Worcester Bosch Combi Boiler

[chrispriddyuk]

Hi there.

I replaced a rad in the bathroom for a towel rad.
Having done this I used the filling loop under the boiler to bring the pressure gauge back up to 1 bar.
I then thought I would bleed all the rads in the house as this prob hadnt been done in a while and having completed this the pressure gauge showed 4 bar.

There is a little pipe that comes out the bottom of the boiler, and goes through the wall.
This has been dripping water ever since but the pressure has not gone down in almost a week. The boiler seems to be working as it did but I just cant work out how to reduce the pressure.

Any help?
Thanks

chris

 

[mikej2005]

Bleeding air from the radiators should usually cause the system pressure to drop, not increase. Are you sure you've turned off the filling loop properly ?

Make sure you do all the pressure testing when the system is cool/cold and aim for around 1 bar when cold. This allows for the extra pressure generated when the system heats up.

The 'little pipe' you refer to is probably the drain for the pressure relief valve, which normally kicks in around 3 bar.

Don't be tempted to play with the pressure relief valve to relieve excess pressure manually, as this can introduce debris into the valve and cause it to require cleaning or replacing. Instead, try and find a suitable drain-point - you often get one on one of the boiler flow or return elboes or at the lowest point in the system (a downstairs radiator, or beneath the boiler if your pipes go downwards).

 

[chrispriddyuk]

OK, so check the filling loop is fully off, then drain water from the system until the pressure reduces.
Do all this when system is off and cold.
OK
Will give it a go, thanks

Chris

PS is the high pressure doing any damage?

 

[mikej2005]

PS is the high pressure doing any damage?

Not sure, but if it's around 4 bar when cold, then that'll be outside the normal operating temperature of the boiler I would suspect.

Personally, I would relieve the excess pressure before using the boiler again.

Do you have the built-in plastic filling loop (with key) as found on the underside of some WB boilers, or a separate, braided flexible loop on the pipework below ?

Check out the FAQ section above for info about the former and for other tips which will be useful.

 

[chrispriddyuk]

Hi
Its a flexible metal pipe filling loop
AND correct answer is that it wasnt fully off, seems i over turned it and it must have been on a slight open ever since thus keeping the pressure at 4 bar.
I have corrected this and its dropped to 2 bar. Just waiting to see if it will naturally drop any further. If not i will remove some water using the valve on the flow pipe just below the boiler.
Seems we are on the way to recovery.
Thanks

Another quirk it has had recently that i need seeing to properly i think is:
If heating is off and you turn on the hot water tap it will run for 90 secs then make a banging and hissing noise and stop producing hot water. You then have to press the reset button to get it to work again. HOWEVER if the heating is on hot water works fine for about 4 - 5 mins before going luke warm and then back up to temp again and repeating this ever 4-5 mins.
Any ideas on that one??? It recently had a new pump and a few new internal valves for things

Thanks again
chris

 

[mikej2005]

Glad to hear you've sussed it. Try and aim for around 1 bar if you can, although the exact figure isn't too crucial, provided it's above the minimum operating pressure (my WB combi's is 0.75bar - check your manual).

When you've got it to a suitable level, check that it doesn't get too close to 3 bar whilst in operation.

I can't help with your other problem I'm afraid, although I'm sure someone else will be able to.