Mega Flo vs Thermal store

[JonasX]

How can a system which requires the water temperature to be a constant 78°C (implying a return temp of 58°C to 68°C) be considered "efficient"? The boiler will be permanently running above the temperature at which condensation starts.

I keep thinking of this. If I run a big bath and the store temperature is around 20 to 25C, when reheating by the boiler the return temperature will be very low and enhancing efficiency. So your claims can't be true?

 

[D_Hailsham]

If I run a big bath and the store temperature is around 20 to 25C, when reheating by the boiler the return temperature will be very low and enhancing efficiency.

You are assuming that the boiler does not come on when the flow temperature drops.

Most boilers work with a max differential of about 25C so, if the flow is 78C, the return would not drop below 53C. Also, the boilers thermostat will bring the boiler on when the temperature drop about 10C.

I agree there will be some stratification. But 40C is way more than any boiler is designed to handle.

 

[shambolic]

Fit a Fermox type of filter on the CH return to the thermal store then sludge will not build up.

Megalflows are not compatible with thermal stores as Megaflows do not do CH and run at high pressures. This is ignorance on the part of not very bright plumbers. Thermal stores enhance the boiler operation.

Was the Albion thermal store OK in using two taps, then it went wrong?

Most new thermal stores are stainless steel, which is far better. This Albion appears to be copper.

Plumbers who do not know what a thermal store is are not educated, time served college educated plumbers. Avoid them. Even I can understand them.

Thermal stores are not old hat.

Plumbers who cal thermal stores sludge buckets should give up the game.

Thermal store can be de-sludged/descaled.

Inhibitor, about 3 cans of X100, should be used every 4 years.

What is the fuss?

Tell that to the 150 houses in Larbet and cambuslang in Glasgow that have constant bother with them. So bad in fact they are acting almost like a large battery and using the aluminium hex in the boiler like a sacrificial anode.
The 28 mm pipes on the primaries(the direct type of Albion) are down to about 10 mm and when you take one out after a year there and section it to see inside is 10" of brown sludge in the bottom and about an inch of sludge adhered to hw coil.
Apparently corrosion is sped up by a factor every 10 degrees(this came from a chemist and a sentinel engineer tasked with trying to stop the problems on these two site)
The installers went back flushed all systems with 800 put in brand new Albion mains flow direct cylinders and new hex in boiler. and 8 bottles of 100
A year later the same thing is starting again.
So forgive me if I don't really like thermal stores.

 

[shambolic]

I know exactly how any heatbank or thermalstore works son. Would you like to call me a cowboy to my face?

They gather any sludge from a system, therefore they are sludge buckets.
By there very nature they can't transfer enough heat to the non ferous part of a radiator system. So all the sludge gathers in that primary water. Pyshics can't change that. You two are not Water Systems aka Dr Drivel etc etc by any chance?

Beginning to look like a reincarnation of they two/same wallopers.
Almost an identical thread and argument from that numpties every few months before he's told to take a hike.
Can admin not check his ISP and ban itif it's the same imposter over and over again?

 

[SimonH2]

I know exactly how any heatbank or thermalstore works son. Would you like to call me a cowboy to my face?

Make some of the statements you've made here to my face and I would, so YES.

They gather any sludge from a system, therefore they are sludge buckets.

Radiators collect sludge from any system, so is a radiator also a sludge bucket ? Also, as I mentioned earlier, when you look at the diameter of a typical store, you could collect a lot of sludge and it really doesn't matter - it's not affecting anything (unlike the piles of sludge in the diagrams used to sell flushing services).

By there very nature they can't transfer enough heat to the non ferous part of a radiator system. So all the sludge gathers in that primary water. Pyshics can't change that.

What on earth does that mean ?

You two are not Water Systems aka Dr Drivel etc etc by any chance?

No, I'm not.

Most boilers work with a max differential of about 25C so, if the flow is 78C, the return would not drop below 53C. Also, the boilers thermostat will bring the boiler on when the temperature drop about 10C.

I agree there will be some stratification. But 40C is way more than any boiler is designed to handle.

