I don't have a filter.

Anyone got any tips for how to descaling my gas hot water boiler and pipework.

Nope. But our water is piped into a 1000ltr holding tank in our utility room, then pumped into the house. Because of the tank it seems to allow the lime and any sediment to settle out of the water to the bottom of the tank. This helps greatly with scale in appliances, with an inline filter to the water dispenser in the fridge we even drink the water, never bothered with bottled at all.

Acid should remove it, but there could so easily be complications.

Is this a small Ascot type of heater or one that does the central heating as well?

Your right. Can't remember name but it's readily available BUT as you say it has its risks as it tends to find weakness.
Usually, if the boiler has got to the point where it's not working properly due to scale it's curtains in which case you have nothing to lose with the acid.

Yes it is a small Ascot type, hot water only.

Agua fuerte should do the job, not sure how you put it in there though

If so then it will be hard to clean again. It could well mean complete dismantling.
Not a job I would want to tackle.
When you have found a solution maybe purchase an in-line filter. Which one I do not have a clue but you should find one that adds a salt solution/chemical thing not just a particle filter.

Basically, that is a water softenner. It's a resin filter that captures the calcium ions, and you then use salt to flush the Calcium ions to waste, and replace them with Sodium ions.

As for the acid. I would use the Salfumante/agua fuerte which is hydrochloric acid, HCl and is available in Leroy's very cheaply. andle with care, it is very strong, so you might want to dilute it.

I use this with an old toothbrush to remove calcite/calcium deposits round taps etc. It is like cilit bang but a hundred times stronger, so don't leave it on too long. It will also take calcite stains out of toilets. Don't leave it on stainless for long as it will stain it black.

I would basically let it flow thru the heater and then wash water thru it after.

If the heater is knackered then you have nothing to lose.

Thanks for your responses guys. The heater is quite cheap to replace, has anyone any experience of descaling copper pipework?

No. However it's not the most difficult concept. Take a small piece of scrap copper, and try immersing it in acid of varying strengths, and see if it is weakened. That experiment can then be used to judge how long it is safe to have the acid in the pipe.

A layer of calcite is a good thing in copper pipes as it prevents the copper from dissolving into the water.

Make sure you run a good volume of water thru the system afterwards, obviously.

Yep this shift limescale but make sure you flush the system well afterwards

Just seen this, it's easy vinegar in it over night you will here it hissing, white vinegar preferably 20%. I just did mine, works a treat and cheap as chips

Yeah, but agua fuerte is faster and also cheap as chips.

doesn't smell like them though - unlike vinegar