Valiant/megaflo discharge

[DanDare]

Hi All

Have a megatech HW cylinder heated by a Vailant ecotec 428 boiler.

I've noticed that the boiler's water pressure increases from 1.0bar cold, to 1.6bar when hot - is that normal, or does that indicate a fault with the boilers expansion vessel (for example)

Also, if i turn the HW and CH off for a few days, when I turn back on, a small amount of water is discharged from the system - which could be from the CH/HW system, or possibly from the megaflo heating from cold? - They discharge out of the same pipe.

Perhaps the system is just slightly too full at 1.0bar cold (the boiler is in the attic, at the very top of the system).

Or perhaps this indicates a problem somewhere?

Thanks!

 

[kevplumb]

I've noticed that the boiler's water pressure increases from 1.0bar cold, to 1.6bar when hot - is that normal, or does that indicate a fault with the boilers expansion vessel (for example)

depending on the system volume it sounds normal

 

[doitall]

1.6bar is fine and quite normal when the boiler is hot.

Unless the megaflow is dripping all the time, it could be as you say, just the expansion when heated from cold, I would keep your eye on it. The instruction for expansion should be on the cylinder.

 

[Agile]

For a boiler in the attic 1.0 Bar system pressure is fine. ( 1.5 Bar on ground floor ).

However, thats a large increase to hot and I would suspect either the expansion vessel is undersized or failed.

The internal boiler EXVs are only for a system total volume of about 70 litres. On a normal system the pressure increases by about 0.3-0.4 Bar.

The EXV can be repressurised by following the instructions in the FAQ on this site.

Tony

 

[kevplumb]

However, thats a large increase to hot and I would suspect either the expansion vessel is undersized or failed.

.6 large
expansion vessel failed

drink more coffee

 

[Goldberg]

DanDare - it doesn't matter whether the boiler is in the attic or on the ground floor - the pressure is the same at all points in the system, and the cold pressure should be set according to the MIs. 1.0 bar is likely to be fine, but an increase of 0.6 bar could indicate a problem.

The EV might have failed, but it might simply be down on pressure.

See item #2 on the FAQ topic, here:
//www.diynot.com/forums/viewtopic.php?t=37170

 

[kevplumb]

DanDare - it doesn't matter whether the boiler is in the attic or on the ground floor - the pressure is the same at all points in the system, and the cold pressure should be set according to the MIs. 1.0 bar is likely to be fine, but an increase of 0.6 bar could indicate a problem.

The EV might have failed, but it might simply be down on pressure.

See item #2 on the FAQ topic, here:
//www.diynot.com/forums/viewtopic.php?t=37170

is that load of drivel based on your extensive knowledge of the industry

on account of your job which is

go away goldberk you know nothing

 

[doitall]

An increase of 0.6bar is fine as already said, if anything the expansion vessel may be slightly undersized.

 

[DanDare]

Thanks all for your replies

I'm going to monitor things, and if it continues or gets worse I'll refill the boiler expansion vessel and regenerate the megaflo bubble

Thanks again

 

[Goldberg]

Hi DanDare

The pressure that you've been describing has nothing to do with the Megaflo or its air gap. Whilst it would do no harm to regenerate it, it wouldn't achieve anything.

 

[hedsa]

Is your system a sealed system as the ecotec 428 is an open vent boiler ?

 

[Agile]

The 428 can be fitted to an open vented system but, with the appropriate equipment, it can also be fitted on a pressurised system.

Based on what the OP has described we have to take it that its a a sealed system.

I am surprised that DIA still thinks an increase from 1.0 bar to 1.6 bar is within the realms of "normal".

Either the system is too large for the expansion vessel or it needs recharging in my view.

Tony

 

[DanDare]

Apologies - I don't know where I got 428 from... The boiler is an ECOTEC 624plus.


It's a sealed system.

(I mentioned the megaflo bubble as I'm not completely sure whether the discharge is from the CH/HW circuit, or from the megaflo heating from cold, and they both discharge through the same pipe - see my first post)

 

[Goldberg]

(I mentioned the megaflo bubble as I'm not completely sure whether the discharge is from the CH/HW circuit, or from the megaflo heating from cold, and they both discharge through the same pipe - see my first post)

Fair point, but all you need to do is uncouple the outlet from the CH PRV to see if water is coming from there. Clearly you need to do this when the water is discharging.

 

[kevplumb]

Fair point, but all you need to do is uncouple the outlet from the CH PRV to see if water is coming from there. Clearly you need to do this when the water is discharging.

oh you slay me you really do

if the boiler prv was passing the boiler would be losing pressure

now go play with your toys before you make yourself look

even more stupid