changing radiator valves

Whitegloves

Hi, I am going to drain down my system and replace the old valves with TVR's I have done some basic plumbing and am confident enough to do the job but was wondering what is the procedure for draining and flushing the system?

I am thinking I should open all the rad valves and then open the tail release valve on my lowest rad and hose this out to drain? How should I flush the system to get all the 11 years of gunk out of there? What addatives should I add before refilling and is there any other maintanance should think about when I am at it?

Thanks peeps. :cool:

karl-123

hi you have come to the right place as i am an ex plumbing teacher/manager with 25 years site experience

is your heating system

pressurised or open vent

in other words do you fill the heating from a 5 gallon black plastic tank in the loft or is it filled via a filling loop

eg, a combi boiler or a boiler (with a sealed system as part of the make up)

an expansion vessel, a filling loop,and a 3 bar pressure relief valve to outside either seperate from the boiler or inside the boiler itself

commonly referred to as a sealed system boiler ?

karl-123

to clean the system or loosen the sludge you can use this if you want to ?

http://www.screwfix.com/p/fernox-heavy-duty-central-heating-cleaner-500ml/51463

karl-123

after changing the valves you will be installing this

but make sure you have no leaks " test the system before putting inhibitor in or you will waste it "

http://www.screwfix.com/p/fernox-central-heating-protector/77218

Whitegloves

The boiler is a floor standing conventional boiler. An Ideal Mexico...

karl-123

you will need a radiator spanner " a special allen key that removes radiator tails from radiators "
unless your new valves marry up to the existing tails
personally i try to fit trv`s on the flow pipe " the one that gets hottest first " even though modern trv`s are bi-directional it is not allways possible and is just a personal thing.....
you will be using p.t.f.e. ( plumbers tape for everything lol ) on your radiator tails but a gauranteed water seal on the tail is to use ( loctite 55 a staple of any uk pipefitter ) ptfe string !
as for flushing if you decide to loosen the existing sludge with fernox cleaner for a few days with a filling loop you can use mains pressure to give it a bit of a clean if its tank fed you will have to " block off " the feed and expansion at the tank and then attatch a hose from the mains to the system if you are a bit of a phsyco and want to powerflush hire a machine..........good luck karl p.s. corroded radiator tails can be a pig to remove ...

karl-123

i love mexico boilers " britains favorite floor standing boiler " and for good reason

average life about a hundred years

your system is probably tank fed " does it fill back up again easily "
tank fed systems are notorious for air locks when refilling especially in bungalows ?

1984ReturnsForReal_2

karl-123 wrote: »

you will need a radiator spanner " a special allen key that removes radiator tails from radiators "

Really Karl?

How do you know that?

How about an adjustable spanner?

Just a thought.

1984ReturnsForReal_2

karl-123 wrote: »

personally i try to fit trv`s on the flow pipe "

That is where you do fit them. Its standard not personal.

1984ReturnsForReal_2

karl-123 wrote: »

.
you will be using p.t.f.e. ( plumbers tape for everything lol ) on your radiator tails but a gauranteed water seal on the tail is to use ( loctite 55 a staple of any uk pipefitter ) ptfe string !

Is that an advert Karl?

Whitegloves

What is a tail?

I am thinking of taking all the rads outside and flushing each one individually with the hose or pressure washer!!!

Something I was wondering about was what happens if the new trv is thicker or taller than the existing hung radiators would allow for, would I have to extend or cut pipes to suit for length?? What about thickness against the wall.