For a thermal store (rather than heat bank) there is a lot of stratification.
Firstly, if you run the rads fully TRVd with smart pump*, then the return flows can be quite cool - not much above room temp under light load conditions. This will make the bottom of the store quite cool - certainly well below 53˚
Secondly, when you draw off hot water, you are putting mains temperature cold water into the bottom of the DHW coil -so it will cool the bottom of the store even more.
* IMO, any other arrangement would not be sensible.

In my setup, I had to artificially raise the boiler (turn the pump up high, use a TMV in the return) return to avoid condensing as it's still an old non-condensing boiler.
I am quite happy that I could setup a newer boiler to operate almost all the time in condensing mode - mind you I don't run the store all that hot (the stat is set at 65˚, the top will be somewhat warmer). You need to bear in mind that we have a known and fixed hydraulic environment and so you can set the flow at minimum required to make the boiler operate correctly without having to allow a margin for the variation in a normal system. Of course, part of selecting the boiler might mean avoiding manufacturers that can't make a boiler capable of working with low flow rates and large differentials - not all of them impose an arbitrary maximum of 25˚C (or whatever).

For heat banks (also included in what most people group as thermal stores) you don't need such high temperatures anyway - because they can have such large capacity PHEs. There are a different set of issues with heat banks though.

FWIW, I agree with those (including yourself) who criticise the high temperatures quoted by most thermal store manufacturers. The main reason for this is that it is an easy way to raise the nominal power output for the DHW coil. If you can manage with slightly less DHW output then they can be run considerably cooler.

 

[DeltaT2]

I know exactly how any heatbank or thermalstore works son. Would you like to call me a cowboy to my face?

They gather any sludge from a system, therefore they are sludge buckets.
By there very nature they can't transfer enough heat to the non ferous part of a radiator system. So all the sludge gathers in that primary water. Pyshics can't change that. You two are not Water Systems aka Dr Drivel etc etc by any chance?

Beginning to look like a reincarnation of they two/same wallopers.
Almost an identical thread and argument from that numpties every few months before he's told to take a hike.
Can admin not check his ISP and ban itif it's the same imposter over and over again?

Deffo is Water Systems aka Dr Drivel, Big Burner...etc etc.
No experienced Tradesman would fit a sludge bucket if they could fit an unvented cylinder....Q Water Systems rocket video!!
As a cheap nautral point in a system with several system heat sources they have there place. But that's about it!!

 

[shambolic]

I know exactly how any heatbank or thermalstore works son. Would you like to call me a cowboy to my face?

Make some of the statements you've made here to my face and I would, so YES.

They gather any sludge from a system, therefore they are sludge buckets.

Radiators collect sludge from any system, so is a radiator also a sludge bucket ? Also, as I mentioned earlier, when you look at the diameter of a typical store, you could collect a lot of sludge and it really doesn't matter - it's not affecting anything (unlike the piles of sludge in the diagrams used to sell flushing services).

By there very nature they can't transfer enough heat to the non ferous part of a radiator system. So all the sludge gathers in that primary water. Pyshics can't change that.

What on earth does that mean ?

You two are not Water Systems aka Dr Drivel etc etc by any chance?

No, I'm not.

Most boilers work with a max differential of about 25C so, if the flow is 78C, the return would not drop below 53C. Also, the boilers thermostat will bring the boiler on when the temperature drop about 10C.

I agree there will be some stratification. But 40C is way more than any boiler is designed to handle.

For a thermal store (rather than heat bank) there is a lot of stratification.
Firstly, if you run the rads fully TRVd with smart pump*, then the return flows can be quite cool - not much above room temp under light load conditions. This will make the bottom of the store quite cool - certainly well below 53˚
Secondly, when you draw off hot water, you are putting mains temperature cold water into the bottom of the DHW coil -so it will cool the bottom of the store even more.
* IMO, any other arrangement would not be sensible.

