Hello,

Every two weeks, the pressure gauge on our Vaillant ecoTech Plus keeps going down to zero and I have to top up the radiators with more water.

Our plumber has tightened a suspect leaking towel radiator but the pressure still seems to gradually drop over two weeks.

He is going to use Sentinel Leak Fix.

I am not convinced that using this product will completely solve the problem.

Is there anything else that can be checked which may cause the loss of pressure?

M.Joshi inscribed thus:


Hello,

Every two weeks, the pressure gauge on our Vaillant ecoTech Plus
keeps going down to zero and I have to top up the radiators with
more water.

Our plumber has tightened a suspect leaking towel radiator but the
pressure still seems to gradually drop over two weeks.

He is going to use Sentinel Leak Fix.

I am not convinced that using this product will completely solve the
problem.

Is there anything else that can be checked which may cause the loss
of pressure?


--
M.Joshi

I'm not a plumber but if you are loosing water from a sealed system it
has got to be escaping from somewhere. Any joint, soldered,
compression or otherwise is a potential source of escape. You should
carefully inspect every pipe, starting from one end of the system and
working your way round each radiator. Don't forget to check any taps,
drains, or bleeds! Any sign of sweat or moisture could indicate your
leak! The problem is that moisture very quickly evaporates,
particularly if the environment is warm.

Murphy dictates that any leak will be in the hardest place to get
at !! Good Luck.

--
Best Regards:
Baron.

"M.Joshi" wrote in message
...

Hello,

Every two weeks, the pressure gauge on our Vaillant ecoTech Plus keeps
going down to zero and I have to top up the radiators with more water.

Our plumber has tightened a suspect leaking towel radiator but the
pressure still seems to gradually drop over two weeks.

He is going to use Sentinel Leak Fix.

I am not convinced that using this product will completely solve the
problem.

Is there anything else that can be checked which may cause the loss of
pressure?




Can you pressurize the system with air while cold? I've used that trick to
find leaks in automotive cooling systems. I haven't seen radiators used to
heat a house since a few built back in the 1950s but the systems are usually
pretty simple.

Can you pressurize the system with air while cold? I've used that trick to
find leaks in automotive cooling systems. I haven't seen radiators used to
heat a house since a few built back in the 1950s but the systems are usually
pretty simple

That's what I'd do. Figure out how to connect a tire valve into one
of the system's air vents. Then pressurize the whole thing with a
bicycle pump to maybe fifty psi and then go over every joint with
liquid soap and look for bubbles. If you can avoid using the
plumber's sealant stuff, it would probably be better just on general
principles.

It occurs to me that this is the sort of thing I ought to do whenever
I do an extensive plumbing job around he insinuate a Schrader tire
valve into the water system somewhere and whenever I think
everything's going to be just swell, pressurize it to a good hundred
psi with the air compressor and see if it actually is.

M Kinsler

On Jun 18, 5:13 pm, M.Joshi wrote:
Hello,

Every two weeks, the pressure gauge on our Vaillant ecoTech Plus keeps
going down to zero and I have to top up the radiators with more water.

Our plumber has tightened a suspect leaking towel radiator but the
pressure still seems to gradually drop over two weeks.

He is going to use Sentinel Leak Fix.

I am not convinced that using this product will completely solve the
problem.

Is there anything else that can be checked which may cause the loss of
pressure?

--
M.Joshi

Lots of things going on here, and a lot more information is required
in order to diagnose this properly.

How old is the system for one. Not the boiler, but the entire system.

a) What kind of system is this - One or Two pipe?
b) Copper or Iron?
c) Are there any direct copper-to-iron connections?
d) What kind of expansion tank do you have?
e) And have you verified the pressure in it if it is a bladder tank,
or have you drained it recently if it is a water tank?
f) Do you have automatic bleeder valves? If so what kind?
g) Do you have an automatic fill valve?
h) One, two, three-or-more story application?
i) How recent was the boiler installation?
j) How long has this been going on?
k) If this is a vintage system originally, was it sized for gravity or
pump circulator?
l) And how big (how many radiators) is the system overall?

In general, how do you like this little boiler? As I understand it, it
is a gas-fired, stainless steel, wall-hung condensing boiler?

There does happen to be a recall on some Vaillant boilers, have you
checked that? That may be the explanation right there.

DO NOT pressurize the system with air, and most especially DO NOT
pressurize to anything near 50#. First you will blow out the TPR valve
on the boiler, second, you stand to blow out the gaskets in the heat-
exchanger.

If the system is two-pipe, black iron, and sized for a circulator, the
leaks will be at-or-around any new installations you may have made or
had made. This could include the boiler, the towel-warmer radiator or
any other radiators you have installed. It is also possible, but
unlikely that recent installations disturbed an existing joint, or a
knuckle was disturbed for alignment purposes somewhere within the old
piping. This should show pretty obviously.

