Loud banging noise from airing cupboard

[rec]

I am suffering from a loud banging noise that is coming from what I think is a pump in the airing cupboard - usually every time I use some hot water. It is loud enough to wake my family and me in the morning if we have had a bath/showeer the night before. The banging comes every few seconds, and seems to be from a small-ish white unit stamped with the name Drayton.

I have uploaded some pictures of the unit - here is a close up:

And here is a wider angle picture:

If I have my hand on the white unit, you can feel it shudder with each bang. The noise occurs every three or four seconds when (I think) the hot water tank is being heated. It is always preceeded by some quieter bangs. I first noticed this problem a few weeks ago and it is getting progressively worse.

Can anyone shed any light on what this unit is, and what the problem could be? Thanks very much in advance.

 

[Al-Glasgow]

I think the banging is coming from the pump, due to airlocks, or faulty pump.

The white box looks like a midposition valve and ive never heard these making loud noises.

have you bled the pump (the red thing) for air ?

Al

 

[rec]

have you bled the pump (the red thing) for air ?
Al

No - and I wouldn't know how! Is it a relatively starighforward exercise? I did wonder if it was some form of air-lock, as everything is actually working OK.

(thanks for the speedy reply BTW!).

 

[Al-Glasgow]

put the system OFF

there is a large slotted screw on the pump face (on the sticker side says GRUNDFOSS)

loosen this screw a little with a container below, hopefully u will hear a hissing sound, then water should flow.

Also there is a rising pipe close to the mid position valve (white box), look at the top of this pipe for a little bleed valve/screw, same procedure here, loosen and let out the air.

hope that helps

Al

 

[rec]

OK, I bled the pump, but didn't hear the telltale hiss of air escaping.

I'll see if I can find a valve on top of the rising pipe you mentioned (I believe this is the short length of pipe below and to the right of the pump, visible in the wider angle picture I posted) but a quick peek didn't turn up anything obvious - seems to be a simple cap on top of this pipe.

 

[rec]

One other slightly related question - when the system is on, and the pump is active, it gets quite hot - almost too hot to touch. Is this normal? Also, what setting do you recommend for the thermostat attached to the immersion heater?

 

[Al-Glasgow]

yes the pump gets hot.

your cylinder stat should keep water temps between 60-65 degrees C

So did you actually find any air when bleeding ?.

zoom in on that rising pipe, are you sure its just a blank cap ?

Al

 

[rec]

your cylinder stat should keep water temps between 60-65 degrees C

OK, mine is fine then.

So did you actually find any air when bleeding ?.

Not in the pump itself (well, no hiss when bleeding).

zoom in on that rising pipe, are you sure its just a blank cap ?

There doesn't seem to be a screw head on top - hard to tell in this image. I'll have to take a closer look in the morning.

 

[Al-Glasgow]

I didnt actually mean zoom in on that old photo lol

If you could get a close up picture, it might show a bleed screw.

 

[corgiman]

thats a thumb vent isnt it?

the brass nipple bit at the top should unscrew like a bottle top

sorry for butting in al

 

[Al-Glasgow]

sorry for butting in al

No worries there, I was hoping a regular would pass and suggest any ideas to help REC sort his problem.

Al

 

[chrishutt]

It looks to me as if the motorised valve might be fitted the wrong way around. I know it's a very old one, but all modern 3 port valves have the pumped flow entering in the perpendicular port and the two in-line ports are the alternative outlets. Can you check for arrows on the body of the 3 port valve?

Even if it's correctly orientated I would still suspect the 3 port valve as being the problem because it is very old and quite likely to fail. Does anyone recognise it? Is it a shoe or ball type?