Airlock?

[dazzarosh]

Hi there,
I got called out to a system boiler, it will fire up for say 30 seconds then cuts out. The boiler makes all sorts of noises. I have checked the flow to the cylinder which gets hot, but the return is cold plus cylinder. No fault codes on the boiler. It only has one large header tank. Is it a primatic cylinder and if si is the dome knackered. These syptoms happen on dhw and ch.
Help would be appreciated.
cheers

 

[bengasman]

Bit uncommon for a systemboiler to have an airlock that bad.

 

[namsag]

A system boiler would not have a header tank so it wont be primatic

 

[dreadnoughtheating]

A little bit 'off-topic', went to a 'House in Multiple occupation'. Symptom was No Hot Water, water to tap, but not hot.....

Pulled down facia on boiler (Vaillant 415 open vent), one year old, F.22 code showing (dry fire). hmmmm

Looked in cyl cup'd, and sure enuff, plenty of water at AutoAirVent. had another look at pipework, and sure enuff a tenant had fully closed the valve restricting the cylinder return.

Why?, the (electric) shower was not getting hot enough so he thought he would have a fiddle....

opened valve, reset boiler, happy days.

SO, to summarise, check all pipework and valves are doing what they should.

 

[dazzarosh]

Thanks for the replys, but does anyone have any idea what this could be, or the best way to approach this? I have checked all valves, all open. I cannot get to pump or port valves as under laminate, but the hot water mode stll goes to cylinder and stops point blank at cylinder inlet.
Many thanks

 

[Goldspoon]

You might have an airlock

Have you tried turning the pump up to max to try and push any airlock out?

Have you bled the pump?

You could attach a hose to the drain plug of a lower floor rad and drain off for a good while - can send air out the hose...

Failing that send water into same drain point via a hose (mains pressure) and push water into F&E tank.

 

[dazzarosh]

Thanks for that , will try. As for the pump i cannot physically find it and diverter valves. I presume there under the bedroom floor which is laminate(great place for laminate) as this is only the direction of the pipes.

cheers all

 

[Fluffster]

Could be a blocked heat exchanger full of crud.

Pete

 

[PRS1]

could u fill system through exp pipe

 

[mickyg]

how bout check the system pressure?????????????

when you say "called out" in what capacity? are you a heating engineer???

 

[dazzarosh]

Hi,
Yes i am an engineer but fairly new (2 years) to this trade, but just never came across ths b4.Pressure seems ok on water side.Emersion works fine and pressure. PRS1 what do you mean by exp pipe
cheers

 

[mickyg]

you've never come across a system boiler? assuming you've correctly identified it as such? What boiler is it?

 

[dazzarosh]

Hi , yes i have came across system boilers b4 but not with this problem. It is an ideal boiler
cheers

 

[Legion]

I got called out to a system boiler, it will fire up for say 30 seconds then cuts out. The boiler makes all sorts of noises. I have checked the flow to the cylinder which gets hot, but the return is cold plus cylinder. No fault codes on the boiler. It only has one large header tank. Is it a primatic cylinder and if si is the dome knackered

.


Glad you were never called out to mine, Clueless? why did anyone call you? Check pump.

 

[dazzarosh]

Glad i wasn't called out to yours, if you have nothing better to say. Everyone has to start somewhere.I cannot get to pump as under the floor which is laminated.