Valiant Boiler issue.

delmel · 21 Oct 2021

Hello I have a Valiant (not a combi boiler) I think its an Ecomax pro 18 or 28. The boiler has not been massively used due to house not being occupied, it was last started and run about three years ago maybe even longer. I have fired it up today and it is not functioning correctly. It fires up and starts but after about 20 seconds it makes a weird noise like a grating or air lock and shuts off. The pipework flow and return gets hot but does not reach the pump sited very close, before it shuts down. The external pressure gauge at between 1 and 1.5 bar on the relief valve, also jumps like mad prior to the noise and shut down, it may also now be releasing water.

Any ideas or expectations of the issue ? I am going to check to see if the external Grunfoss pump is turning as this I am thinking may cause the problem if it has failed.

denso13 · 21 Oct 2021

delmel said:
I am going to check to see if the external Grunfoss pump is turning

Yep, try this, it may have seized by sitting for so long.

Harry Bloomfield · 21 Oct 2021

denso13 said:
Yep, try this, it may have seized by sitting for so long.

Unscrew the large headed chrome screw, which covers the end of the pump shaft, insert a large flat screwdriver and see if you can turn the shaft round. It may have seized from lack of use. Shaft end, should be spinning, when boiler is running. Expect a small amount of leakage when chrome screw is removed.

delmel · 21 Oct 2021

Harry Bloomfield said:
Unscrew the large headed chrome screw, which covers the end of the pump shaft, insert a large flat screwdriver and see if you can turn the shaft round. It may have seized from lack of use. Shaft end, should be spinning, when boiler is running. Expect a small amount of leakage when chrome screw is removed.

I did take that out yesterday, but never had a driver on me to check that way. It did however have a spurt of water which seemed continuous and very warm even though the boiler only fired for that very short time, which seemed odd.

Harry Bloomfield · 21 Oct 2021

delmel said:
I did take that out yesterday, but never had a driver on me to check that way. It did however have a spurt of water which seemed continuous and very warm even though the boiler only fired for that very short time, which seemed odd.

Nothing odd about it. As I said, pump running or not - you can expect a trickle of water once that chrome plug is removed. You need to use a screwdriver to turn the pump, to ensure it is free and not seized. Then perhaps to ensure it runs when powered, by listening to it or even better by poking a driver of some sort on the end of the shaft.

delmel · 21 Oct 2021

Harry Bloomfield said:
Nothing odd about it. As I said, pump running or not - you can expect a trickle of water once that chrome plug is removed. You need to use a screwdriver to turn the pump, to ensure it is free and not seized. Then perhaps to ensure it runs when powered, by listening to it or even better by poking a driver of some sort on the end of the shaft.

Well open it and I could not see any slot inside on the shaft. My eyes are not the best but I had glasses and a torch. Have they changed them to no longer have a slot but two tiny slots. It certainly never felt like it would move / rotate.

Harry Bloomfield · 21 Oct 2021

They have not changed, that I am aware. It should be a nice wide slot in the dhaft end, so you can fit a large flat screwdriver in. You will need to see if it can be turned.

delmel · 28 Oct 2021

Update
It was the external Grundfos pump ceased up, also now need to replace the pressure release valve as leaks now it was activated.

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Valiant Boiler issue.

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