Boilermate II problem

[gwltabb]

Hi,

sat downstairs earlier only to hear a loud banging coming from the boiler cupboard - a familiar noise that we had about 18 months ago which we resolved.

The noise starts about 10 seconds after the boiler fires as soon as you turn the power on - its the noise of the water not being fed into the boilermate from the boiler, and being forced into the expansion tank at the top (I think!). Last time, the problem was the delay timer PCB not sending power to the primary pump, so replaced this and all was fine.

This time however, Ive done the electircal fault tracing and the PCB is fine, also, I'm 99% sure that the pump itself is running (put my hands around it and you can feel the vibration). If this is running, what else could be causing this? could it be a blockage or air in the pump?

You can hear what sounds like a bit of escaping air just before the noise starts, but I'm not sure if this indicates anything.

Thanks.

 

[cross thread]

have you checked you have water in the system ? ball valve jammed/blocked

 

[gwltabb]

I can check it - what would cause this to deplete? The heating has been on this evening and all radiators are warm, although I have noticed that the cylinder is cool, but I put this down to the heated water being in the raditators.

 

[gwltabb]

Header tank is fine. The more I think about this the more I think it must be the pump. Just need to wait until the pipes cool down to check whether the pipe gets hot upto the pump but not after it. Would the pump still vibrate even if it is stuck/clogged up?

 

[gas4you]

Banging noise whilst the boiler is firing, is often associated with a circulation problem, in this case the primary pump I would think.

Are you also not getting loads of hot water, ie enough to fill a complete bath?

If so this points to the primary pump as well.

 

[gwltabb]

It's only just started happening so theres still hot water, however the noise is too loud to leave the power on so the cylinder is going to start cooling down overnight.

My only confusion is that the pump is definitely vibrating, I'm not sure if this would be possible if it was clogged up, hoping it is and it just needs a clean!

I suppose the test is to see if the pipe get's hot upto the pump (to eliminate a problem with the boiler), and if it's cold after the pump it got to be pump issue?

 

[mickyg]

either the pump or the cold feed is blocked which is an absolute ball ache on these

 

[nickso]

cold feed is easy to get around. probably a couple of hours work for a novice.

either that or back fill it once a month.

 

[gwltabb]

All the radiators were hot just before it started and there is still some warm water this morning so I'm not sure it's the cold feed. What's the best way to check the pump is running? Am I right in thinking you can take the bleed screw out from the middle and you can see if the motor is turning?

If this is running, I guess it rill need taking off to see if it is blocked?

 

[kevplumb]

Am I right in thinking you can take the bleed screw out from the middle and you can see if the motor is turning?

yes have a cloth handy

 

[gwltabb]

When you're 99% sure, theres always the 1% chance you're wrong

So, replaced the pump and the banging has stopped and the everything seemed fine. This was until the temparature of the cylinder started getting upto temperature, and the new pump has started to make a hissing noise, which gets lounder as the temperature goes up.

I've tried turning the pump setting down to 2, the noise stops but the banging starts again, so the speed has to be on 3. What could be causing the hissing? It's exactly the same type of pump.

When the temperature of the water passing through it drops (i.e. when I turned the heating on), the hissing went away, but it came back after about 5 minutes. Water is fine and so is the heating - just the noise.

Any ideas?

 

[gwltabb]

Just to add to this, I actually think the noise is coming from the boiler, not the pump. Its almost like a sound of rushing water. Like I say it stops if you turn the pump down, but it starts kettling again.

 

[gwltabb]

One thing I did not do once I had installed the new pump was bleed it - could an airlock in the pump reduce the flow hence the noise and banging when reduced to speed 2? I can't bleed it right now as the pump is too hot but can't think what else it could be, I've only changed a pump?!

 

[nickso]

still could be a blocked cold feed, do you know how to back fill it? i would try it and see what happens.