noisy boiler when just running UFH.. Install a Low Loss Header?

[Pharcycle]

Hi all,

As my plumber seems impossible to get hold of at the moment... or well ever(!) I was hoping I could run something past you knowledgeable folk.

I've been renovating my house and have had wet underfloor heating put in throughout the ground floor (2x zones; front and back), radiators upstairs and a pressurised hot water cylinder. Boiler is an Ideal Logic+ 18kW system boiler.

No complaints about the water or radiator circuit but the boiler is a lot noisier when running just the UFH. Managed to get hold of the plumber who adjusted the bypass and was able to quiet it down a little but agreed it was a little louder than he'd expect so recommended i contact Ideal in case there's a fault. They came out on Friday and after a bit of inspection pointed out that when we opened the valve to the radiator circuit the boiler was a lot quieter.

I guess there's a high restriction with the UFH mixer (Reliance Thermoguard) so when no other circuits are open there's not as much flow through the boiler as it expects. This also tallies with adjusting the bypass and reducing the noise since it allowed more flow through the boiler.

He also worryingly suggested that it would be putting extra wear and tear on the boiler like this so that's certainly far from ideal but currently it's the noise that bothers me most as I can hear it in the bedroom and lounge and since it's meant to be on most of the day this is not great.

The Ideal boiler chap suggested a low loss header might help to decouple the UFH circuit thus allowing the boiler to run at the correct flow whilst allowing each circuit to run as required, does this seem sensible? From what I can see these seems to just be a chamber with a series of Tees for the different circuits. Would I also need additional pumps for each circuit? Do you even need to buy one or just solder a series of 22 mm tees?

Thanks to all for taking any time to read this.
Dave

 

[muggles]

You shouldn't need a LLH on a boiler that size. Presumably it's circulation "rushing water" noise you're getting? A set of close-coupled tees at the manifold end should sort it out. On a more sophisticated boiler I'd suggest turning the pump speed down, but I'm reasonably certain that's not possible on a Logic

 

[Pharcycle]

Thank you for the reply and advice, sorry for the late reply!

The plumber eventually got back in touch, came round and agreed that the system was noisier than expected and also agreed with you that it should not need a LLH.

He was able to track the noise down to the bypass valve and clearly showed my with a screwdriver on it and against my ear that it was the source of the noise. He replaced it today and I can thankfully say that the system is now significantly quieter and there's no audible difference now between the radiator zones and the underfloor heating zones.

I scoured the manual of the Logic+ and there's certainly no method stated in the manual that allows you to adjust the pump speed. I'm not sure if the dodgy bypass was causing other issues with the boiler because up until today I could hear (what I thought was) water rushing through the towel radiator but that has also quietened down. That doesn't make sense to me unless either a) it wasn't a water rushing noise, b) it was vibrations conducting through the pipe / water and being dissipated into the towel radiator (it's probably the first rad in the circuit) or c) some weird flow artefact from the bypass.

Anyway thank you again for taking the time to reply, all sorted here now
Dave