Plumbers help - bubbling water cylinder

alant1000

Hi all

I've got a system boiler and over the past month or so my water cylinder is making a huge ongoing bubbling, gushing and dripping noise when the water is switched on. This happens when the water is not up to temperature and the boiler downstairs fires up. The noise (which is loud enough to wake us up) only stops when the system switches off after hitting temperature. I've so far had the following work done in the last 3 weeks with no difference -

1) full powerflush, including de gunk of expansion tank
2) new cylinder thermostat
3) new boiler thermostat
4) 3 port valve head replaced and body checked
5) new heating pump power head
6) system bled several times - still air coming out of the cylinder bleed valve.

This work (other than powerflush) was done via insurance, but as the water and heating work, my insurance company are no longer willing to resolve this (home emergency cover).

The noise was never there before, and no settings have been changed. The joins for the pipes and pumps are all tight, and this is a 30 year old house so not a new system or layout.

Air is getting into the system somewhere, but I'm stumped.

I have a newish shower pump and checked the connections there, all tight.

Does it sound like air is being sucked into the system? Anything I am missing at all?

Thanks

ValHaller

alant1000 wrote: »

6) system bled several times - still air coming out of the cylinder bleed valve.

You need to work out whether the system is not yet fully bled or whether it is drawing air somewhere

Myser

alant1000 wrote: »

I've so far had the following work done in the last 3 weeks with no difference -

1) full powerflush, including de gunk of expansion tank
2) new cylinder thermostat
3) new boiler thermostat
4) 3 port valve head replaced and body checked
5) new heating pump power head
6) system bled several times - still air coming out of the cylinder bleed valve.

This work (other than powerflush) was done via insurance, but as the water and heating work, my insurance company are no longer willing to resolve this (home emergency cover).

It seems that all they have done is just try replacing various parts without investigating where the noise is coming from or the cause. Which sub-contracting company did they use? You're lucky you didn't have to pay for all of that!

How long did the power flush take? Did they isolate all the radiators and flush each one individually? If done properly, it would take a full day in an average house.

southcoastrgi

What's the boiler make & model ?

ValHaller

I am waiting for the off on another plumbing derby.

Mr_Ted

Check the cylinder safety valve, possibly gunk disturbed and stuck under the seating?
If its this and it is a system boiler and unvented cylinder you should be losing pressure?
The noise is possibly coming from the tundish the safety expansion pipe discharges into, so check the discharge pipes for drips or water from them.

Could also still be air trapped in system?

keystone

Is it an unvented cylinder as Ted suggests or is it a conventional vented beastie?

Cheers

keystone

ValHaller wrote: »

I am waiting for the off on another plumbing derby.

Better get the popcorn then. I'm going to make a cuppa!

Cheers

southcoastrgi

The reason I asked for make & model as it's not clear if it was an internal expansion vessel or a f&e tank in the roof that was cleaned, if the latter then it's not a system boiler

Can I have salted popcorn please & no sugar in my tea, thanx

keystone

There you go. Mehera donated the mug. Think he likes you.

Cheers

mehera

All right boys - I have come to the rescue!!!

(Lol!)

I actually did have a job once that was very similair to this . . . .

They had air coming into the system - loads of unsucessful work done trying to solve the problem . . . .

In the end they converted the system over to a combi boiler set up due to the ongoing problem, hoping this would solve the problem!

In fact in the end we found out that the old system boiler had a vent pipe which was too close to the pump and it was sucking air into the system through this!

Still now they have their new set up they have not looked back and have no more grief from air in the system.

Why not get an engineer in to check the vent pipe (presuming there is one!) as this would be a prime suspect if you ask me!

By the way - I think we plumbers on here should get on with each other personally . . .

The problem with plumbers is that we are so damn opinionated!!!!!!

Still at least we know how to have a laugh huh?!?!