Vokera mynute 25 HE - leak.

Thierry

Got this Vokera mynute 25 HE about 6 years ago.

Since last service (back in October 2015), the pressure has been dropping. I had to refill times to times with silver loop and black tap.
But since January the pressure would fall very rapidly, like overnight. So I had to leave the filling loop open to get pressure.

The service engineer told me that I must have a leak somewhere in the house. So I have inspected every single radiator and pipes... no visible leak.

Yesterday, the boiler would not fire up, red light turn on after 30 seconds attempt. Pressure looping circuit on.

RGII engineer came; as there was water coming out the condensing trap from the heatexchanger, he said the heathexchanger must be faulty and need replacement.

He also said that this model is poorly design and this is a common problem.
So I have two options:
- replace the heathexchanger - cost about €380 with Vokera
- replace the boiler all together - some estimates around €1800.

Considering the boiler is only 6 years old, I am going to replace the faulty part. Would you agree?
Also, do I need to put some inhibitor in the radiator circuit, as the leak would have remove most of it, while fresh water was coming as the filling loop was open to get pressure up. How do I do this?

K.Flyer

Whoever called should have been able to tell if the heat exchanger is leaking or not leaking, no "might be". On some models there is a auto vent valve which has a tube to the condensation trap, this may be faulty and allowing water to pass.
I would suggest having the new parts fitted if that is all that is wrong with the boiler and it is generally in good condition. I would also suggest having a magnetic filter added to the pipework while you are at it as this will provide you with a point for topping up the sysem with inhibitor. If the system is dirty with a lot of dark black water, then you need to have the system cleaned before you do anything.

DGOBS

Simple test, pressurise system to 1 bar, and close your filling loop, close both water isolating valves under the boiler, leave for 12-24 hours.
If water gauge on the boiler falls, then you have just proven the leak is on the boiler (not your heating circuit)
If the pressure doesn't fall, the open both valves again under boiler, if the pressure instantly falls, you have proven the leak is on you central heating circuit.

Also, if there is water coming out of your condensate pipe even when the boiler is off, then there is a leak in the boiler heat exchanger.

Of course...do not use your boiler with the valves isolated, make sure to turn of your programmer

Thierry

thanks K.Flyer and DGOBS.

<<Also, if there is water coming out of your condensate pipe even when the boiler is off, then there is a leak in the boiler heat exchanger.>>

that's what the engineer saw. The condensing pipe going into the little box and then outside was leaking even after 2 hours the heather was off.

Thierry

About how to add inhibitor...

I found this link: http://www.sentinelprotects.com/uk/support/guides/how-dose-inhibitor-and-cleaner-central-heating-system
But I am not sure if I have an open system or sealed system... I know the heather is combi (does hot water and heating).
There is a filling loop in the hot press to refill the system when the pressure goes down at the heather gauge.
But I doubt that I can use this point to add inhibitor? can I?


After the Vokera engineer will have replace the heathexchanger (as it was leaking), should I get a plumber to clean the system or/and add inhibitor?

K.Flyer

If you want to get the best from the heat exchanger get it done as soon as possible. If you leave it as it is, it would be like putting old oil into a new engine.

Thierry

Condensing tank was pierced and was leaking onto the heat exchanger return pipe. That pipe corroded and was leaking. That was the first problem (leak and dropping pressure).

Vokera engineer replaced condensing tank and pipe (new pipe in copper, old one was a silver colored metal...).

Ignition electrode and transformer were also replaced as heather did not ignite.

257 euros for the whole lot and that fixed it for now.

Will let you know if that does not fix it!

Thierry

19th March 2016 -
Boiler is working, in terms of producing hot water and heating the rads.

However, there is still the problem of water pressure loss, and it is quite bad: once the feeding loop is closed the pressure goes from 1 bar to 0 in few hours (3 or 4 hours).At 0 bar, the heater does not ignite. Realistically, it means that the system cannot work unless the feeding loop is open. Leaving the feeding loop open all the time, without dealing with probable water loss would cause other issues I have read.
- I assume the feeding loop is connected indirectly to the radiator circuit through the heater ; the inhibitor put in the radiator circuit will run out as fresh water is put into the system. Fresh water will eventually cause corrosion of components.

So the question remains: what cause the pressure loss? There is some pressure difference between water hot and cold, but not to explain one bar difference. Only one explanation: water loss.
So where is the leak?

