally-closed zone valve will allow up to a maximum temperature of 65°C
2. A manually resettable over-temperature cut-out (limit stat) also operating the zone valve will switch off when the temperature rises to 80°C, and
3. The second manually resettable over-temperature cut-out (limit stat), operating the second zone valve will switch off when the temperature rises to 90°C. The second limit stat and zone valve are additional to the previous supply.

Has this been updated to the Building Regulations G3 guides yet?
Do you have a link?

From what I've read at the moment it gives notes on extra safety devices relating to thermal stores which are over 500l/45kw.
No3 would imply a normally open motorized valve would be needed.
What are nu heat using?

If this second valve is spring loaded closed then it has to be held open permanetly using energy and only close in the event of the store reaching 90c which may never happen.
Who makes this ferking crap up?

If its an integrated ch/hw store then how does it work?

It would be easier to fit a large vertical commercial hydraulic decoupler and by-pass this crap. Just get a company to build you one big enough with a big nameplate stating- Hydraulic Decoupler.

 

[JonasX]

Jonas posted

1. The control thermostat operating a normally-closed zone valve will allow up to a maximum temperature of 65°C
2. A manually resettable over-temperature cut-out (limit stat) also operating the zone valve will switch off when the temperature rises to 80°C, and
3. The second manually resettable over-temperature cut-out (limit stat), operating the second zone valve will switch off when the temperature rises to 90°C. The second limit stat and zone valve are additional to the previous supply.

Has this been updated to the Building Regulations G3 guides yet?
Do you have a link?

From what I've read at the moment it gives notes on extra safety devices relating to thermal stores which are over 500l/45kw.
No3 would imply a normally open motorized valve would be needed.
What are nu heat using?

If this second valve is spring loaded closed then it has to be held open permanetly using energy and only close in the event of the store reaching 90c which may never happen.
Who makes this ferking crap up?

If its an integrated ch/hw store then how does it work?

If partial electric failure, the spring closed zone valve will stop heat from the boiler. Yes, it will be energized all the time the boiler is running. The mechanical high temp stat that cools the cylinder using cold mains water would, to me, be a better option.

It would be easier to fit a large vertical commercial hydraulic decoupler and by-pass this crap. Just get a company to build you one big enough with a big nameplate stating- Hydraulic Decoupler.

It would be easier to have a vented thermal store and a coil feeding the CH to avoid sludge build up and avoid pressurized TSs altogether.

Are you right in this only applied to pressurized TS's 500 litres and above? If so then, none of this applies to most domestic TS's and a simple 3 bar blow valve is all that is needed on the cylinder and one on the boiler. I would have a backup on or near the cylinder, as they are cheap enough.

Nu-heat describe what they are using.

Therefore an alternative third mechanism has to be used, and the ‘Approved Document’ suggests a second manually resettable over temperature cut out (limit stat) controlling a second zone valve.
Because the over temperature protection should be staged Nu-heat has designed that the protection will work as follows:

1. The control thermostat operating a normally-closed zone valve will allow up to a maximum temperature of 65°C
2. A manually resettable over-temperature cut-out (limit stat) also operating the zone valve will switch off when the temperature rises to 80°C, and
3. The second manually resettable over-temperature cut-out (limit stat), operating the second zone valve will switch off when the temperature rises to 90°C. The second limit stat and zone valve are additional to the previous supply.

In practice 1 & 2 are combined into a dual-stat, which is internally wired in series.

 

[Dan Robinson]

My mum used to have a wood burner which did the cylinder in the loft. I would love to have seen inside the bottom of the cylinder... the water in the area was phenomenally hard.



I take Mr Legionella has taken a hike from the debate? thank god.


*edit* overlapped posts... I see we are still with this pointless argument over Legionella.

Well Mr Onetap. the OSO valve is factory set and not adjustable. Comments?

 

[Norcon]

I'm hoping to do a small heat bank conversion with a 90/l truck air receiver incorporated into a sealed system.
Like this.....

Mount it vertical on the wall with unistrut and add a few extra tappings and add a plate and flow switch.
I've a gravity dhw system which is ok but running a modern thermo shower with a low head is asking a bit too much.
Have most of the bits lying around apart from the flow switch.
Should be interesting.

 

[SimonH2]

I'm hoping to do a small heat bank conversion with a 90/l truck air receiver incorporated into a sealed system.

Do let us know how you get on.

My thoughts are that :
90l is a bit small for storage, but it will be a good buffer between boiler and CH & DHW.
Steel isn't an ideal material - you only have to look at the vitriol in this and other threads against thermal stores, based on the collection of rust and other 'sludge'.

 

[JonasX]

I have memories of several houses where the owners instinctively drew off hot water when the gurgling and thumping started - usually because there's a solid fuel source in the system. The house I lived in until I was 5 has a coke boiler which (from the stories I've been told) could be entertaining/frightening (depending on your viewpoint) if lit and forgotten about

I recall as a kid a small three high block of flats near us. All three floors had a combined cold tank in the loft the cold feeds went through all flats and the flats teed off. All had open fires and back boilers. One dotty old lady stoked the fire up all day continuously. Her cylinder bubbled over into the shared cold tank. The other flats got hot water down the cold taps and into the toilets.

