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Plumbing

Will a Powerflush cure a groaning noise when central heating pump in operation?

Anonymous user 03/03/2024 - 3.04 PM

We have a Vaillant combi boiler and recently had a loft extension an had a megaflow type system installed to ensure there was sufficient hot water on demand. About 6 months the pump began to make a racket. We have a boiler service contract with BG and they replaced the pump. Ever since then the boiler has made a kind of continuous groaning noise when the when heating is on but only when the pump kicks in AND the pressure guage on the boiler always goes into the red. We've had BG back about 3 times and each time they drain off some water in the system to relieve the pressure and bleed the rads - but we've never been told what's causing the groaning noise or why the pressure guage is in the red when the heating is on. The last engineer said he drained the system and removed a lot of sludge from the system - I'm not sure how he did this as I wasn't at home. He said we needed to have a powerflush and fit a filter. We've received a quote of £720 inc. VAT from BG!! We moved into the house in 2007 and have replaced all of the rads (8 Acova column rads and 2 towel heaters). All the rads heat up perfectly well, although you do need to balance the rads quite carefully to get them to heat up evenly on each of the ground, first and second floor. Will a powerflush + filter solve the groaning noise and stop the pressure gauge hitting the red? I am more than slightly dubious and feel like BG are simply "upselling" something I don't need and trying to take me for a mug... a £720 mug! I just want the system to stop making the noise and pressure gauge to remin in the grey zone - typically my 10 month old daughter's bedroom is above the boiler and it wakes her up every time the pump kicks in! Any thoughts/comments would be gratefully received.

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3 Answers

Anonymous user

Hello there, personally I feel £720 is a steep price to pay on the size of your system you should really be looking at no more then £350-£500. Whether this would fix your problem is another matter. I'm not saying it isn't sludge however it could be air in the system causing noises, has the engineer checked the expansion vessel pressure? Sometimes if pressure is low, the expansion in the system when hot can cause it to go into red, I doubt sludge would cause the hitting red problem. Does pressure go up instantly when switched on after a while as system heats up? I know this may sound a silly question and I'm sure you have checked, but has the filling loop been checked in case its letting by? Hope the above helps and good luck Regards, John. P.S are the pump valves fully open?

Answered12 January 2014

D & R Property and Plumbing Maintenance

Rating: 4.9 out of 5

New Romney

the expansion vessel may be undersized and that is causing your problem.

Answered14 November 2020

Mend Your Home

Rating: 5 out of 5

Crawley

Hi, It's likely a faulty expansion vessel when it's broken or flat there no place to absorb pressure. When the water heats up it expands but no expansion vessel means it will just increase pressure including when the pump increases pressure. I suggest reviewing your contract you likely get basic servicing, consider asking if you can have your servicing done by a local business. As for a "strip service" every 4 years with inhibitor. A well maintained system shouldn't have sludge. You need better servicing and maintenance. The noise is likely air trapped in the system, bleed some radiators. Maybe an upsell I'm ex BG, the engineer that books this flush gets a commission on a special app they called CTap. The contract is similar to insurance like car insurance, My understanding is when they return for a repair it may effect the cost of your contract in future.

Answered26 December 2023