It is also entirely possible that the system has not been bled
properly (assuming you have automatic bleeders) and what you are
observing is simply the bleeding taking its natural course. It could
also be that you have an undersized expansion tank (a very common
problem if retrofit).

If this is a recently installed all-copper, sweat-connection system,
look for inadequate expansion loops. That can crack a joint or fitting
*just* enough for a tiny leak visible only under pressure.

There are just too many variables to diagnose a problem without
additional information.

Lastly, Miracle-Shyte-Glyte-Leakstop is NOT what you want to install
in any system, especially a high-efficiency copper-based (if that is
what this is) system. It will greatly degrade the heat-exchange
equations going and coming and is altogether a bad idea. Find the
cause of the pressure drop and fix it.

Peter Wieck
Wyncote, PA

DO NOT pressurize the system with air, and most especially DO NOT
pressurize to anything near 50#. First you will blow out the TPR valve
on the boiler, second, you stand to blow out the gaskets in the heat-
exchanger.

Whoops. In that case, I gave bad advice. I'd assumed that this was
like any other plumbing system and would withstand city water
pressure.

M Kinsler

On Jun 19, 11:30 am, m kinsler wrote:
DO NOT pressurize the system with air, and most especially DO NOT
pressurize to anything near 50#. First you will blow out the TPR valve
on the boiler, second, you stand to blow out the gaskets in the heat-
exchanger.

Whoops. In that case, I gave bad advice. I'd assumed that this was
like any other plumbing system and would withstand city water
pressure.

M Kinsler

It happens. Few individuals understand radiant heat anymore. It is a
wonderful system designed properly and can be very efficient as it
puts heat where it does the most good. But, sadly, it does not support
central AC, a major drawback these days.

Peter Wieck
Wyncote, PA

m kinsler inscribed thus:

Can you pressurize the system with air while cold? I've used that
trick to find leaks in automotive cooling systems. I haven't seen
radiators used to heat a house since a few built back in the 1950s
but the systems are usually pretty simple

That's what I'd do. Figure out how to connect a tire valve into one
of the system's air vents. Then pressurize the whole thing with a
bicycle pump to maybe fifty psi and then go over every joint with
liquid soap and look for bubbles. If you can avoid using the
plumber's sealant stuff, it would probably be better just on general
principles.

It occurs to me that this is the sort of thing I ought to do
whenever I do an extensive plumbing job around he insinuate a
Schrader tire valve into the water system somewhere and whenever I
think everything's going to be just swell, pressurize it to a good
hundred psi with the air compressor and see if it actually is.

M Kinsler

Actually, thinking about it, that is a good idea ! The system should
be able to withstand 50 - 100 psi without too much stress. The soap
water trick should work well.

--
Best Regards:
Baron.

DO NOT pressurize the system with air, and most especially DO NOT
pressurize to anything near 50#. First you will blow out the TPR valve
on the boiler, second, you stand to blow out the gaskets in the heat-
exchanger.



Agreed that 50 PSI is way too much, but I don't see a problem with
pressurizing it. When I test automotive cooling systems I pump them up to
about 3 PSI with a bicycle pump, I do this on top of the water already in
there, at which point it will usually drip from the leaky part instead of
coming out as invisible steam.

On Jun 19, 2:31 pm, Baron
wrote:

Actually, thinking about it, that is a good idea ! The system should
be able to withstand 50 - 100 psi without too much stress. The soap
water trick should work well.


Do you know about Hydronic heating systems? Any domestic system that I
know will blow (at least) several gaskets if pressurized to 50#,
possibly more if done so 'dry'. I guess you could tie down or cap the
TPR valve and take your chances, but the other potential is that many
more joints might fail if it is a threaded iron system.

Keep in mind that older systems required pressure only enough to bring
water to the highest point in the system, cold. Normal expansion would
then increase the pressure under operating conditions with water at
anything from ~140F to 180F (60C - 83C) depending on the type of
system and radiator/heat-exchanger design. So, the system would be
provided with an expansion-tank. Some were open and at the top of the
system, some were gravity and at the bottom. Today, pre-pressurized
bladder tanks are used such that they will maintain near-0 content
cold but accept expansion without a significant increase in system
pressure.

We run a system with a 12-meter rise at about 15 psi (1.03bar). When
at operating temperature (140F/60C) pressure increases only to 18psi
(1.24bar), not much considering it is a black-iron two-pipe system.
Just for the sake of clarity, a "two-pipe" system means that each
radiator is the same virtual distance from the boiler, and so each
radiator heats up at the same rate and at the same time. It is easy to
conceive: Draw two parallel lines, label one "supply and the other
"return". The individual radiators cross from the one side to the
other. Now, draw a line from the SUPPLY side on the right to a box.
And from the RETURN SIDE on the left to the same box. Label the box
"Boiler". You can see that the radiator closest on the supply side is
furthest on the return side, and vice-versa. The one in the middle is
equi-distant. That is how it works. Our TPR valve is set for 30psi/
200F. Some margin, but not a huge amount nor would we want it so.

