Worcester 28i RSF Problem

[richyje]

Hi,

I have recently had an extension built and have had the boiler moved from an upstairs cupboard to the downstairs utility room.

We had new Radiators installed (8 in total) and completely new copper for the whole system. The whole system is new apart from the boiler.

All the Rads are getting hot, but the boiler's pressure gauge is fluctuating and a horrible knocking noise is heard when the central heating is on. This noise nor the pressure gauge fluctuates when there is a hot water demand.

I initially thought the issue could have been something stuck in the Central Heating circuit (ie the pipes near the pump), so they have been disassembled, cleaned and put back together. I accidentally snapped the impeller off the pump when removing it, so have replaced this with a new pump.

Today, I have Power Flushed the Boiler with FX2 and removed a load of black ****e water, but the issue remains.

Any idea's what could be causing this knocking ?

I have a small video on you tube of the boiler and the knocking noise...
http://www.youtube.com/watch?v=sDTY-2kUchc

Thanks,

Richard

 

[bigpkr]

Vid doesnt work for me?

Sound like from what you say it is having a problem getting rid of the heat when its running the heating, so flow filter could be one to check so to if there is dirt in there.

 

[richyje]

Just uploading the video now, it is 90% done, so should be available in a few mins

 

[richyje]

I cannot see a flow filter on the boiler.... I have looked in the boiler installation and servicing instructions and cannot see anything about a flow filter. Do you know if a 28i definately have one ?

Thanks,

Richard

 

[bigpkr]

What the gc number for the boiler?

Sometimes the fitler just sits on the return valve and doesnt have a part number as its part of the valve.

 

[richyje]

GC Number is : G20 47 311 54

Thanks

 

[richyje]

Would there be a filter in the flow or return isolators... ie when my 22mm copper flow and returns connect to the boiler ?

as shown in the following video...

http://www.youtube.com/watch?v=QWdjoyuwYWk

 

[Maxsys]

If its anything like my 28CDI then probably air in the system causing the noises, you would be suprised how much noise this can make, mine is an absolute bar steward if completely drained down, have you bled the pump?

 

[richyje]

yes, I have loosened the screw cap off the pump and some water has expelled.

 

[richyje]

Could I have too many Radiators on the Central Heating Circuit and the Expansion Vessel cannot cope with the expansion ?

I have 11 Radiators in Total...

3 * 1200 * 600 Double Convector
4 * 1000 * 600 Double Convector
2 * 400 * 600 Double Convector
2 * 500 * 1200 Towel Radiator

 

[Maxsys]

It's not water your after, it's air, last time i did mine when i replaced the heat exchanger, it was so bad i drained down and refilled and bled again, only way i could get the air out, might be me but i have read that the 28CDI can be a swine to get the air out off, i don't know if yours is the same.

Highest point in my house is a towel rad in the loft and even after two weeks i still got a bit of air out, once cleared it was fine, noise was really bad though before i drained down and refilled, the boiler even cut out a couple of times, i am no expert just passing on my experience of a similar problem.

 

[richyje]

Thanks for your help.

Have you seen the video I posted above ? did yours sound like that before you expelled all the air ?

Richard

 

[bigpkr]

If the expansion tank cant cope with the expansion the pressure will rise above 3 bar, safety valve will open, extra water will come out of prv, system will cool down then have no pressure left in it.

Filter could be in return valve as i said.

Air in boiler would cause the same fault as air really has no where to go when in dhw mode.

 

[Maxsys]

Thanks for your help.

Have you seen the video I posted above ? did yours sound like that before you expelled all the air ?

Richard

Yes almost exactly the same, and the same needle bouncing around as well, what speed setting is the pump on? If it's a three speed pump try turning it down to 1 or 2 and whilst running open the bleed screw on the pump a few times.

Like i said i drained mine down and started again.