Worcester Bosch Greenstar 28CDi Compact - Problems?

[bigalxyz]

I posted about this a few weeks ago, but I have a bit more info to share now.

So...I had a new Worcester Bosch Greenstar 28CDi boiler fitted in my flat in January. Works ok, but two annoying problems:

1. Compared to my old boiler (Vaillant Turbomax Plus 828E), the sound of the water rushing through the radiators is very loud. Not gurgling, rattling, pinging type noises (which would suggest air trapped in the system), but just a "whoosh" sound like lots of water rushing through a pipe. I've bled the whole system but the whoosh is still there, so I don't think it's trapped air.

2. The pump speed often goes up and down (5 seconds up...5 seconds down...5 seconds up...5 seconds down...etc.), and this variation in the noise it makes is really annoying because the boiler is in the corner of my lounge. Also the whoosh sound of the water going through the radiators gets louder and quieter in sync with this.

Worcester Bosch sent an engineer round to check it over. He didn't seem all that interested, and basically said "that's just how they are mate, it's normal, nothing can be done". He mentioned the term "modulating pump". I asked him if there were any settings he could tweak to change the way it behaved, but he just shrugged his shoulders and said "nah, not really".

However...when I checked the installation guide for the boiler today, I saw some engineer settings seemingly related to this stuff on page 68 (screenshot attached below) from https://www.worcester-bosch.co.uk/p...r-cdi-compact-combi-installation-instructions

Do any of these settings give me a way to fix the problems I'm having? I don't know much about boilers, so I'd be wary of tweaking these settings myself, but if someone could tell me that I'm barking up the right tree, I would like to go back to WB and double check this with them.

Thank you.

 

[bigalxyz]

Anyone?!

 

[Jajodu]

You're on the right path, what settings are they on ATM? If it's on auto I'd change it to 2 or 3 and monitor it.

 

[bigalxyz]

You're on the right path, what settings are they on ATM? If it's on auto I'd change it to 2 or 3 and monitor it.

Thank you. Today I finally got around to tweaking the pump pressure map menu settings on the boiler. The options are:

0 - variable pump speed
1 - constant pressure (low)
2 - constant pressure (medium)
3 - constant pressure (high)
4 - constant pressure (max)

The setting was 4. I changed it to 0 (variable pump speed) and the annoying up-down-up-down noise seems to have disappeared (early days though).

I imagined that it had been set with the variable pump speed ie 0, but I was wrong. But perhaps constant pressure and constant pump speed aren't the same thing - is that correct?

Hoping what I've done isn't going to cause any problems...seems ok so far...would be grateful for any advice.