New boiler - pressure dropping

[vtechnician]

Hi All,

Its been approximately 3 months since we had our new boiler installed. The job involved removing/disposing old conventional boiler from kitchen and installing a new (system) boiler in the attic. Furthermore we dumped the small HW cylinder for a larger one and a new Grunfos pump was added.

Quite annoyingly its been requiring a top up of water quite regularly - It drops 0.5bar in 3-4 days.

Before i go down the arduous route of calling the plumber who installed it (long story) i thought id do some preliminary checks myself.

Theres no obvious sign of a leak anywhere and Ive checked the PRV valve outlet which is dry. The ground floor pipework is encased in the concrete foundation so no joy here (I'll assume this is ok until Ive exhausted other possibilities). I have read that a leaky heat exchanger could be a possibility. The condensate pipe connects directly to the soil pipe. I was thinking of disconnecting it from the hose at the boiler end and checking for drips overnight with the boiler off. What do you think?

Any advice would be very greatly appreciated!

 

[Scott_D]

Any more info?
Boiler make/model
Pictures

 

[Scott_D]

Any more info?
Boiler make/model
Pictures

 

[newcastle phill]

When you go to bed...
Pressurise the boiler and make an accurate note of the pressure.

Then turn it off amd also islolate the flow and return valves on the underside.

This will seal off the boiler from the rest of the system.

If in the morning the pressure is exactly as it was the night before - the problem lays with your system somewhere and not the boiler.

If you do this make sure the boiler is off and set the pressure cold.

 

[townfanjon]

Was your original boiler / system open vented ?

 

[vtechnician]

Thank you all for your replies.

The old boiler was a conventional type and the new boiler is a Valiant 430 system boiler. We did away with the F&E tank but the cold water storage tank remains.

I couldn't find any valves to isolate the flow and return pipes near the boiler. This pipes run into the airing cupboard so I'll take a look there but i dont expect to find any.

Tonight, with a cold system and boiler off, i'll check for leaks through the condensate pipe and feedback my findings.

 

[Last Plumber]

A 430 is not a system boiler.

If it starts with 4 it's a regular boiler. Vaillant system Boilers start with a 6.

It may well be on a sealed system !

As per usual, I cannot open the photo's you posted. ( Forum Fault I think )

 

[Last Plumber]

Double post removed

 

[vtechnician]

Ive checked the invoice and it says ecotec 430 - i'll check the boiler when i get home.

So potentially he's installed a regular boiler and pressurized the system?? This sounds bad!

 

[vtechnician]

Ive checked the invoice and it says ecotec 430 - i'll check the boiler when i get home.

So potentially he's installed a regular boiler and pressurized the system?? This sounds bad!

ps right mouse click and open in new window/tab works with the photos.