Brennan and Son Plumbing & Heating

Brennan and Son Plumbing & Heating Brennan & Son is a plumbing and heating company based in Southampton. It is a second generation family business. Gas Safe registered since 1985.

A lovely photo taken by our customer/friend when Heather Brennan turned up at the door. Third generation Brennan coming...
09/05/2026

A lovely photo taken by our customer/friend when Heather Brennan turned up at the door.
Third generation Brennan coming through.

What does happen during a boiler conversion? Here we see the replacement boiler going in a kitchen cupboard, pipework u...
05/03/2026

What does happen during a boiler conversion?
Here we see the replacement boiler going in a kitchen cupboard, pipework under the floor and new gas line to the gas meter. Also change of pipework in the loft and in the airing cupboard. Justin and Sarah have come to see how Luke is getting on with his job today. Nice work Luke 🙂
Soon to be a Worcester 28CDi Compact Combi Boiler

How many different kinds of sludge are there??Here we see the black chunky kind with lumps of metal.The orange kind from...
21/02/2026

How many different kinds of sludge are there??

Here we see the black chunky kind with lumps of metal.

The orange kind from steel pipework.

The blue kind with heavy scale deposits.

And the muddy clay type.

All this silts up the small gaps in the radiators & heat exchangers. It gets in moving parts like the pump and diverter valve. It rubs on the rubber membrane of the expansion vessels and seals. All extinguishing the life expectancy of your boiler and reducing heat output.

We do an Adey Procheck with every service to test and let you see the colour of your central heating water.

Let us know if you want a boiler service or your central heating system tested and cleaned.

Why does my water go hot and cold?This is a plate to plate heat exchanger we find in a combination boiler. We see the cl...
21/02/2026

Why does my water go hot and cold?

This is a plate to plate heat exchanger we find in a combination boiler.

We see the clean side where hot water flows and we see the other side blocked with black lumpy sludge from the central heating and radiators.

The heat exchanger has alternate plates of cold water and central heating water one after another. The boiler uses the central heating water from the radiators to heat the cold water by pushing it through the thin gaps of these plates and allowing heat to transfer.

Older boilers used to have bigger gaps but weren’t as efficient. Modern boilers are much more efficient but only when the water isn’t dirty.

In the photo, we see the sludge is fully blocking the plates. That makes the plate heat exchanger overheat and the boiler stops heating. When cold, it heats again and the process repeats with the boiler cycling hot, then cold and you jumping in and out of the shower! 🥵 🥶 🚿🛀🏻

Ooo a lovely photo from this morning showing how sludge builds on the inside of the pipe. I tell people, it’s just like ...
16/02/2026

Ooo a lovely photo from this morning showing how sludge builds on the inside of the pipe. I tell people, it’s just like cholesterol. It reduces flow and eventually causes a complete blockage and boiler failure.

If you have had trouble with your heating this year. Get in touch about a free visit.

12/02/2026

What even is sludge?
Here we see a magnet being put into the F&E tank on a dirty open vented heating system. Immediately, the magnetite is visible.

That can have a massive effect on moving parts and thin gaps in your boiler, pipes and radiators.

Let us know if you want a chemical clean and powerflush - It can reduce your fuel usage and bills and make your house warmer!

How rusty is your central heating? Here we see an almost beatifully sludged pump, a furred up F&E tank and a radiator ru...
12/02/2026

How rusty is your central heating? Here we see an almost beatifully sludged pump, a furred up F&E tank and a radiator rusting from the inside out (which caused a leak).

We do an Adey Procheck with every boiler service to check your water quality. Let us know if you want your water quality checked.

Seasons Greetings and warmest wishes from us at Brennan & Son 🎄💃🌟
24/12/2025

Seasons Greetings and warmest wishes from us at Brennan & Son 🎄💃🌟

That’s a wrap! Completion of DIY SOS, a renewed house and one very happy family. Thank you Eastleigh College for taking ...
15/10/2025

That’s a wrap! Completion of DIY SOS, a renewed house and one very happy family. Thank you Eastleigh College for taking our apprentice Luke Bird and us on this fantastic journey. Lovely to meet so many amazing people!
What a community we have.


Address

Southampton

Opening Hours

Monday 9am - 5pm
Tuesday 9am - 5pm
Wednesday 9am - 5pm
Thursday 9am - 5pm
Friday 9am - 5pm

Telephone

+442380225566

Website

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