Pressure Vessel Location and Testing

[Chris_J]

Hello all.

I'm having problems with my Icon 23T boiler (I know, I know) which of course is nicely timed for the cold weather.

Basically, the boiler is losing pressure quite quickly as it is passing through the pressure release valve. I want to determine whether the problem lies with the PRV itself, or with the pressure vessel, before I get someone in to do the work. From reading around, the best way for me to do this is to test the PV and see if it contains any water. That way I'll know if the PV is in good shape.

I feel I'm reasonably familiar with boilers enough to do this myself. However, for the life of me I cannot find the location of the PV or access to a schrader valve for testing. I have found the PRV / Autovent which looks like the image below:

A red pipe is connected to this which leads outside, where the water is leaking from.

An external PV is not fitted, so the only other place it could be hiding is in the main silver galvanised compartment of the boiler, but from what I understand, this is the combustion chamber and contains only the main burner assembly.

Any ideas?

 

[Bahco]

Are you sure the filling loop is not switched on. Look in the faqs for how to check the PV.

 

[Chris_J]

I've had a look in the FAQs for testing the PV, but it requires you to actually find the PV and gain access to the valve!

If the filling loop was switched on, would that not just overpressurise the system?

Cheers.

 

[Steve69the69Gas]

Yes and dump water outside thru the PRV pipe - you call it a red pipe

 

[Chris_J]

Ah, I see.

But, the system pressure is normal. When in use, the PRV pipe drips at a reasonable rate to the outside. In the morning, the pressure reads about 0.6bar. I top it back up to 1bar and the cycle starts all over again.

I have just assumed this is either a PRV or PV failure. I hadn't thought about the filling loop, so thanks for the advice.

 

[Steve69the69Gas]

To repeatedly intoduce fresh water into the system will lead to corrosion of the rads etc - rapidly.
It seems the PRV needs replacing as it is not seating correctly (closing) which is quite common.
When replaced by whoever- get it dosed up with inhibitor.

 

[Chris_J]

Yeah will do. I have a bottle of X100 ready for when it's sorted.

 

[collyplumb]

Hi,
I have checked boiler manual and it says the expansion vessel sits behind the heat-exchanger. The only way I can see access if from the top of the boiler looking down behind the boiler. The worcester boschs have access from the top but I have not seen the Icon "live".

 

[Chris_J]

Hmmm. The boiler is mounted hard up against the wall, so it sounds like I'll not be able to get to it. Certainly not from the back anyhow

 

[collyplumb]

Is there any space to get your head over the top and look down the back of the heat exchanger?

 

[Chris_J]

There is plenty of room above the boiler. I had the torch out last night trying to find the PV valve, as I had heard some boilers provided access from the top.

There is no sign of anything there, unless I have to take the silver cover off, but then I'm exposing the combustion chamber..?

 

[collyplumb]

I can send you the manual. How do I get your email address? without us all receiving stuff from all over the web! if there is a metal strip covering only the rear 1/3 of the top of the boiler then this can be removed without exposing the HE.

 

[Chris_J]

That would be great. I think I can send you a PM with my address. I'll give it a go...

 

[Chris_J]

Apparently, you have to accept me as a friend in order for me to send a PM to you. I've sent a friend request