Gurgling/ Banging/ Whooshing noises from pipes.

[Daf]

Sorry it's a bit wordy, but I've provided quite a bit of info.

My system comprises of:

A Baxi Solo 2 80PF boiler with the thermostat set on 5 out of the possible 6
settings

14 radiators (3 small, 2 medium and 9 large) All bar one with TRVs

Danfoss SET 5 timeswitch

Grundfos Super Electric pump set on 3 out of the three speed settings
(numbers on it are: TF110, IP42, UPS 15-60 if that helps)

W-Pan or Y-Plan (don't know how you can tell which one it is) valve fitted about 6 inches from the pump. "Honeywell" seems to be the only marking on the aluminium coloured case.

Danfoss hot water tank thermostat set on 70 Degrees

Honeywell Room thermostat in the hallway


History:

Moved into the house in October last year. Before that, the house was empty for a year with the heating turned off and drained. Some of the TRVs had stuck and could not be freed up using pliers etc so I had a plumber replace all the TRVs and service the boiler. He checked out the system and everything seemed OK.

I regulary bleed the radiators but after about a week or so of replacing the valves I've never managed to draw off any air from any of the radiators. All radiators come on fine and TRVs seem to be working well. Furthermore, I cannot see any leaks in the system and all physically looks well.

The heating works fine in the morning as it is only on for about three hours. However, After it's been on in the evening for several hours, every now and again I hear a whooshing/ girgling/ banging noise coming from one of the pipes in the airing cupboard that leads up to the attic. This varies in volume up to the point when it seems as if every pipe in the airing cupboard is going to rip itself off the wall. Then everything settles back down again for say 20 minutes before the whole thins kicks off again.

I've taken a closer look and I have five pipes going from the airing cupboard up to the attic. One is the cold feed, two are warm to the touch and two are absolutely scalding hot. The two pies that are scalding hot come from a single pipe from downstairs. This single pipe also feeds into the pump. It's these scalding hot pipes which are making these fearsome noises.

Any ideas? I've tried running to the kitchen to see what noises the boiler makes and to be honest I reckon it must start there as I always catch the end of some banging before the noise propogates up the pipes into the airing cupboard and finally the attic. Is the boiler thermostat too high? Is it kettling (I think the term is called). Could there be a problem with the pump? What about the valve?

Thanks in advance.

 

[meldrew's_mate]

Are you sure you have TRVs on all the rads except one? The one in the room with the room thermostat must not have a TRV and must be turned on. If this is so check that the boiler turns off (on CH only) when the room 'stat is turned down. On the Solo the pump should be fed from the boiler and will run on for a couple of minutes after the burner shuts down.

It's possible you have an intermittant pump problem, but at this stage concentrate on the points above. An auto bypass valve may be of use later, it's not the solution now.

 

[chrishutt]

Could be a failed boiler thermostat. Can you check if the burner flames go out when you turn the stat down?

 

[Daf]

Are you sure you have TRVs on all the rads except one? The one in the room with the room thermostat must not have a TRV and must be turned on. If this is so check that the boiler turns off (on CH only) when the room 'stat is turned down. On the Solo the pump should be fed from the boiler and will run on for a couple of minutes after the burner shuts down.

It's possible you have an intermittant pump problem, but at this stage concentrate on the points above. An auto bypass valve may be of use later, it's not the solution now.

Somehow I missed out the fact that the plumber who came in to service the boler and fit the TRVs also fitted a room thermostat for me. However, the noises were happening before this change.

The radiator that is in the hallway (where the room thermostat is situated) has a TRV on it. I've turned this on flat out and everything OK for the moment. I tend to get the noise from about now onwards and if I do I'll post again tonight - hopefully.

 

[Daf]

Could be a failed boiler thermostat. Can you check if the burner flames go out when you turn the stat down?

Tried this by whacking the thermostat down to 5 degrees but the boiler continued to burn. I'm sure the plummer told me that the thermostat was controlling the valve near the pump and not the boiler. He said something like the boiler thermostat turns itself off when the water in the return pipe is hot enough?!!

As I said in the previous post all seems to be OK for the moment. All rooms are warm and no noise.

 

[chrishutt]

Tried this by whacking the thermostat down to 5 degrees

Less whacking and more reading please.....I said boiler thermostat, not the room stat.

 

[Daf]

Tried this by whacking the thermostat down to 5 degrees

Less whacking and more reading please.....I said boiler thermostat, not the room stat.

Fair enough. Tried this and yes the boiler does knock itself off when I turn it down. It then came back on when I turned it up.

Last night was fine and I thought we'd cured the problem by turning up the hall radiator to flat out. However, out of the blue tonight it started to bang and clang again. It sounded quite nasty.

 

[Al-Glasgow]

I have seen a similar problem.

I reckon bleeding the pump might help.

Al

 

[ChrisR]

Plain ordinary jellylike sludge can do it. Blast the mains through it!

 

[Daf]

Some major noises this evening. Sat down in front of the airing cupboard and listened to the whole thing develop. It starts off with a noise that sounds like small air bubbles coming up the pipe from downstairs that splits into three with one of them going into the pump. This noise builds up to a creshendo with massive banging and clanking. It then all dies down. The pump is running constantly throughout and is pumping water (probably air!) into the valve, which incidentaly is a Honeywell F5 Y-Plan and also noises propogate along the pipes that enter the attic . All is quiet again for around 15 minutes and the whole cycle starts again.

If it is air where other than from the radiators can I bleed it from?

If the pump needs bleeding (as suggested in a previous post), how do you do that?

If nether, are we talking about pressure washing each radiator and flushing out the crud? (System is no more than 9 years old but looks in excellent almost new condition)

Thanks in advance.