The only leak I can see is coming from the condensing drain (outside). I believe this is normal when the heater is on, as the excess condensation needs to be drained. But once the heater is not working and condensation is extracted. there should not be any leak from there.

The heater is not working overnight, so let's close the feeding loop at 9:00 pm
- 00:00 am: after 3 hours, the pressure is down to 0. There is still water coming through the condensation drain: about one drop per 2 seconds. I had put a container (500ml) to collect the water: it is full after that time, overflowing. Water has a rusty color.
- 7:30 am next day: sounds of pump clicking at the water return flow inside the boiler. Timers are still off (water and rads) , feeding loop still closed and it is cold in the house. Water has stopped leaking outside.
- 7:35 am: open the feeding loop. Water goes into the boiler and the sound of clicking pump stops.
- 7:50 am: Water starts to drip out at the condensation drain. Rate is slower (about a drop every 5 seconds), and I have collected the water (clear water, no rusty color). Heater is still off.
- 8:30 am: brought coffee/.hot chocolate and toasts in bed to wife and kid. Got some brownie points...
- 10:00 am: lost my brownie points, as wife complains the house is cold. 200 mm of clear water has dripped from condensing drain, with heater off and feeding loop on.
- Turn the heat on. Boiler ignites normally ans house is getting warm.

What should I do here, any advice?

from DGOBS: <<Simple test, pressurise system to 1 bar, and close your filling loop, close both water isolating valves under the boiler, leave for 12-24 hours.>>

I cannot see any valves, or I don't know how to close the valves under the boiler. But I believe the tests related above, prove the same thing?

Dtp1979

Take a picture of the underneath of the boiler and post it. Also, is the hot water cylinder located upstairs or downstairs?

K.Flyer

Thierry wrote: »

Condensing tank was pierced and was leaking onto the heat exchanger return pipe. That pipe corroded and was leaking. That was the first problem (leak and dropping pressure).

The conveyor was leaking (common problem) and dripping onto the return pipe.
That doesn't explain how the water was getting out through the condense trap / drain.
Sounds to me that you had two problems and whoever looked at it missed the other one.
You need to get them back.
I would also be reluctant to close the service valves on that boiler as the seals on the valve can sometimes leak and the valves would then need to be replaced.
If you are still getting water dripping out through the condense drain then the issue has not been resolved.
Either the auto air vent just off the heat exchanger is letting water pass and the water is getting into the condense trap via a narrow tube.
Or the heat exchanger is leaking internally.
My money is on the vent valve.

Thierry

Dtp1979 wrote: »

Take a picture of the underneath of the boiler and post it. Also, is the hot water cylinder located upstairs or downstairs?

Here is the picture.

Thierry

K.Flyer wrote: »

The conveyor was leaking (common problem) and dripping onto the return pipe.
That doesn't explain how the water was getting out through the condense trap / drain.
Sounds to me that you had two problems and whoever looked at it missed the other one.
You need to get them back.
I would also be reluctant to close the service valves on that boiler as the seals on the valve can sometimes leak and the valves would then need to be replaced.
If you are still getting water dripping out through the condense drain then the issue has not been resolved.
Either the auto air vent just off the heat exchanger is letting water pass and the water is getting into the condense trap via a narrow tube.
Or the heat exchanger is leaking internally.
My money is on the vent valve.

Thanks K>Flyer. Will ring Vokera first thing tomorrow morning.
At least I know what arguments I can put forward, in case they come back and tell me that it must be in the radiator circuit.
Attached in the pic of pipe and conveyor before replacement.

K.Flyer

Thierry wrote: »

Thanks K>Flyer. Will ring Vokera first thing tomorrow morning.
At least I know what arguments I can put forward, in case they come back and tell me that it must be in the radiator circuit.
Attached in the pic of pipe and conveyor before replacement.

Do you have any other pics of around the inside of the boiler, can you put them up.
Some have the tube from the auto vent, some don't, it would be interesting to see other pictures if you have them.

Thierry

K.Flyer wrote: »

Do you have any other pics of around the inside of the boiler, can you put them up.
Some have the tube from the auto vent, some don't, it would be interesting to see other pictures if you have them.