 

[JonasX]

Steel isn't an ideal material - you only have to look at the vitriol in this and other threads against thermal stores, based on the collection of rust and other 'sludge'.

About sludge creation. Those Albion thermal stores do not have header tanks. The ball cock is in the stored water. There is a lid on the top. You take the lid off and the whole body of water can be seen. This is vented. The whole body of the circulating water in the store is open to full aeration. Not a problem in itself, unless the CH is taken off the cylinder directly, then this is very bad design. This will cause rapid build up of sludge.

a) Have the CH taken off a coil in the cylinder and all is solved.
b) It is also best to have a bronze pump between the boiler and the thermal store as well in these vented header-tankless stores.

I do not know if Albion would provide a CH coil in these thermal stores. If using one of these for DHW only then OK.

Any cylinder coil, in any cylinder is best to be in stainless steel as they do not expand and contract as much as copper. But copper gives better heat transfer for its length. With stainless the coil has to be physically larger to transfer the same amount if heat.

 

[DeltaT2]

Steel isn't an ideal material - you only have to look at the vitriol in this and other threads against thermal stores, based on the collection of rust and other 'sludge'.

About sludge creation. Those Albion thermal stores do not have header tanks. The ball cock is in the stored water. There is a lid on the top. You take the lid off and the whole body of water can be seen. This is vented. The whole body of the circulating water in the store is open to full aeration. Not a problem in itself, unless the CH is taken off the cylinder directly, then this is very bad design. This will cause rapid build up of sludge.

a) Have the CH taken off a coil in the cylinder and all is solved.
b) It is also best to have a bronze pump between the boiler and the thermal store as well in one of these thermals stores.

I do not know if Albion would provide a CH coil in these thermal stores. If using one of these for DHW only then OK.

Any cylinder coil, in any cylinder is best to be in stainless steel as they do not expand and contract as much as copper. But copper gives better heat transfer for its length. With stainless the coil has to be physically larger to transfer the same amount if heat.

Too much of an expensive faff around, just fit a un-vented cylinder. Cheap as chips & will last for years.

 

[JonasX]

Too much of an expensive faff around, just fit a un-vented cylinder. Cheap as chips & will last for years.

Unvented cylinders are not cheap and need an expensive annual service. They do not do CH or UFH, only DHW. They do not maximize the efficiency of the boiler. So they are not applicable. It is clear you cannot understand something so simple. You are comparing apples with oranges.

Although there are some DHW only heat banks around that do not blow up that are comparable and superior to unvented cylinders. Simon's Youtube vids are an eye opener.

A heat bank with a CH take-off coil inside is just a cylinder with a coil inside. Just like millions of others. There are no expensive, complex, pressure controls, which are replaced by a simple plate heat exchanger, flow switch and pump. How simple. The CH side has a cheap sealed system kit attached with a modulating Smart type of pump and TRVs all around. You can even have full CH & DHW electric backup.

Get to know how they work. You will not look back.

 

[DeltaT2]

Far better performance from an un-vented cylinder, system boiler & 'Y' plan, much cheaper install price & the boiler will be in the condensing mode much longer. Heatbanks & Thermalstores need to sit at 80C all the times to produce hot water, they fill with sludge in no time & fail.

NEVER BUY A SLUDGE BUCKET!!!

 

[JonasX]

Far better performance from an un-vented cylinder, system boiler & 'Y' plan, much cheaper install price & the boiler will be in the condensing mode much longer. Heatbanks & Thermalstores need to sit at 80C all the times to produce hot water, they fill with sludge in no time & fail.

Cowboy, pay attention at the back there. Repeating twaddle does not make it right. You are like a stuck record.

a) Dan's sits at 65C.
b) They do not fill with sludge
c) They do not fail being simpler
d) An unvented cylinder and Y plan is is about the most inefficient system you can have which needs an annual service for the cylinder.

NEVER BUY A SLUDGE BUCKET!!!

I agree. Buy a properly designed thermal store or heat bank and have it professionally installed. Avoid Cowboys who call them sludge buckets.

 

[Norcon]

SimonH2 wrote

based on the collection of rust and other 'sludge'.

I'm hoping it gathers sludge. Yes indeed. Like a sediment trap.
I'll fit a large bore ball valve at the bottom and crank it open every now and then to jettison any debris.
Like that big rocket on page 10 losing its booster tanks.

 

[Onetap]

I'm hoping it gathers sludge. Yes indeed. Like a sediment trap.
I'll fit a large bore ball valve at the bottom and crank it open every now and then to jettison any debris.
Like that big rocket on page 10 losing its booster tanks.

I put a big settlement tank on a MTHW system once. The system was full of sludge, due to neglect, and parts of it were drained regularly for amendments, which would put some of the sludge into suspension. One boiler (fire tube) had failed due to sediment and hot-spots. The tank was about 8' tall, ISTR. When it was first drained, after some years, I was told that there was nothing in the bottom of it.

You can get condensation lying in the bottom of compressed air receivers and they can be corroded internally if they've been neglected. I drained 30 litres out of one that had a capacity of about 50 litres.

 

[Norcon]

I was told that there was nothing in the bottom of it.

You should have fitted an albion mainsflow.

 

[Onetap]

You should have fitted an albion mainsflow.

I know, but they didn't do them in the 5 MW size I needed.