Calorifier

[Batavia]

Wow, 250 posts they must be very clever things these 'ere Glorifiers.

And I have not even got one - must remember to ask for one for Christmas (if it will fit down the chimney).

[RLWP]

Wow, 250 posts they must be very clever things these 'ere Glorifiers.

 

Actually, I think two of them are more complex self-glorifiers.

 

Richard

[chris w]

And I have not even got one - must remember to ask for one for Christmas (if it will fit down the chimney).

Not if you get one from TerryLicense(sic). He's recommending above the 1 cu ft model............................

 

We were not talking about boats.

 

It may have escaped that pea-sized brain of yours but I suspect that you're not on the right Forum

 

No doubt you thought this was the tractor site from "Sheep Sh*ggers Monthly" of which, I understand, you are President Emeritus

[Guest TerryL]

Chris W, have you read post #228?

 

Do you understand how EV's work now?

 

cheers,

Pete.

I think this is a lost cause Pete, he can waffle and make the finer points seem complicated but can't get his head around the basics. He can't see through his own "run the maths" smokescreen, so everyone else is wrong! Do I care?

[chris w]

Chris W, have you read post #228?

 

Do you understand how EV's work now?

 

cheers,

Pete.

The point I am belabouring is that my 8 litre EV, set to 36psi, will absorb 2 litres of water (based on thermal expansion of water coefficients) when the calorifier is at 85degC. By Boyle's Law, that makes the EV pressure 48psi which is way over the PRV pressure. Yet the PRV stopped dribbling the moment I fitted the EV. I am trying to reconcile those two figures rather than just accepting something without at least some experimentation. No-one on here has offered a plausible explanantion for that apparent contradiction yet, other than "system anomalies"!

 

I have ordered two pressure gauges with which I shall monitor calorifier pressure and EV pressure continuously to see what is actually happening when the water heats up. From the EV pressure change measurements, I should be able to ascertain the exact amount of water expansion at various temperatures and be able to monitor exactly the calorifier pressure changes. I also intend to fit an isolation valve in order to be able to have the EV in or out of circuit. Further, I shall also know exactly the WP's cut-in and cut-out pressures rather than just relying on the manufacturer's figures.

 

That should be enough data to be able to carry out a proper mathematical analysis.

Edited November 12, 2008 by chris w

[Guest TerryL]

The point I am belabouring is that my 8 litre EV, set to 36psi, will absorb 2 litres of water (based on thermal expansion of water coefficients) when the calorifier is at 85degC. By Boyle's Law, that makes the EV pressure 48psi which is way over the PRV pressure. Yet the PRV stopped dribbling the moment I fitted the EV. I am trying to reconcile those two figures rather than just accepting something without at least some experimentation. No-one on here has offered a plausible explanantion for that apparent contradiction yet, other than "system anomalies"!

 

I have ordered two pressure gauges with which I shall monitor calorifier pressure and EV pressure continuously to see what is actually happening when the water heats up. From the EV pressure change measurements, I should be able to ascertain the exact amount of water expansion at various temperatures and be able to monitor exactly the calorifier pressure changes. I also intend to fit an isolation valve in order to be able to have the EV in or out of circuit. Further, I shall also know exactly the WP's cut-in and cut-out pressures rather than just relying on the manufacturer's figures.

 

That should be enough data to be able to carry out a proper mathematical analysis.

I think Gibbo hit the nail on the head when he mentioned the trapped air in horizontal calorifiers. A Surecal calorifer will have a lot of wasted capacity, a bit like your head really!

[RLWP]

I have ordered two pressure gauges with which I shall monitor calorifier pressure and EV pressure continuously to see what is actually happening when the water heats up.

 

To check my understanding - by the EV pressure, are going to measure the gas pressure in the air side of the EV? Perhaps with something like a tyre pressure gauge?

 

Richard

 

I'm looking forward to you results.

[chris w]

To check my understanding - by the EV pressure, are going to measure the gas pressure in the air side of the EV? Perhaps with something like a tyre pressure gauge?