Most modern installed systems are simple loops. The radiator closest
to the supply heats first. The guy last in line gets short shrift.

Peter Wieck
Wyncote, PA

inscribed thus:

On Jun 19, 2:31 pm, Baron
wrote:

Actually, thinking about it, that is a good idea ! The system
should
be able to withstand 50 - 100 psi without too much stress. The
soap water trick should work well.


Do you know about Hydronic heating systems? Any domestic system that
I know will blow (at least) several gaskets if pressurized to 50#,
possibly more if done so 'dry'. I guess you could tie down or cap
the TPR valve and take your chances, but the other potential is that
many more joints might fail if it is a threaded iron system.

Keep in mind that older systems required pressure only enough to
bring water to the highest point in the system, cold. Normal
expansion would then increase the pressure under operating
conditions with water at anything from ~140F to 180F (60C - 83C)
depending on the type of system and radiator/heat-exchanger design.
So, the system would be provided with an expansion-tank. Some were
open and at the top of the system, some were gravity and at the
bottom. Today, pre-pressurized bladder tanks are used such that they
will maintain near-0 content cold but accept expansion without a
significant increase in system pressure.

We run a system with a 12-meter rise at about 15 psi (1.03bar). When
at operating temperature (140F/60C) pressure increases only to 18psi
(1.24bar), not much considering it is a black-iron two-pipe system.
Just for the sake of clarity, a "two-pipe" system means that each
radiator is the same virtual distance from the boiler, and so each
radiator heats up at the same rate and at the same time. It is easy
to conceive: Draw two parallel lines, label one "supply and the
other "return". The individual radiators cross from the one side to
the other. Now, draw a line from the SUPPLY side on the right to a
box. And from the RETURN SIDE on the left to the same box. Label the
box "Boiler". You can see that the radiator closest on the supply
side is furthest on the return side, and vice-versa. The one in the
middle is equi-distant. That is how it works. Our TPR valve is set
for 30psi/ 200F. Some margin, but not a huge amount nor would we
want it so.

Most modern installed systems are simple loops. The radiator closest
to the supply heats first. The guy last in line gets short shrift.

Peter Wieck
Wyncote, PA

Thankyou for your notes. I did say up front that I was not a plumber!
However I do understand what you are saying and appreciate it. I can
see why pressurising a system in the way described is not a good
idea. I withdraw my comment unreservedly.

--
Best Regards:
Baron.

On Jun 19, 3:41 pm, Baron
wrote:

Thankyou for your notes. I did say up front that I was not a plumber!
However I do understand what you are saying and appreciate it. I can
see why pressurising a system in the way described is not a good
idea. I withdraw my comment unreservedly.


As I have written before, hydronic systems are nearly a lost art in
domestic applications. I have installed two in my time and repaired
MANY, and I am perhaps the youngest person (at 55) that I know not a
professional plumber or engineer that has any clue about their general
operation. But I have lived in two houses with such systems, both over
100 years old, both retro-fitted from either stove/fireplace or coal-
fired octopus systems to hydronics in the '30s. Self-defense has made
me quite familiar with their vagaries.

Peter Wieck
Wyncote, PA

"M.Joshi" wrote in message
...

Hello,

Every two weeks, the pressure gauge on our Vaillant ecoTech Plus keeps
going down to zero and I have to top up the radiators with more water.

Our plumber has tightened a suspect leaking towel radiator but the
pressure still seems to gradually drop over two weeks.

He is going to use Sentinel Leak Fix.

I am not convinced that using this product will completely solve the
problem.

Is there anything else that can be checked which may cause the loss of
pressure?

Are you sure that water is not leaking through the pressure release valve?
It sometimes evaporates and leaves no evidence.
Can you temporarily connect a hose and a container to catch any water
leaking from the pressure release valve pipe which exits outside the
buliding.

Rudge.

Thank you all for your replies.

