Myson Apollo 30/50 cutting out.

[Dan Robinson]

They are good LITTLE boilers when looked after. PITA when fitted at low level, but that is just me being tall and fat(ish)

 

[skodaman007]

yes dan,when i have been there it starts up quiet and runs quiet.

it has to last for another year,then i am selling this property. its on the fourth floor in a posh block and any external alteration like changing a flue needs to go through the freeholders which is like going to the dentist and having no pain reduction injections.

book your xmas parties now.

 

[claude2]

If it is a circulation problem, why does it cut out after 10 minutes?
Is there a simple way to test the pump? It does sound like it is running throughout.

 

[picasso]

These boilers have a pump overrun thermostat, when the boiler first starts up the gas valve is energised by the switched live, when the temp gets to around 60c the stat switches over to run the gas valve on a permanent live connection in the stat, it could be the contact of the permanent live is corroded and the pump is stopping when it switches over. View media item 51306

 

[claude2]

Is there a simple way to check this other than a visual?
If the overheat limit stat was faulty, could it cause this, or would it extinguish the pilot light?

 

[picasso]

If you think the pump is running all the time you need to check what voltage you have at the pump when the stat switches over, it could have gone high resistance and is dropping the voltage making the pump run slow.

 

[claude2]

I am getting 240v at the pump throughout, so it does nit sound like the pump over run stat.
Could it be a faulty overheat stat, or would this cut the pilot light?
Is there any way to test the pump, to see if it is failing?

 

[namsag]

Its not the pump over run stat as if this was faulty and cutting power to the pump it would sound like someone was hitting the boiler with a hammer as it is a low water content boiler and the heat would be trying to get away from it thus causing banging.

Its not your over heat stat as this would cause the pilot to drop out as you already think.

IS it cycling on both hi and lo settings .
Do the rads still get hot in the usual length of time

 

[claude2]

It is cycling on both the hi and lo settings, both on hw and ch.
All the rads just about heat up in the 10 mins or so the main burner fires for, but after that the boiler just cycles.

 

[steve32]

It's not a boiler fault it will be pump or blockage in heat exchanger or pipework.

 

[claude2]

Ok, how can I rule out a failing pump?
If there is an airlock in the boiler, how is this removed? It does sound at times like there is water slushing around in the boiler when the water is being heated, is this the symptom of an airlock?

 

[picasso]

Its not the pump over run stat as if this was faulty and cutting power to the pump it would sound like someone was hitting the boiler with a hammer as it is a low water content boiler and the heat would be trying to get away from it thus causing banging.

which is why I asked him to check what voltage he was getting once the stat changed over, low voltage would cause the pump to run slow.

Have you checked that there is water in the system ? blocked feed, expansion tank empty ect.

 

[steve32]

i would be looking for a blockage in pipework
take a magnet and see if you have a magnetic attraction on all the pipework around the area of the cold feed, vent and pump the stronger the magnetic attraction the more the pipes will be blocked
if there is an attraction then you will need to replace pipework on flow in area of cold feed/vent and system will need a good flush

hope this helps

Steve

 

[claude2]

Thanks for the advice, I will source a magnet to check.
Is there a simple way to check if the pump is failing?

 

[steve32]

Copied from faq (top of p & H forum)

20 ) CHECKING A PUMP using " The Finger Test "

Thanks to Agile

This is a simple way to find out if a pump is working properly using just your finger!

First remove the pump head but leave it wired up to the supply. It is important that an earth wire is connected to the pump and ideally it should be tested for continuity from pump body to earth.

The pump head is placed with the impeller upwards on a flat and firm surface. Hold the pump body firmly with the left hand and switch on the power. The impeller should spin! Use the right index finger ( 2 ) to press down on the left hand side of the impeller which should be moving away from the end of the finger.
By pressing down on the outside of the impeller it should be quite difficult to stop it moving. You will probably be able to stop the pump starting with the finger but again only by applying considerable pressure.

If the pump is spinning but can easily be stopped then its quite possible that the capacitor has lost some of its value and this can be measured to see how the value compares with the marked value which is often about 2.6 µF assuming that you have a multimeter with a capacitance range.

Read more: //www.diynot.com/forums/plumbing/boiler-central-heating-faqs.175736/page-2#ixzz29HN98Qjc