 

Richard

 

I'm looking forward to you results.

Yes, but I shall have a permanent (professional) pressure gauge attached. The other I intend to fit in the hot water outlet pipe adjacent to the PRV.

 

Chris

[Guest TerryL]

Yes, but I shall have a permanent (professional) pressure gauge attached. The other I intend to fit in the hot water outlet pipe adjacent to the PRV.

 

Chris

Do you ever get out Chris? Your millions are wasted on you, tell you what, you do my job and I'll spend your money!

Edited November 12, 2008 by TerryL

[RLWP]

Do you ever get out Chris?

 

How is this comment helpful?

 

Richard

[chris w]

I think Gibbo hit the nail on the head when he mentioned the trapped air in horizontal calorifiers.

 

That's strange.... back in post #101 you disagreed with Gibbo's theory stating that the air would get "absorbed". For the record, I have a vertical calorifier anyway so no air can be trapped in that dumbwit.

[wonderdust]

How is this comment helpful?

 

Richard

 

And the other 250 odd have been?

[Guest TerryL]

How is this comment helpful?

 

Richard

It's no more helpful than yours apart from the point.

 

 

That's strange.... back in post #101 you disagreed with Gibbo's theory stating that the air would get "absorbed". For the record, I have a vertical calorifier anyway so no air can be trapped in that dumbwit.

Did you install it the right way up? You might have got some hot air in it!

[chris w]

Do you ever get out Chris? Your millions are wasted on you, tell you what, you do my job and I'll spend your money!

The reason that you don't have millions is that you're always on here rather than working.

 

If you're such a good "plummer" etc how is it you have no work to do and can idle your time on here all day?

 

Maybe I'll book you for a job - I know the number

[ChrisPy]

not arf !

[Guest TerryL]

The reason that you don't have millions is that you're always on here rather than working.

 

If you're such a good "plummer" etc how is it you have no work to do and can idle your time on here all day?

 

Maybe I'll book you for a job - I know the number

It's called multi tasking and I can also have time off when I please to amuse myself reading your efforts. Our operators are waiting for your call.

 

It's "plumber" Chris.

[Denis R]

Right, I've just gone back through this entire thread and by filtering out the NVA posts have, I think, an idea of what I need. Here goes (God knows why....)

My system has a FloJet pump with built in cross-port relief (designed to minimise pump pulsation, so they say. It seems to work.) FloJet state that an accumulator must NOT be fitted to the circuit because of this built in system. However, I too suffer the dribbling PRV syndrome and the first PRV failed open due to scale build up after 2 years. The pump cut-out pressure is 2,0 Bar I believe. The PRV rating is 3,0 Bar. There is currently no NRV in the system and the 80 odd litre calorifier does not back-feed hot water into the cold.

I would propose to fit a NRV in the cold water feed close to the calorifier and between the NRV and calorifier, tee in an 8 litre EV pre-charged to whatever pressure that link to the calculator calculates.

Did I get it right?

[ChrisPy]

The point I am belabouring is that my 8 litre EV, set to 36psi, will absorb 2 litres of water (based on thermal expansion of water coefficients) when the calorifier is at 85degC. By Boyle's Law, that makes the EV pressure 48psi which is way over the PRV pressure.

INCREDIBLE ........... you still don't understand the difference between absolute pressure and gauge pressure!

 

or perhaps your head is so far up your own ........... with all your 'belabouring' that you can't be arsed to read and understand technical explanations presented by others.

 

from crispy-'PRAT' :lol:

 

 

................ Catweasel .... any space on top of Anderton?

[Batavia]

................ Catweasel .... any space on top of Anderton?

 

Just make sure that you have the appropriate BW licence for what you have in mind ...

[RobinJ]

My system has a FloJet pump with built in cross-port relief (designed to minimise pump pulsation, so they say. It seems to work.) FloJet state that an accumulator must NOT be fitted to the circuit because of this built in system. However, I too suffer the dribbling PRV syndrome and the first PRV failed open due to scale build up after 2 years. The pump cut-out pressure is 2,0 Bar I believe. The PRV rating is 3,0 Bar. There is currently no NRV in the system and the 80 odd litre calorifier does not back-feed hot water into the cold.

