Now worried - filling loop/backflow in combi boiler, 'sweet' smell to water

[Kalypso]

We have been renting our property for 6 months. For the past few weeks I have noticed a 'smell' to the water when having a shower. It's hard to describe but a faint sweet, swampy smell - the nearest thing I can liken it to is the smell of damp sugar beet, or like a diabetic person's breath. I didn't think much of it, as we've moved recently and I don't like the water here much anyway.

However, recently our boiler has been cutting out. We've had to turn the hot taps on increasingly hard to get hot water, and if they're not blasting out water (and as of yesterday, we're now having to turn them on full volume and soak the kitchen in the process) then the boiler cuts out and the water is freezing again. I 'm now smelling the 'sweet' smell from our kitchen tap - this may be because so much water is coming out, like it would in the shower, so I can smell it more easily. There is no taste to the water (apart from the chlorine!)

I rang our water supplier for information and the first thing they picked up on was the pressure problems with our boiler, explaining that a problem with the filling loop could create backflow and that's potentially a health hazard. I'd already called our agent this morning about the boiler and when I called again this evening for an update, they explained that they were waiting to hear back from the landlord. I mentioned what the water supplier had said and they said this was an issue that meant they could get a plumber to us straight away.

It's good it is being treated with urgency, but now I am really worried about chemicals in the water. We have a 2 year old who has been behaving a bit erratic lately and now I am freaking out!

Can anyone tell me more about what this could mean, please?!

I don't know, is my answer. But I do know that it is fairly common for animals or birds to fall into water tanks in attics, and that was my first thought, so get the plumber to check for any dead things in the tank.

The filling loop should be disconnected while not in use to comply with water regs. That said contamination is a rare event even if left connected. Try not to worry! The hot water problem could be a diaphragm in the flow switch which is another easy fix

Thank you both for replying so quickly. Hellymelly, I don't think we have a water tank as it's a combi boiler. But your suggestion reminds me of a friend (in a rural location) whose water supply got partially blocked by an enormous dead frog in the pipes. They'd been drinking froggy water [bleugh]

Saltycopporn, thank you - at least there is another possibility (diaphragm in flow switch) and it's good that contamination is a rare event. Fingers crossed.

the filling loop should have a valve at each end, they should both be closed except when topping up, and preferably the loop should be disconnected at one end so there is no possibility of the mains and the boiler passing water to each other at other times.

Watch the pressure gauge on your boiler, what does it read, and how much does it vary? It can go up a bit when you have the heating on and all the rads are hot, and down when cold, but should not vary at other times.

there will be a pressure relief valve which normally releases water through the wall behind the boiler, ands is turned back on itself so it causes an unsightly stain on the brickwork. Is there a water stain on the outside of your house behind the boiler?