Bypass when using Grundfos Alpha2 pump

[D_Hailsham]

But some current boilers do not have pump overrun. So how does the heat exchanger get cooled down?

Name a boiler model and we will comment on it !

Baxi Solo OV boilers.

If you have an S or Y plan with a room stat the pump is connected to the switched live (so no overrun) and a bypass can be fitted but is not required - even for an S Plan.

The pump only needs to be connected to the boiler (to provide overrun) if you have a fully TRV'd system; and a bypass is not permitted.

 

[matt1e]

Immediately combustion ceases the inside of the combustion chamber is at about 500 C and glowing whitish red hot! It takes about 5-10 seconds for most of the glow to disappear. Glowing only occurs at a few hundred degrees. During this time AND for a while afterwards this heat has to be removed by the water flow!

But some current boilers do not have pump overrun. So how does the heat exchanger get cooled down?

they are cooled by the standing water in them (if there is enough of it) and natural cooling
its usually low water content boilers that req pump overrun for reasons that agile has already given
basically wether pump overrun is req is determined by
a)the material the hex is made of
and
b)the amount of water it holds

Matt

 

[smokebox]

Immediately combustion ceases the inside of the combustion chamber is at about 500 C and glowing whitish red hot! It takes about 5-10 seconds for most of the glow to disappear. Glowing only occurs at a few hundred degrees. During this time AND for a while afterwards this heat has to be removed by the water flow!

But some current boilers do not have pump overrun. So how does the heat exchanger get cooled down?

its usually low water content boilers that req pump overrun for reasons that agile has already given
basically wether pump overrun is req is determined by
a)the material the hex is made of
and
b)the amount of water it holds

Matt

Matt
Makes sense

smokebox.

I have learned so much on this thread.

Thanks to all you expert contributors!

Agile was actually quite right. I started like a know all pri*k. but soon began to be humbled quite a bit!

I beleive with your collective help, especially Hailsham, Agile, and Matt, and your tolerance in sticking with me that I have actually come up with a slightly better and more economical of gas and electricity solution.

I shall get a bit better I hope, ( home from hospital) and execute the plan of an electrically controlled bypass.

I shall report in due course. I will also need a bigger Alpha2 which is a pest.

smokebox

 

[MJN]

Name a boiler model and we will comment on it !

Ideal Icos is one. It's cooled by means of the fan.

Mathew

 

[Dan Robinson]

Intergas/Atmos OV Range.

 

[gaswizzard]

Whether the burner is @ part load or full load will make little difference regards minimum flow rate through hex , the 'glowing embers' you are seeing through the viewing window are certainly NOT the Hex.

Most of the latent heat in the hex is removed by the fan. (premix)

 

[gaswizzard]

If you could then I would suggest that you would find it frightening to look closely at the viewing window when I turn the boiler on. I could almost place a bet you will recoil from the sight ( and the radiated heat ! ).

Frightening?

Does anyone have a video to show him? Its not as impressive as looking yourself though! Until someone finds a better video try this one although there is a combustion fault! http://www.youtube.com/watch?v=gf0-EJL07i4[/QUOTE]

What is the point of that video? , seems to me as if the 'engineer' is deliberately restricting combustion air to fan , shame it didn't focus on the FGA for long enough to show a fuel rich condition.

CO2/COppm is what would be expected so what was the point in this video?

 

[smokebox]

gass wizard

Read the previous few contrbutions, to put it in context.
Remember we are not all gas registered men, and some of us are interested in learnibg about boilers etc - not neccessarily gas safe fixing type work.

A broad mind can be a wiser mind.

smokebox

 

[gaswizzard]

gass wizard

Read the previous few contrbutions, to put it in context.

I have Smokebox & some of it is just BS.

D Hailsham puts a lot of good info into this forum only to be ridiculed , it's the 'look at me i'm a RGI' that spoils these type threads.

Smokebox , seems your thanking the wrong guys on here.

 

[Agile]

Glad to see you are back in the land of the living, perhaps with an ( auto ) heart bypass!

Go easy on the amyl nitrite!

 

[smokebox]

gass wizard

Read the previous few contrbutions, to put it in context.

I have Smokebox & some of it is just BS.

D Hailsham puts a lot of good info into this forum only to be ridiculed , it's the 'look at me i'm a RGI' that spoils these type threads.

Smokebox , seems your thanking the wrong guys on here.

I'll quietly accept I am an unregistered RGI man, I will not accept I am speaking BS! Tell me which other BS is worrying you.

I am thanking the guys who have maintained an intelligent, timely and helpful approach. I don't know for sure who is and who is not RGI. but I have the fortune to possess a very considerable brain with some scientific training, and use it to analyse and make deductions about contributions and contributors. Firing from the hip is dangerous - you can hit your feet, or worse! Anger can be so counterproductive sometimes.

It is not an evil thing to be unregisterd, or is it in your view?

smokebox

 

[Agile]

It IS evil to do gas work when unregistered!

Oddly this site objected to those who were gas registered putting a Gas Safe logo after their name. I dont know why!

Tony

 

[smokebox]

It IS evil to do gas work when unregistered!

Oddly this site objected to those who were gas registered putting a Gas Safe logo after their name. I dont know why!

Tony

I agree with that wholeheartedly. It is also the law.

smokebox

 

[gaswizzard]

Smokebox , my comments were not aimed at your goodself.

 

[JonasX]

It IS evil to do gas work when unregistered!

Oddly this site objected to those who were gas registered putting a Gas Safe logo after their name. I dont know why!

Tony

I agree with that wholeheartedly. It is also the law.

smokebox

1. GasSafe is for people who make money from working with gas.
2. A Competent DIYer can work on a system as long a he is not receiving money.

That is the LAW!
Competence does not mean having a paper certificate or registration.

Smokebox, if you are competent to work on your own kit you can.

A retired gas fitter who is not registered can freely work on his own kit or anyone else's, as long as he does not receive money - in short make a living from it. According to this Agile chap, he is evil for doing so.