Viessmann Pressure gaining

[Jim1000]

Hi, new to this forum.

Wondering if anyone can shed any light.

I have a Viessmann Vitodens 100-W WB1B 30kW Combi Boiler and it's been installed around 10 years so I know it's gradually on it's way out.

I have had no real issues apart from having to have a new pressure vessel fitted 3 years back.

Recently my boiler has started to increase pressure rapidly.

Sitting at 1.5 bar it now heads towards 3 bar within a matter of hours.

I release the pressure by draining water from a radiator.

I initially thought it was a filling loop problem so plumber has changed that and also fitted a new pressure vessel.

Next day pressure starts to increase again!

I have disconnected the filler loop to take that out of the equation and yet pressure still increases.

This is what I can't understand.

If it's a completely sealed system, how come when I turn the stop tap off the pressure remains the same?

Only other thing I could think of is the heat exchange pin-holing.

Asked my plumber and he said if its the heat exchanger than scrap it!

He didn't spot any water within the boiler, but again he wasn't looking for any so be interested to get someone else's opinion before I shell out for a new boiler?

If I need to, would you suggest sticking with Viessmann or jump ship and go down the Worcester route?

Many thanks.

 

[ShaunCorbs]

Easy way to test turn the mains water off to the boiler via the valve underneath

 

[Jim1000]

Easy way to test turn the mains water off to the boiler via the valve underneath

Many thanks for the info, I've just had a magnaclean professional 2 fitted so I have just turned the 2 valves off there and lets see what happens.

 

[ShaunCorbs]

Many thanks for the info, I've just had a magnaclean professional 2 fitted so I have just turned the 2 valves off there and lets see what happens.

That’s the heating not the water mains

 

[Jim1000]

That’s the heating not the water mains

Ok, I'm no plumber so don't know which valve I'm looking for, sorry.

Main stop tap shut off and pressure holds.

Interestingly having switched magnaclean valves off, pressure is stabilised.

Attached photo of pipework, hope that helps.

I appreciate your help.

 

[ShaunCorbs]

Do you see the middle yellow valve (don’t turn this off) the next pipe to the right this is the one

 

[Jim1000]

Do you see the middle yellow valve (don’t turn this off) the next pipe to the right this is the one

Do you see the middle yellow valve (don’t turn this off) the next pipe to the right this is the one

Removed the insulation from the tap, never seen this type of valve before, assumed this was a drain tap with only the hex bolt below

 

[ShaunCorbs]

Think of it like an iso valve so left to right off front and back on (the slot)

 

[Jim1000]

Think of it like an iso valve so left to right off front and back on (the slot)

Think of it like an iso valve so left to right off front and back on (the slot)

Unfortunately it's seized solid and I don't wanna force a valve on a Sunday Evening.

With keep taking water out from the rads to keep pressure down I'm I gonna run out of water?

 

[townfanjon]

when you sort the problem Jim theres plenty years left in that boiler

 

[Jim1000]

when you sort the problem Jim theres plenty years left in that boiler

Cheers, my plumber is scratching his head over this.

 

[ShaunCorbs]

Unfortunately it's seized solid and I don't wanna force a valve on a Sunday Evening.

With keep taking water out from the rads to keep pressure down I'm I gonna run out of water?

yea best no to get the plumber to fit a lever valve below the boiler on the cold mains

 

[townfanjon]

Cheers, my plumber is scratching his head over this.

Go with Shauns advice above first , its potentially a easy fix , we have to be careful giving out advice fixing boilers . Sorry.

 

[Jim1000]

Go with Shauns advice above first , its potentially a easy fix , we have to be careful giving out advice fixing boilers . Sorry.

Thanks for the advise, much appreciated.
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yea best no to get the plumber to fit a lever valve below the boiler on the cold mains

Thanks for that, looks like the valve has a brass land stopping you from initially turning it?

Will suggest plumber fits lever valve, but what would this prove?

As previously said, turning main stop valve off, pressure remains the same.

Having to keep draining water to keep pressure down, I'm I gonna run out of water in the system?

Any idea what it maybe as my plumber has no idea and suggests new boiler?

 

[ShaunCorbs]

if you done the mains stop tap test off for a good period then you have found its with the boiler

and tbh if your boiler engineer can find whats wrong with that info time to find another or you can call viessmann out for a fixed price repair around £300

 

[Jim1000]

if you done the mains stop tap test off for a good period then you have found its with the boiler

and tbh if your boiler engineer can find whats wrong with that info time to find another or you can call viessmann out for a fixed price repair around £300

Many thanks,

I have just got back from a 9 day holiday so turned mains stop tap off before leaving and left thermostat on low, on return pressure was exactly the same.

Turned mains back on and within hours, pressure was back at 3 bar and rising.

Will look into Viessmann repair as it's a lot cheaper initially than replacement.

One last question, as pressure keeps rising I'm taking water out of the rads twice a day, will I eventually drain the system as this concerns me?

Much appreciated with all your help.

 

[ShaunCorbs]

no wont drain the system as your putting water in always eg always filling

 

[Jim1000]

no wont drain the system as your putting water in always eg always filling

Ok so we're assuming that water is getting into the boiler even though it's a sealed system and filler loop was disconnected?

Will certainly check out Viessmann repair, worth a £300 punt to save on a new boiler.

Once again many thanks and have great evening.

 

[ShaunCorbs]

Ok so we're assuming that water is getting into the boiler even though it's a sealed system and filler loop was disconnected?

Will certainly check out Viessmann repair, worth a £300 punt to save on a new boiler.

Once again many thanks and have great evening.

it is as the pressure is rising with nothing running eg the boiler no heating

your more than welcome please do update us once you've either fixed or decided

 

[Jim1000]

it is as the pressure is rising with nothing running eg the boiler no heating

your more than welcome please do update us once you've either fixed or decided

No heating on and only using cold tap the pressure still rises.

Will certainly update you as things progress.

All the best.

 

[Drewy]

Cheers, my plumber is scratching his head over this.

I politely suggest you find another engineer. It’s an easy problem to diagnose and if properly looked after your boiler should be ok for many years yet. It’s better than a Worcester.

 

[king of pipes]

Easy repair for a GSI I very much doubt its the heat exchanger time for a fresh pair of eyes on the case . Kop

 

[Jim1000]

I politely suggest you find another engineer. It’s an easy problem to diagnose and if properly looked after your boiler should be ok for many years yet. It’s better than a Worcester.

Sounds like good advice, many thanks appreciate it.
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Easy repair for a GSI I very much doubt its the heat exchanger time for a fresh pair of eyes on the case . Kop

Many thanks, will call Viessmann UK tomorrow and ask for advice regarding getting one of their trained engineers out.

Certainly don't want to get a new boiler if my current one can be repaired.

 

[Jim1000]

Hi, just a quick update for you guys regarding my Viessmann pressure gaining issue.

Booked Plumber direct from Viessmann and he came down and sorted it within an hour!

Heater Plate Heat Exchanger 20 Plates 4 O-rings.

Pressure has remained stable ever since, all now ok!

Once again many thanks for all your info and help, much appreciated.

 

[townfanjon]

Hi, just a quick update for you guys regarding my Viessmann pressure gaining issue.

Booked Plumber direct from Viessmann and he came down and sorted it within an hour!

Heater Plate Heat Exchanger 20 Plates 4 O-rings.

Pressure has remained stable ever since, all now ok!

Once again many thanks for all your info and help, much appreciated.

Cheers for letting us know , first one pin-holed I have ever heard of .

 

[ShaunCorbs]

good thanks for the update case closed