Smell and gurgling of central heating water

[leegsi]

Had a loft conversion done a few months ago which added an extra radiator in the bedroom and towel rail in the bathroom and everything was fine.

The radiator in the bedroom now gurgles when it comes on (Tried bleeding it and water comes straight out) but I can bleed the towel radiator.

The towel radiator can be bleed every few weeks and air does come out but it smells where as before the work it didn't on any other radiator in the house.


Also the last few weeks when running a bath or shower the water temperature fluctuates alot from being normal temperature to nearly cold enough to not be able to stand under it

 

[oldbutnotdead]

What sort of system- pressurised or open vent? And hot water- combi or cylinder (vented or unvented). What's the towel rail made of? Have you tried lighting the gas coming out of the bleed valve?

 

[leegsi]

Combi boiler.

Not tried lighting it.

Towel rail is chrome

 

[oldbutnotdead]

Hokay. Do you know what's under the chrome (is it copper or Something Else- I'm wondering galvanic corrosion here). Did you or whoever top up the system with inhibitor when it was drained/refilled to add the rads?
And not a combi expert but I'm wondering whether a load of crud has dropped into the diverter valve when you drained the system. Have you tried getting someone to run the bath while you're at the boiler watching what its doing (in terms of flame mostly)

 

[bernardgreen]

Have you tried lighting the gas coming out of the bleed valve?

Please do NOT try lighting the gas as it comes out of the radiator. There is a risk that it is an explosive mixture of Hydrogen and Oxygen.

The mixed gases will be able to burn back through the bleed valve and detonate the mixture inside the radiator.

If it is only Hydrogen then it will not burn back through the bleed valve as there is no Oxygen in the bleed valve to support combustion.

 

[Madrab]

Do you have to top up the boiler pressure regularly? What sizer is the pipework? How old is the boiler? Smell may be inhibitor. Have you had the installers back in to check?

 

[leegsi]

Boiler stays lit but the taps go hot and warm (Not cold).

They are builders that fitted it (Multi trade) and not boiler specific so suggested getting a plumber in who deals with boilers (It was working fine for a few months after.

Dont have to top up pressure unless I bleed it.

Boiler is about 10 years old and new pipework is 10mm (I think) speed fit.


Could it be a partly blocked plate heat exchanger?

 

[Madrab]

Don't have to top up pressure unless I bleed it.

OK so it may not have a leak and it could be hydrogen - a by product of certain types of corrosion - this would need to be checked for.

Hot and cold symptoms could be a restricted Plate HEX, when the shower is on does the boiler get up to temp then cycles on and off?

 

[dilalio]

Boiler stays lit but the taps go hot and warm (Not cold).

They are builders that fitted it (Multi trade) and not boiler specific so suggested getting a plumber in who deals with boilers (It was working fine for a few months after.

Dont have to top up pressure unless I bleed it.

Boiler is about 10 years old and new pipework is 10mm (I think) speed fit.


Could it be a partly blocked plate heat exchanger?

IMO you'd be better off getting an engineer in. Builder's often leave issues with a system when they tinker with plumbing (which they usually do to A) Save money and B) can't get an engineer on demand).
This way, you can get the system appraised by an experience eye, get any defects highlighted and have the boiler serviced, even if it isn't due, which is good practice after building works.

 

[leegsi]

Hot and cold symptoms could be a restricted Plate HEX, when the shower is on does the boiler get up to temp then cycles on and off?

Going to take the small heat exchange off on Friday when no one is home so its cold and I dont have to rush.

Boiler comes on and stays on all the time the hot tap is running but the water cycles through hot to luke warm.