Myson Apollo boiler noise

[mcaddy]

Sorry to cover old ground but...

My Boiler starts up then after a few minutes there is loads of noise in the pipes, kinda like valves or something clciking on and off(very loudly) then the boiler cuts out

I've bleeded all the rads, plenty of air!

Theres two black cylinders about 1 1/2" inches in diameter with a little red cap, what's this do i need to bleed her too, if so how?

The pump does start up the first time I turn the heating on and it makes a ticking sound which if I change the speed adjusts in regularity, when the boiler attempts to start agin I'm not entirly sure the pump is starting up!

I'm thinking my pump is probably on it's way out if not gone already, anyone else got an opinion?


TIA

 

[namsag]

The appollo also has a pump over run stat that gives power to the pump on start up, if this is faulty it will cause loud banging etc for first 45 secs untill temp is reached and power is given to pump

 

[kevplumb]

have you tryed opening the red caps on the black things (aav) and letting the air out ?

 

[mcaddy]

namsag> The banging doesn't start until about 2-3 minutes of running

kevplumb > I've openend the little red caps nothing noticable happend should i expect it to make a hissing noise or should i assume all ok as nothing happend?

I've now taken out my multimeter and measured the supply current from the boiler(I think) to the pump, all is fine(240v) until a couple of seconds before the banging begins it's at this point that the current drops back to 0v, I have a replacement pump but having seen that something is cutting power to the pump I'm led to belive that the pump is probablly ok, for the time at least(it's still quite noisy, the noise disapears once I open the drain plug)

Could there be something in the boilers controller that tells the pump to stop but continues to heat water?

TIA

All help greatfully recieved

P.S. how does an AAV work?

 

[namsag]

Yes .pump gets its power from the pump over run stat which is fitted within the boiler case. It is fitted bottom right hand side silver in colour about the size of a ten pence coin held on with 2 screws and 3 wires going to it. It will be sticking between contacts.This needs replacing ,same one is fitted to thorn appollo sorry don`t have a part number but only about £20

 

[kevplumb]

inside the black cylinder is a float and a valve air wont lift the float so air escapes
water lifts float and closes valve

are known for being blocked or stuck

 

[mcaddy]

namsag > My point was that the pump does get power on startup, your first coment said "if this is faulty it will cause loud banging etc for first 45 secs untill temp is reached and power is given to pump" this confused me as this is not my ptoblem the pump is powered up for the first couple of mintues, then it stops and be banging begins, could this also be a result of a faulty over run stat?

TIA


Mike

 

[mcaddy]

Fitted new pump problem still not sorted!!!

Everything is alot quiter running now so i guess that's a little progress!

 

[PEDANTICVINDICTIVEMAN]

Banging is normally down to lack of flow through boiler so pump normally fixes this sort of problem or pump over run stat, I would be looking for lack of circulation through boiler, blocked byepass or balancing valve, air lock? faulty auto air vent ? also would check gas rate in case govenor on gas meter has gone faulty and overgassing burner, if all ok would try Sentinel X200 and X100 to descale and inhibit.

 

[namsag]

Mcady my first comment should have said AFTER 45 secs or a bit longer. faulty pump over run stat can show up at various times of operation but initial start up is most common. Why change the pump, you said noise starts after pump stops getting voltage sent to it. So that means you change the part that supplys it voltage ie the pump over run stat. If the pump was still getting voltage and not working then it would have been time to change pump. The banging is caused by the heated water trying to get away from the boiler without the aid of the pump so if no power to the pump it clearly won`t be working.

 

[mcaddy]

fitted new overrun stat!

Still got the problem

only cost me £60 so far so I guess it's not cost too much, Yet!!

anything else I should check?

guess the next is a descale and inhibit?

namsag> The pump was noisy and was only running about half speed, so I figure it gonna need replacing soon anyway!

PEDANTICVINDICTIVEMAN > Don't think I have a byepass or balancing valve, arn't these only used in closed systems? there is no air in the radiators above the aav's and there seems to be an ok flow to and from the boiler, so even if the aav's are blocked this should be too much of a problem?

Transco have contacted me as they want to change my Meter, guess it might be something wrong with that? They say it's just old and due a replacement!

 

[PEDANTICVINDICTIVEMAN]

All the low water content boilers I know of need a byepass, sealed system or open vent, they can become blocked with sludge, I would be more suspicious of the pump being weak and be the main problem, if it's old do it anyway, the gas rate still needs checking, has anybody thats been done this ?
Sentinel X200 and X100, put them in together and leave, give it a fortnight to take full effect.

 

[mcaddy]

PEDANTICVINDICTIVEMAN > the pump is getting good voltage and is new, I don't think it's that, I'm going to get transco to change the meter soon!

Bearing in mind I can only run the system for about 2-3 minutes at a time is this gonna stop the X200 + X100 having any effect?

 

[namsag]

Is the voltage to the pump still going to zero just before noise starts.

 

[mcaddy]

namsag > seems to still be the same problem as before

I've taken the High and lo stats out and put them on my Hob, (probably not the best test) they both switch, the lo seems to switch off a fraction quicker that the hi (as expected), Safe to assume these are OK?