Firstly, in response to your first post Peter:

"How old is the system for one. Not the boiler, but the entire system."
Originally we had a gravity fed system fitted about 30 years ago with a cold water tank in the loft and a hot water storage tank below. This system was recently replaced by a Megaflo tank and Vaillant condensing combi boiler. As this is a pressurised system the cold water storage tanks were no longer requried. We replaced some of the radiators with newer ones and additional ones were added including a towel radiator.

a) What kind of system is this - One or Two pipe?
I believe two pipe - Separate water and heating pipes.
b) Copper or Iron?
Copper
c) Are there any direct copper-to-iron connections?
I don't think so?
d) What kind of expansion tank do you have?
None
e) And have you verified the pressure in it if it is a bladder tank,
or have you drained it recently if it is a water tank?
N/A
f) Do you have automatic bleeder valves? If so what kind?
Manual bleeder valves on the radiators. An automatic bleeder valve on the Megaflo tank I believe?
g) Do you have an automatic fill valve?
Manual filling loop to pressurise the system
h) One, two, three-or-more story application?
Two storey
i) How recent was the boiler installation?
A few months
j) How long has this been going on?
SInce it was installed
k) If this is a vintage system originally, was it sized for gravity or
pump circulator?
Gravity - pump
l) And how big (how many radiators) is the system overall?
10
In general, how do you like this little boiler? As I understand it, it
is a gas-fired, stainless steel, wall-hung condensing boiler?
It is supposed to be a good reliable boiler. Hard to comment on performance as we have only had it installed for a few months.

"Rudge, in answer to your question:
Are you sure that water is not leaking through the pressure release valve?
It sometimes evaporates and leaves no evidence.
Can you temporarily connect a hose and a container to catch any water
leaking from the pressure release valve pipe which exits outside the
buliding.

Rudge."


I don't think any of the radiator bleeders are leaking. The only leak I spotted was on the towel radiator valve which was tightened by the plumber.

I have noticed a stream of water escaping from the flue while the boiler is operating which I find rather strange?

Thanks.

In article ,
Rudge wrote:
Can you temporarily connect a hose and a container to catch any water
leaking from the pressure release valve pipe which exits outside the
buliding.

I have also seen the PRV fail. The spring weakens slightly. It holds the
pressure when cold and topped up even to 3 bar when we tested it but weeps
slightly in service so the pressure drops slowly over several days when in
use.

HTH

--
Mitch


www.sand-hill.freeserve.co.uk/terminal_crazy

On Jun 20, 6:55 pm, M.Joshi wrote:

I have noticed a stream of water escaping from the flue while the
boiler is operating which I find rather strange?

A couple of things first:

a) Condensing boilers exhause either 'steam' or steam with a small
stream of water. That is their nature and not of concern. The chemical
reaction is 2CH4 + 3O2 = 2CO2 + 4H2O or, lots of water.

b) "Two-Pipe" system relates to how the radiators are fed. A loop-
system puts the radiators on a loop such that the radiator nearest the
boiler sees hot water first, then the next and the next until the
entire system equalizes, excepting that the last radiator in the line
is always coolest. A "Two-Pipe" system sets up parallel supply and
return lines such that all the radiators "see" the boiler at the same
distance. The first radiator on the supply side is the last on the
return side, the last on the supply-side is first on the return side.
This system heats all the radiators at the same rate simultaneously
and is the most efficient except that it requires 50% more pipe and
very careful planning/engineering as compared to a loop system.

c) I am gathering that your system provides domestic hot water as well
as heating water, and so here in the US, we would call it a "summer/
winter hook-up". That is quite an elegant use of these boilers, about
the only thing more efficient than such a system would be some of the
tankless instant-hot water-systems.

But, cutting to the chase, somewhere, some how, there *must* be an
expansion-tank. Your Megaflo tank is simply a heat-exchanger loop from
the boiler to a domestic hot water storage tank, and most emphatically
*NOT* an expansion tank. The bleeder is for the domestic water side,
not the central heat side.

If you do not have an expansion-tank within the system, may I gather
that you have not yet used it for heat in the winter? Because when you
do, you will absolutely blow off the TPR valve, which if not vented
outside will be a hot, smelly mess on top of which you risk boiling
out your system otherwise. And, this is absolutely the source of your
pressure drop. The system is over-pressurizing each cycle and either
venting through the valve slowly or at some hidden fitting.

Please check again for an expansion tank. With only ten radiators, it
may be as small as a football (soccer ball, for the US) and hidden in
some corner somewhere. If you have one, make sure that it is properly
pressurized and/or properly drained (if from the old system). If it is
a bladder-tank there will be a Schrader-valve on it that you may check
with a tire pressure gauge and charge with a bicycle tire pump. For 2
stories, charge it to about 12psi... and MAKE SURE it holds at that
pressure.

An all-copper system only 30 years old would not be gravity. Gravity
systems use VERY fat pipe on the return side relative to the supply
side and special valves such that expanding (freshly heated) water
pushes through the valve causing flow. They are typically designed
against standing-pilot systems with millivolt-pile thermostats run
from electricity generated by the pilot through a thermocouple. These
were designed for areas where mains power either did not exist or was
unreliable. Very elegant, very simple. Not terribly efficient by
modern standards.

Peter Wieck
Wyncote, PA