CH System Flushing

[solar36]

Hi,

I am new to the forum and new to CH systems. We moved to a large property with c. 15 radiators on a single level operating from an old oil fired boiler. Many of the rads only get hot at only the top 5-10 cm and I was thinking of flushing and refilling with the preventers etc.

I have had some pretty high quotes to power flush it. I would like to take on the task in spring time but not 100% confident.

* Do I need a power flush / demagnetiser or is a hose through good enough? I am prepared to take off most of the rads and hose through individually, as when the system is drained, I also want to replace the TRVs.

* I can see the drain valve on the return pipe but what about refilling - will it automatically refill?

* Where do I insert the cleaning and inhibitor chemicals?

* Can I expect any additional heat output / efficiency?

The boiler has a hot water cylinder and feeder tank in the loft and four pipes to the boiler, two for the CH and two connected to the water cylinder, five pipes going up from the cylinder to the loft. I have not looked at the header tank in detail.

I have had one rad off already and quite a bit of black sludge came out when cleaning.

I have so many questions relating to the system but thought best start with hopefully simple first post! I am deterimined to get the most out of the existing system, insulation and control before throwing money at it for a new boiler.

Thanks in advance for any advice.

 

[Agile]

You need to read a book on flushing!

I dont know of any books but others might!

How much would you be prepared tp pay for one if I wrote one?

Tony

 

[solar36]

Hi Tony,

Yes, a book would be great, if you can recommend one.

In terms of price - I think £25-35 for a comprehensive manual (like Haynes) that is for your type of boiler CH system. I like material to be targetted, rather than do this if you have X, this if you have Y etc.

May include:

General maintenance,

Flushing and protection

Balancing rads

TRVs

Thermostats

Programmers,

RF devices,

Water heating

obtaining optimum heat output and efficiency

and much more!

go for it.!

 

[Agile]

I was thinking of more like £16 because it could command a significant advertising revenue from chemical, filter and pump makers.

Would it be better as an A4 manual or an A5 book or a paperback to take to bed?

Tony

 

[solar36]

A5 would be better, but not essential. £16 is a good price point.
The odd bit of advertising would go down fine, signposting where to get stuff done, what is recommended brands and further reading etc.

Packed with pictures, charts, facts and figures and simple tips to get stuff done.

 

[Andygasman2010]

By all means give it a go but with minimal knowledge it'd be best for you to not spend too much money.

Best thing to do would be add something like Sentinal X800 or Fernox F5 (maybe double-dose it) to a radiator if you can, or via the header tank.

If you add it via the header tank make sure you drain the system off partially to pull in all the chemical.

Run the system as normal for a week or so and see if your cold spots have gone. If not, run the system with only the problem rads turned on one at a time until they all get hot top to bottom. You may find hitting the rads with a rubber mallet helps.

Once they're all fully hot you can then drain off the system a refil. Do this sevral time getting the system up to temp each time then lastly add inhibitor


This is a basic way of doing it and doen't really compare to a proffesional job but it's a cheaper alternative. You may have underlying issues that have caused the sludge in the first place and you'd probably need a plumber to identify these.

Tony, is this book a joke that got out of hand?

 

[solar36]

Hi Andy,

Thanks for the information.

Regarding the filling / header tank, is there a danger of the chemicals getting into the hot water cylinder? Both CH pipes (feed and return) go directly to the boiler. The other two pipes from the boiler connect up to the tank "via" the pipes to the cylinder.

Cheers,

Tony

 

[Andygasman2010]

So long as you've got an indirect cylinder and not a primatic you're ok. If you have one large and one small tank in the loft you have an indirect cylinder, add the chemicals to the SMALL tank only.

 

[solar36]

Thanks Andy, I will check the pipework and report back. Tony

 

[solar36]

Hi Andy,

Have been in the loft. Was not easy to get to the tank as lots of rafters and low head room. Yes, I have a small tank and large tank and the cylinder is an indirect one.

I have mapped all the pipes and stop cocks etc and feel more confident now having been up there.

Plan on draining down in a week or two when I can get some help.

Thanks. Tony

p.s. the small tank looks quite brown and "rusty" inside. Thank is plastic and complete tanks and cylinder were renewed with new loft in 2008 before our time.