Central Heating wont fire

crasy dash

Howdy all hope someone can help.

My mam switched in on earlier today and about twenty min later realised no life in so called me to have a look at it.
Its a an old system its about 22 years old an old frebird and riello set up basic turn it on it comes on and works no stats zones etc.

Started with the obvious plenty of oil in tank electricity is fine etc.
Went to the boilerhouse and noticed it had started as it was warm but cut out for some reason

Removed the black cover to check hi stat but that is fine,isolated supply to the circuit
removed the grey cover of the dual thermostat housing continuity is fine on the high stat cut out side but open on the temp side adjusted it up and down still the same.
Left it to cool down incase it was warm but still the contacts wont reset ,removed the reataining screws and put the stat in cold water and it closed, problem is when i put it back in within a minute or two it opens again.

Would a faulty circulating pump hold the stat out by any chance? The only reason i think this could have happened as the esb did drop ina nd out a fews times yesterday while the heating had been switched on, I powered the pump on and held a screwdriver to the body i can hear it noising but one side of the pump is warm and the other is cool

Any advice before the the plumber calls in the morning.
Not looking to fix just a rough idea so they half know what he might say in the morning

Thanks in advance lads

listermint

can you hear the pump working? any vibrations out of it, put screwdriver on it.

If stat is faulty then could do what its doing.

if pump is faulty then stat is doing its job, no pumping beans the water would heat up quite quickly close to the boiler.

crasy dash

listermint wrote: »

can you hear the pump working? any vibrations out of it, put screwdriver on it.

If stat is faulty then could do what its doing.

if pump is faulty then stat is doing its job, no pumping beans the water would heat up quite quickly close to the boiler.

Thanks for the reply

I can hear a hum when I put a screwdriver to it but what's throwing me is the pipe is warm one side of the pump and not the other.

I think the stat is good as it cuts out and resets when put it water .

A bad pump has me thinking the water isn't being circultaed and that's the reason the stat operates so quickly.

The pump is wired in flex with tiny connections so I can't get my amp clamp on it to test if the pump is actually doing anything.

listermint

If its super hot on the input and not on the output then suggest pump is busted. clogged or just gone. Motor may be spinning but impeller could be not moving.

Sounds very replacementy tbh.

Wearb

Is there an open automatic air vent on top of your boiler?

Where is the circulating pump in relation to the boiler?

crasy dash

Wearb wrote: »

Is there an open automatic air vent on top of your boiler?

Where is the circulating pump in relation to the boiler?

Not too sure what that looks like to be honest,pump is literally within a foot of the boiler.

I just managed to get an amp reading from the phase going to the pump its pulling 0.55a when its rated for 0.38a so maybe its jammed and not circulating.

Hopefully the plumber arrives in the morning and i can update on if he gets it sorted

Many thanks for the replies and guidance:)

Wearb

crasy dash wrote: »

Not too sure what that looks like to be honest,pump is literally within a foot of the boiler.

I just managed to get an amp reading from the phase going to the pump its pulling 0.55a when its rated for 0.38a so maybe its jammed and not circulating.9

Hopefully the plumber arrives in the morning and i can update on if he gets it sorted

Many thanks for the replies and guidance:)

Just a well to wait for plumber then.

You could try dipping the thermostat phial into a flask of 70c ish water and see if the stat clicks on and off as you turn it up and down.

Most likely the pump anyway.

crasy dash

Quick update plumber called this morning and diagnoseda faulty pump.

Replaced back up and running many thanks for the helpful advice.