How do I increase pressure in my boiler?

To increase the pressure in your boiler, locate the filling loop under the boiler. Open both valves to let cold water flow into the system until the pressure gauge reaches 1.0–1.5 bar. Always monitor the gauge and close both valves once the correct level is reached.

Why is my boiler losing pressure?

The most common cause of boiler pressure loss is bleeding radiators, which releases water from the system. Leaks in the boiler or pipework can also lead to pressure drops. If pressure drops repeatedly, call a Gas Safe engineer.

Why are my radiators warm even when the heating is off?

If your radiators are warming up without the heating being turned on, it is likely due to a faulty anti-gravity (check) valve that is allowing heat to circulate naturally by convection. A Gas Safe engineer can replace the valve.

Are you Gas Safe registered?

Yes. A.S. Plumbing and Heating Engineers is fully Gas Safe registered (ID: 211549). By law, all gas work must be carried out by a registered engineer. You can verify our registration at gassaferegister.co.uk.

Do you offer 24/7 emergency plumbing and boiler repair?

Yes. We provide 24/7 emergency plumbing and boiler repair services across Dewsbury, Wakefield, Halifax, Bradford and Huddersfield. Call 07866 623870 any time of day or night.

Power Flushing Services Dewsbury

Honest Diagnosis

Do you actually need one?

We would rather tell you the truth than sell you a flush you do not need. The signs that genuinely point to a dirty system are:

Radiators cold at the bottom and hot at the top. This is the classic one. Sludge is heavier than water and settles at the bottom of the radiator.

Some radiators never get hot while others in the same system do

The system takes a long time to warm up from cold

Black water when you bleed a radiator or drain a valve

Noisy pipes or a kettling boiler

The boiler keeps cutting out on overheat because circulation is poor

The pump has failed more than once

You are fitting a new boiler onto an old system — most manufacturers require the system to be clean

What is not a sign you need a power flush:

Cold at the top, warm at the bottom. That is trapped air. Bleed it.

One radiator cold when everything else is fine. Usually a stuck valve or balancing.

A newly installed system. It should not need flushing for years.

If we come out and the system does not need a flush, we will tell you and charge you for the visit, not for a flush.

Step-by-Step Procedure

How a power flush works

1

We test the system water to confirm the level of contamination and check inhibitor levels

2

A pumping unit is connected to the system, usually at the pump or at a radiator

3

Cleaning chemical is introduced and circulated at high flow, with flow reversed repeatedly to shift deposits

4

Each radiator is isolated and flushed individually, agitated where needed

5

The system is flushed through with clean water until it runs clear

6

A corrosion inhibitor is added to protect the system going forward

7

A magnetic filter is fitted if there is not one already — this catches future magnetite before it circulates

8

The system is refilled, rebalanced and tested

Comparison

Power flush or chemical flush?

Chemical Flush

A chemical flush means adding a cleaner to the system, running it for a period, then draining and refilling. It is cheaper and it helps a mildly contaminated system.

Power Flush

A power flush uses a dedicated high-flow pump with flow reversal, which physically shifts deposits that a chemical flush will not move.

For a moderately or heavily sludged system, a chemical flush is a waste of money. For a lightly contaminated one, it may be all that is needed. We test the water first and recommend accordingly.

Fixed Written Quotes

Priced by radiator count · No surprises

Pricing Transparency

How much does a power flush cost?

It depends primarily on the number of radiators and how badly contaminated the system is. We offer clear pricing based on your radiator count (e.g. up to 6 radiators, 7 to 10, 11 to 15, or larger systems).

Call us with your radiator count for an immediate, fixed quotation across West Yorkshire.

Call 07866 623870 for fixed power flush pricing

How long does it take?

For a typical domestic system of eight to ten radiators, most of a day — usually four to six hours. A larger or heavily sludged system can take longer. We do not rush it, because a flush that is stopped early is money wasted.

Magnetic filters

A magnetic filter fitted on the return pipe into the boiler catches magnetite continuously, and it is emptied at each annual service. Fitting one after a flush is the difference between the system staying clean and slowly silting up again over the next five years. Most boiler manufacturers now expect one to be fitted.

We fit MagnaClean filters as standard on installations, and we can fit one to an existing system on its own.

Questions & Answers

Frequently asked questions

Is a power flush worth it?

If your system genuinely has sludge in it, yes. It restores radiator output, reduces the load on the boiler and pump, and prevents the kind of failure that ends up costing far more. If your system is clean, it is not worth it, and any engineer who recommends one without testing the water first is guessing.

How long does a power flush take?

Most domestic systems take four to six hours. Larger or heavily contaminated systems can take a full day.

How often should a system be power flushed?

There is no fixed interval. A system with a magnetic filter and correct inhibitor levels, serviced annually, may never need another one. A system with neither may need attention every five to eight years.

Will a power flush fix a leaking radiator?

No, and it can occasionally reveal a leak that corrosion was plugging. If a radiator is badly corroded internally it may be better replaced than flushed. We will tell you if we think that is likely before we start.

Do I need a power flush before a new boiler?

The system must be clean before a new boiler goes on, and most manufacturers make it a warranty condition. Whether that requires a full power flush or a chemical clean depends on the system's condition, which we test.

What is the black sludge in my radiators?

Magnetite — iron oxide produced as the steel inside your radiators corrodes in contact with water. It is magnetic, which is why magnetic filters work, and it is the single most common cause of poor central heating performance.

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