Noisy central heating in the summer...?

[19ninety]

Hi,
I have the most annoying noises coming from my heating system. I'll put as much info below as possible, I hope someone can guide me in the direction of a solution

I have a Potterton Prima 30F combi boiler on an open vented system. Here is what's happening... when the programmer comes on the pump starts and the boiler fires up, theres a lot of bubbles heading up from the boiler which make a load of noise as the hit the pump. From then as long as the pump is running regardless of if the boiler is alight, there is a watery noise from the pipes at the boiler and occasional glugging and the noise at the pump of the air going through it.

I've tried a few things to fix this, with my limited knowledge (and the internet), first was to turn the central heating on and bleed the radiators, a little air came out but nothing spectacular. Second was to bleed the valve at the high point in the airing cupboard, no air, just hot water. Third it was suggested to try adding Sentinal X200 noise reducer to the system (through rad in bathroom, have run up the C/H a couple of times to circulate fully), the aim to make sure there was no scaling in the boiler. However the problem persists

Now interestingly, that was a year ago ... I gave up a put up with the noise as there were more important things to do. However its started again now that it's really warm outside. Could this be over heating of the water?? Or coincidence that I've noticed it again a year on? Seems a bit odd!

I've added some pics, and a couple of videos to try and help... whats the next thing to try? Its driving me nuts!

Noise at pump:

Noise at boiler:

Noise with boiler fired:

https://youtu.be/OtUNKg-u5eA

 

[JohnD]

It's not a combi.

If you sit next to the small loft tank when the boiler is turned on and off and on, what happens? How deep is the water in it, and what happens when you press down the orange float?

When you bleed the highest radiator in the house, does water squirt out forcefully?

 

[MrTherm]

Some further checks to make...

There is a bypass branch between the pump and 3 port valve, locate a valve on this pipe and check if it is open or closed.

This valve must be set for a minimum water flow of 9 litres/min through the boiler ideally via 4 metres of 22mm pipe between flow and return boiler connections.

This bypass valve setting can greatly affect the water flow noise level especially if set too far open.

Check also that the pump is wired directly to the boiler terminal block.

 

[dilalio]

Another component to check is the 3port valve to make sure it is functioning properly - could be that flow to CH is not being shut off fully when there is no demand for it!

 

[baldykev]

looking at the F and E tank water looks very dirty/brownish colour and looks low to me .

 

[baldykev]

sorry had another look ,looks like loads of sediment in tank.Is there ?

 

[Stadan20]

Pump speed is abit low also

 

[19ninety]

Cheers for the replies folks, sorry for not replying sooner, been mega busy (partly why I didnt bother looking in to this again over the winter since it had also quietened down).

Tired setting the boiler to #2 on the dial instead of 3, no change. Just sat here now and no TV on so quiet in the house and its on the last cycle tonight making the damn noise, 22:30 and the programmer turns off and the noise stops. Temp on hot water tank is set to 55C btw.

I'll quickly reply to what I can now and add replies to the more involved questions tomorrow.

It's not a combi. Sorry - I thought it was as it heats the CH and HW?

If you sit next to the small loft tank when the boiler is turned on and off and on, what happens? How deep is the water in it, Will check tomorrow. and what happens when you press down the orange float? Water comes out the valve outlet as it should, stops when the float is released.

When you bleed the highest radiator in the house, does water squirt out forcefully? Yes.

Some further checks to make...

There is a bypass branch between the pump and 3 port valve, locate a valve on this pipe and check if it is open or closed.

This valve must be set for a minimum water flow of 9 litres/min through the boiler ideally via 4 metres of 22mm pipe between flow and return boiler connections.

This bypass valve setting can greatly affect the water flow noise level especially if set too far open. Will have to look at these points tomorrow.

Check also that the pump is wired directly to the boiler terminal block. Pump, 3-way valve and hot water tank thermostat all go to the junction box on the wall, terminal block inside.

sorry had another look ,looks like loads of sediment in tank.Is there ? Water is clean but yes there is some sediment in the tank.

Pump speed is abit low also. Have set to 2 now to see if it makes any difference, I had set it to 1 as it's only a 2 up 2 down semi, 7 radiators total, place is plenty toasty in the winter even with the boiler set to just 3.

 

[dilalio]

For this to occur at the time of year when demand for central heating lessens, I would start with the 3 port valve. Isolate the electrics, remove the head and manually manipulate the valve pin (it has very little oscillation but should be easily moveable by forefinger and thumb), lubricate as necessary. Then move on to the (actuator) electrical head and check that is operating as designed - you can google how to prove this, if not - replace the head.
Check this first to eliminate it from further enquires - as they say on crime watch