Combi Boiler hot water problem.

[TCCHeating]

I fitted a new Worcester 38cdi Classic today.

It has a very wide plate HE but it looks like a big job to remove it with taking the boiler off the wall.

Come on someone, tell me how long it takes?

2 mins on the phone to wb. Boiler you fitted today is still under warranty.

 

[Greenie9657]

Well the gas man didn't show but he has assured me he's coming Monday. We'll see.

Anyway, checking the boiler yesterday the pressure in the central heating system has risen from the 1.5 bar that I set it to, to 2 bar. How can this internal pressure increase happen? I water refil tap is shut and pipe disconnected. And it never did it before the resetting problem.

Any ideas?

Regards

 

[Agile]

Some things start off small and then get big when they are excited !

Its called "expansion". It happens when you are feeling hot !

Tony

 

[Greenie9657]

Some things start off small and then get big when they are excited !

Its called "expansion". It happens when you are feeling hot !

Tony

Tony,

Completely happy with the expansion bit but not more than half a bar and continuing rising. I'm beginning to think I have a bigger problem. Let's hope I can nurse it through until tomorrow when te has man is here.

 

[Greenie9657]

It was 1.5 bar and over 2 days has risen by itself to over 2. That has never happened before.

 

[Dan Robinson]

Where is the filling loop?

 

[Greenie9657]

Underneath the boiler where the pipes go in. They are 100% shut off though. I've used them many times before. This problem has only come about since I cleaned the system. It's almost like its getting too hot and a thermal switch somewhere is shutting the boiler down.

 

[Dan Robinson]

Then you have a shot pate heat exchanger.

Glad is fit these shi|tboxes

 

[Greenie9657]

Dan,

Roger that mate. Are these things a DIY job to replace? I'm pretty competent with a spanner...... And hammer should I need it!

 

[snes]

If you have patience, a good supply of Anglo-Saxon, and the required O rings, then yes, you can diy it.

But as it will involve removing the room sealed case, the Gas Safe guys on here are not allowed to assist you.

Your boiler manual might be a good first port of call as it should do a walk through of most maintenance work.

 

[Agile]

Its the pressure when cold that is relevant.

If the device that absorbs expansion is not working then the pressure will rise to whatever it takes to open the pressure release valve.

EXVs on Worcesters seem to be a particular problem. I have a friend who has Worcs which is just two years old and she had British Gas cover. They don't seem very good at managing it and twice she has paid for me to come over and deal with it for her. At least I tell her when I am coming.

The correct advice is that a DIYer should never open the case of that kind of boiler as it forms the room seal which keeps it safe.

Tony

 

[Greenie9657]

Many thanks for all your help. I decided to go for it and have a look. I've been inside it before so just planned on having a look around. In the end I removed the plate and cleaned it out. There were loads of little black bits came out when flushed. I then opened something that looked like a filter, and it was. A magnetic one that was also clogged up and I also cleaned that and also some black bits out of the siphon. Not sure if any one of those things fixed it or a combination of the all but it seems to be running ok now. I wouldn't recommend doing it if you haven't delt with plumbing before but it seems relatively easy. Just a few unions, O rings replacement and job done.

 

[snes]

Well done that man!

Unofficially, of course.

 

[Greenie9657]

Of course!

Seriously though, if anyone reads this with the same problem, I would defo recommend to only attempt if brave enough. The plate was a right bar steward to get out!!

 

[Agile]

Welcome to the world of Worcester boilers!