I have attached a few.
You may also look at the instructions manual (pdf attached). Page 1 there is a diagram of inside. Mine is the Vokera mynute 25HE> top drawing.
Sorry the file is too big to be uploaded here, but you can grab it at:
https://www.google.ie/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwihot3MvNHLAhVEfA4KHcVLBLYQFggcMAA&url=http%3A%2F%2Fcdn0.vokera.co.uk%2Fwp-content%2Fuploads%2F2009%2F04%2Fmynute-he-installation-and-servicing-manual.pdf&usg=AFQjCNEwCdQLNO2zDiWoz5HmsEhaTCexgQ&sig2=fc9plyl9pIcQak3UVY753g

Thierry

Dtp1979 wrote: »

Take a picture of the underneath of the boiler and post it. Also, is the hot water cylinder located upstairs or downstairs?

The hot cylinder is on the ground floor, same as the boiler about 6 meters away and below level of the boiler.


Rang Vokera and explained the issue.
They are sending their engineer back this week, to have a look. Good thing is labor from the first visit is guaranteed for a month! and parts for a year.

K.Flyer

Ok, yours does not have the tube connection to the aav as you can see the small black cap on the condense trap.
Underneath the boiler you have a white condense drain pipe and a thin 1/2" copper pipe.
Are both of them visible on the outside of the wall?

Thierry

K.Flyer wrote: »

Ok, yours does not have the tube connection to the aav as you can see the small black cap on the condense trap.
Underneath the boiler you have a white condense drain pipe and a thin 1/2" copper pipe.
Are both of them visible on the outside of the wall?

Yes, both go outside.

K.Flyer

Ok, just checking that they are not T'eed into each other.
If you still have a continuous flow of dripping water out through the condense drain pipe hours after the machine has been turned off for a few hours, it would most likely lead back to the heat exchanger.

Thierry

Ok, Heat exchanger has been replaced. No leak anymore at the condensing pipe outside - even when the heater is on!! Will check again tomorrow morning, but the pressure is not dropping anymore (that's after 3 hours the job was completed).
Total cost so far: €380 for all.
The only thing with Vokera, they did not take the old part!

I need to get my radiator circuit cleaned/flushed and inhibitor added. What price are we talking for this? It is a 3-bedroom house, with 10 radiators?

Dtp1979

Thierry wrote: »

Ok, Heat exchanger has been replaced. No leak anymore at the condensing pipe outside - even when the heater is on!! Will check again tomorrow morning, but the pressure is not dropping anymore (that's after 3 hours the job was completed).
Total cost so far: €380 for all.
The only thing with Vokera, they did not take the old part!

I need to get my radiator circuit cleaned/flushed and inhibitor added. What price are we talking for this? It is a 3-bedroom house, with 10 radiators?

400-450.
Make sure a decent machine like fernox or kamco is used. Same goes for chemicals. Use only fernox, kamco, sentinel or adey.

Thierry

Dtp1979 wrote: »

400-450.
Make sure a decent machine like fernox or kamco is used. Same goes for chemicals. Use only fernox, kamco, sentinel or adey.

In average, what is the laps of time between power flushes should be carried out?
I don't want to spend money on a top of the range power flush, where a simple replacement of the water could suffice!

Can the color of water that comes out from a radiator air-vent give an idea of what is needed - from clear to deep-black, with the 50 shades of grey?

I presume if it comes out clear, nothing is needed, except addition of inhibitor in my case, as the leak from heat exchanger would have removed it.
And good news for this thread: no loss of pressure anymore overnight!


here are examples of different services offered. But which one to choose?
"
1. Deep Cleanse 6 to 8hr Hour Flush 500e
includes Fernox D 40 Full Pac Treatment & Ihibitor Protector

2. Recomended for Gun Barrel piping system 400e
Flush with medium sludge cleaner Magna Clean fitted for 6 hours to filter water on system full treatment & Inhibitor Protector.

3. Boiler & Radiator Flush 5 Radiators with mild cleaners & Inhibitor 375.00


4. FLUSH YOUR HEATING SYSTEM FOR 1 hour 168.00
Now 168e for the whole house !
INCLUDES Inhibtor Protector
cant get air out of radiators ?? we can ! tap in a new vent for you 40e
"

K.Flyer

Thierry wrote: »

In average, what is the laps of time between power flushes should be carried out?
I don't want to spend money on a top of the range power flush, where a simple replacement of the water could suffice!