I would propose to fit a NRV in the cold water feed close to the calorifier and between the NRV and calorifier, tee in an 8 litre EV pre-charged to whatever pressure that link to the calculator calculates.

Sounds about right, pump at around 30 psi, NRV, expansion vessel set to about 35 psi, it should accomodate the 3l or so after heating, the PRV will still leak it expands more than about 3.5l as the pressure will be pretty close to 45psi.

[Denis R]

Thanks Robin,

Just checked to make sure and the pump cut-out pressure is actually 2,5 Bar so there's not a lot of margin. Assuming I'm using Smileypete's calculator link correctly and their 'vessel operating pressure' equates to the PRV pressure, it gives me a pre-charge pressure of 2,8 Bar based on that PRV setting of 3 Bar. Expanded volume worked out at 3,64 litres and resulting pressure in the EV of 5,97 Bar. All this is based on 85 Deg water temp heated from the engine circuit and 10 Deg feed water. Go 0 - 100 Deg and an 8 litre EV isn't big enough.... Tight?

[Guest]

Catweasel

 

I tried to reply to your PM but it said you were "uncontactable" (you've probably got me blocked)

 

Let me know when it's OK to send my reply.

 

Cheers

 

Chris

I had everybody blocked who has ever sent me a message!! How did I do that? I am sure I have never altered any settings? Should be OK now. BTW your inbox is full Chris.

 

Cheers

[chris w]

I had everybody blocked who has ever sent me a message!! How did I do that? I am sure I have never altered any settings? Should be OK now. BTW your inbox is full Chris.

 

Cheers

It's done Catweasel

[smileypete]

Just checked to make sure and the pump cut-out pressure is actually 2,5 Bar so there's not a lot of margin. Assuming I'm using Smileypete's calculator link correctly and their 'vessel operating pressure' equates to the PRV pressure, it gives me a pre-charge pressure of 2,8 Bar based on that PRV setting of 3 Bar. Expanded volume worked out at 3,64 litres and resulting pressure in the EV of 5,97 Bar. All this is based on 85 Deg water temp heated from the engine circuit and 10 Deg feed water. Go 0 - 100 Deg and an 8 litre EV isn't big enough.... Tight?

'Vessel operating pressure' should be set to pump cut-out pressure.

 

'Vessel precharge pressure' can be set the same as pump cut-out pressure too, to give maximum expansion.

'Security valve pressure' is PRV release pressure, which is almost always 3 bar.

 

Edit: Pump cut out pressure looks pretty high at 2.5 bar, is it really that high and if so is it adjustable down to say 2.0 bar? Otherwise you'll need a pretty big expansion vessel.

 

cheers,

Pete.

Edited November 12, 2008 by smileypete

[chris w]

INCREDIBLE ........... you still don't understand the difference between absolute pressure and gauge pressure!

 

or perhaps your head is so far up your own ........... with all your 'belabouring' that you can't be arsed to read and understand technical explanations presented by others.

 

from crispy-'PRAT' :lol:

 

 

................ Catweasel .... any space on top of Anderton?

Dear Crispy Prat

 

Run the same example I used in absolute pressure terms.

 

8 litre EV set at 35psig (50psia)

Pump cut-out = 30 psig (45psia)

Calorifier size 60 litres

Water expansion 2 litres

PRV 42psig

 

When the pump cuts out at 45psia, the air volume of the EV doesn't change (ie: remains at 8 litres) because the EV's absolute pressure (50psia) is higher than the pump's cut-out absolute pressure (45 psia).

 

When, due to heating, the calorifier water expands by 2 litres, the EV air volume reduces to 6 litres and its pressure therefore increases to 8 x 50 / 6 =67 psia or 52 psig. Since the PRV's blow pressure is 42psig, the water should be p*ssing out of the PRV (as I stated before) but it's not (as I stated before). So there is still something that you (and I) are not taking into account.