In my setup, I had to artificially raise the boiler (turn the pump up high, use a TMV in the return) return to avoid condensing as it's still an old non-condensing boiler.
I am quite happy that I could setup a newer boiler to operate almost all the time in condensing mode - mind you I don't run the store all that hot (the stat is set at 65˚, the top will be somewhat warmer). You need to bear in mind that we have a known and fixed hydraulic environment and so you can set the flow at minimum required to make the boiler operate correctly without having to allow a margin for the variation in a normal system. Of course, part of selecting the boiler might mean avoiding manufacturers that can't make a boiler capable of working with low flow rates and large differentials - not all of them impose an arbitrary maximum of 25˚C (or whatever).

For heat banks (also included in what most people group as thermal stores) you don't need such high temperatures anyway - because they can have such large capacity PHEs. There are a different set of issues with heat banks though.

FWIW, I agree with those (including yourself) who criticise the high temperatures quoted by most thermal store manufacturers. The main reason for this is that it is an easy way to raise the nominal power output for the DHW coil. If you can manage with slightly less DHW output then they can be run considerably cooler.

Absolute pish

 

[SimonH2]

Absolute pish

Ah, a well reasoned and "grown up" response.

 

[JonasX]

If I run a big bath and the store temperature is around 20 to 25C, when reheating by the boiler the return temperature will be very low and enhancing efficiency.

You are assuming that the boiler does not come on when the flow temperature drops.

I am assuming the heat from the cylinder is extracted very quickly. Far quicker than what a boiler can replenish. After running a large bath the bottom of the thermal store can be very cool indeed. Very cold return temperature enhance boiler efficiencies. This counters your claims.

Many thermal stores have two anti boiler cycling thermostats. This means the boiler will not be cutting in until about 1/3 to 1/2 of the heat is extracted with a very cool bottom.

I agree there will be some stratification. But 40C is way more than any boiler is designed to handle.

I believe if the return temperature is say 25C and the boiler works at a differential of 25C, then the boiler's controls operate at 50C flow, depending on boiler of course.

 

[Norcon]

Absolute pish

Ah, a well reasoned and "grown up" response.

I would treat shambolics posts with a pinch of salt.
He had some images of plastic pipe up recently claiming they were eaten by mice when in fact they were probably sabotaged with a grinder.
Ne never did reply to the said post to verify otherwise. Either way it was very suspicious.

 

[JonasX]

Tell that to the 150 houses in Larbet and cambuslang in Glasgow that have constant bother with them. So bad in fact they are acting almost like a large battery and using the aluminium hex in the boiler like a sacrificial anode.
The 28 mm pipes on the primaries(the direct type of Albion) are down to about 10 mm and when you take one out after a year there and section it to see inside is 10" of brown sludge in the bottom and about an inch of sludge adhered to hw coil.

That is one of my points. The makers of the better stores say this only occurs because of bad thermal store design and bad installation design. I made that clear yet you push this crap housing estate as consensual of all thermal stores.

If the rad loops are isolated from the store using a coil sludge just does not occur. Because of the reputation of thermal stores and sludge, I went heavily into them as most UFH firms use thermal stores.

 

[JonasX]

Beginning to look like a reincarnation of they two/same wallopers.

What is this one babbling about.

Indus complained that many cowboys went to his house and could not understand something so simple, a basic thermal store. You, and others here, fall into this walk in and walk out category. I find this very disappointing. Are you guys the sort who just picked it up and not being trained? A trained plumber would know thermal storage and all of its advantages.

 

[JonasX]

Absolute pish

Ah, a well reasoned and "grown up" response.

It is clear this shambolic does not understand a part of his trade. I find this amazing.

 

[JonasX]

Absolute pish

Ah, a well reasoned and "grown up" response.

I would treat shambolics posts with a pinch of salt.
He had some images of plastic pipe up recently claiming they were eaten by mice when in fact they were probably sabotaged with a grinder.
Ne never did reply to the said post to verify otherwise. Either way it was very suspicious.

Thanks for the warning. He is best ignored.

 

[JonasX]

As a cheap nautral point in a system with several system heat sources they have there place. But that's about it!!

I think you meant neutral. UFH makers use them and they only use one heat source. I suggest you contact one of the makers and get them to give you the low-down on them. Nu-Heat have a stainless pressurized version. It does not need a plumber with a pressurized certificate to fit. They have not experienced any sludge in their thermal stores, even those with rad loops off them.