Can the color of water that comes out from a radiator air-vent give an idea of what is needed - from clear to deep-black, with the 50 shades of grey?

I presume if it comes out clear, nothing is needed, except addition of inhibitor in my case, as the leak from heat exchanger would have removed it.
And good news for this thread: no loss of pressure anymore overnight!


here are examples of different services offered. But which one to choose?
"
1. Deep Cleanse 6 to 8hr Hour Flush 500e
includes Fernox D 40 Full Pac Treatment & Ihibitor Protector

2. Recomended for Gun Barrel piping system 400e
Flush with medium sludge cleaner Magna Clean fitted for 6 hours to filter water on system full treatment & Inhibitor Protector.

3. Boiler & Radiator Flush 5 Radiators with mild cleaners & Inhibitor 375.00


4. FLUSH YOUR HEATING SYSTEM FOR 1 hour 168.00
Now 168e for the whole house !
INCLUDES Inhibtor Protector
cant get air out of radiators ?? we can ! tap in a new vent for you 40e
"

If a system is power flushed properly, a mag filter fitted, inhibitor added and the heating system is in good condition overall, not needing to be repressurised on a regular basis, then you all you will ever need is the filter cleaned with the boiler service and a drop of inhibitor thrown into it.

As for the above list...

Completely disregard #3 and #4, waste of money.
#2 sounds like they put a filter on, but let the heating system pump do the work.
#1 sounds more like the right job, but as DTP says above, I would be asking more questions about the equipment and chemicals being used.

Dtp1979

2,3,4 Cowboys.
No.1 sounds like something off the menu at a beauticians.
DS40 isn't really for sludge. It's more for limescale.
Ask for fernox f5
Sentinel x800 or Adey Mc5
Also ask what machine is being used and if they use large magnets attached to the machine.
For inhibitors, only use
Fernox f1
Sentinel X100
Adey Mc1

Thierry

Most of the plumber I have talked to use "magnaclean chemicals..." no sure of the brand and their procedure is very unclear, type: I have to flush every radiator individually... I use magna.


Got only one company who uses Kamco machine and chemicals and they seem reasonably priced. The whole procedure will take 6-8 hours. So I am going ahead with them early next week.

Is a magna filter really needed?

Dtp1979

Thierry wrote: »

Most of the plumber I have talked to use "magnaclean chemicals..." no sure of the brand and their procedure is very unclear, type: I have to flush every radiator individually... I use magna.


Got only one company who uses Kamco machine and chemicals and they seem reasonably priced. The whole procedure will take 6-8 hours. So I am going ahead with them early next week.

Is a magna filter really needed?

If you mean the magna filter on the machine then absolutely yes. It makes the process much more effective.

Dtp1979

Thierry wrote: »

Most of the plumber I have talked to use "magnaclean chemicals..." no sure of the brand and their procedure is very unclear, type: I have to flush every radiator individually... I use magna.


Got only one company who uses Kamco machine and chemicals and they seem reasonably priced. The whole procedure will take 6-8 hours. So I am going ahead with them early next week.

Is a magna filter really needed?

If you mean the magna filter on the machine then absolutely yes. It makes the process much more effective.

daoirse

Hi folks,

I know this is an old thread, but since I stumbled across it and it's almost identical to my problem, I said I'd update it.

I have the exact same boiler (Vokera Mynute 25 HE) fitted almost the same time.
I have a very similar problem still waiting a final fix. The root cause seems to be water leaking somewhere in the boiler casing. Water is dripping down the left hand side of the condensing unit. I think from the above posts that it may be coming from the condensing tank and leaking down.
2 years ago, the same problem was happening and it had corroded the return thermistor that is attached to the copper pipe coming down from the Condenser. I was getting (I think an AL73 code).
Once the thermistor was replaced, the problem went away.
I've noticed that the water dripping only seems to happen at the coldest time of the year, and probably when I turn up the boiler temperature (Increased Temperature / pressure forcing the seals to weep?)
In my case, the water actually leaks down the pipe and sometimes pools at the base of the boiler.

One point, in case anyone's still reading is that there is a clear plastic "tank" that is L-shaped and goes to the left and above the condensing unit. It's not called out in the diagrams. In mine, this clear tank is yellowed and seems to have cracks in it. There is no obvious sign of water coming from the cracks, but it looks strange.


Colum