Oil Boiler-Working but still no heat in rads

airliebeach

Hello,
Hopefully someone can help with this.
I'm getting;
Good heat at Cylinder.
V little heat at Flow of 1st 2 rads.
Nothing in the rest of the rads.

Boiler is firing & heats up until reching thermostat cutoff.
Pump appears to be working (as in its making sound as if its working).
But hot water doesn't seem to be getting away from boiler.

Ideas?
I'm thinking either frozen return pipe OR faulty pump???

airliebeach

How can i identify a faulty pump??
its pretty loud (not just a hum) (brand = Salmson)

Wearb

airliebeach wrote: »

How can i identify a faulty pump??
its pretty loud (not just a hum) (brand = Salmson)

Usually very hot at boiler side of pump and a lot colder at the other side.



Where is pump in relation to the boiler?

A pic from a metre or 2 away might help. I'm trying to rule out air lock.

airliebeach

Wearb wrote: »

Usually very hot at boiler side of pump and a lot colder at the other side.



Where is pump in relation to the boiler?

A pic from a metre or 2 away might help. I'm trying to rule out air lock.

Its on the flow, about 10" of pipe away from boiler housing but physically sitting right up against the housing.
There is a fair heat after the pump aswell...
Also once it stops, stat cutoff, the expansion tank fills apparently, as it nearly drowned me as I stood looking at boiler.
So I think that indicates pump is ok (creating pressure)??

Sorry cant get pic as in work.

Wearb

An expansion tank doesnt wet you. Are you speaking about the pressure relief valve?

airliebeach

Wearb wrote: »

An expansion tank doesnt wet you. Are you speaking about the pressure relief valve?

Overflow from expansion tank..

Wearb

airliebeach wrote: »

Overflow from expansion tank..

I didn't realise you were talking of the feed and expansion tank. Some people refer to expansion vessel as expansion tank.
BTW that over flow should be situated in a way that doesn't present a scalding hazard.

Wearb

Very difficult to tell difference between faulty pump and air in top of boiler in a case like yours.

Best way is to eliminate the possibility of air first. Then if problem persists, change the pump.

whizbang

Sounds like it sucking air through the tank outlet..
What speed is pump set to ?

Have you an additional radiator thermostat, or room thermostat and/or valve on the radiator circuit?
If this is closed or stuck, thats all your symptoms right there.

airliebeach

Wearb wrote: »

I didn't realise you were talking of the feed and expansion tank. Some people refer to expansion vessel as expansion tank.
BTW that over flow should be situated in a way that doesn't present a scalding hazard.

Apologies, not overly familiar with the terminology

Wearb

airliebeach wrote: »

Apologies, not overly familiar with the terminology

Not at all. All the time here, people call the same thing by different names.

airliebeach

whizbang wrote: »

Sounds like it sucking air through the tank outlet..
What speed is pump set to ?

Have you an additional radiator thermostat, or room thermostat and/or valve on the radiator circuit?
If this is closed or stuck, thats all your symptoms right there.

Not sure what setting pump is at-its in a horrible position where setting cant be seen ir changed either.

There is a room thermostat!!
No other valves.
Is it possible this stat causes these symptoms?

whizbang

Watch the water level in tank when the pump switches on. It shouldnt change much.

It may be there is too much air in the radiators, and too little water in tank. Pump is sucking water in to replace air in rads, this pressure is then forcing water back into tank when pump is off.

airliebeach

Wearb wrote: »

Very difficult to tell difference between faulty pump and air in top of boiler in a case like yours.

Best way is to eliminate the possibility of air first. Then if problem persists, change the pump.

How do I get rid air from top boiler?
Sounds like strong possibility based on the sound from the pump.

Wearb

airliebeach wrote: »

How do I get rid air from top boiler?
Sounds like strong possibility based on the sound from the pump.

Different ways. A working automatic air valve. Opening the pressure relief valve (these often leak afterwards). Loosening a fitting. It can be difficult sometimes and patience and experience goes a long way.

airliebeach

Just some feedback.
Boiler man said pump faulty & replaced, all good now.
Thanks for all your help on here, much appreciated.