DIY on a combi system

[DarrenSL]

Having done a few Google searches, most DIY sites discourage the DIYer from touching combi system stating that professional help should be sought.

I was planning to replace my bathroom radiator which would involve a partial draining of the system. My original understanding was that this would be quite a simple process...

(i) switch off power to boiler
(ii) switch off water supply to boiler
(iii) open rad valves and bleeds upstairs
(iv) open the stopcock under the boiler until water in the system is at a sufficient level for work to be carried out.

To refill, switch water on and bleed all radiators.

What can possibly go wrong!

 

[doitall]

It took me 5 years to learn that

 

[doitall]

As you say turn everything off and drain the radiators out through the draincock on the lowest one.

But first find out how to fill it back up again

 

[Paul Barker]

do 4 before 3.

loads of other things can go wrong. Use your intelligence to deal with each situation as it crops up.

 

[DarrenSL]

Thanks for the prompt responses!

I was losing confidence reading 'seek profesional help' all over the place. Presumeably, its to stop fools from draining their system whilst switched on!

 

[DarrenSL]

Use your intelligence to deal with each situation as it crops up

Perhaps I should seek professional help afterall.

 

[Agile]

What you want to do is very simple and many DIyers do it without any problem.

Reading these forums there are many plumbers who have qualified on the four week course and do it and get problems which they cannot resolve. They leave the client without any heating or hot water and post pleas for help here.

At least if you have any problems you will only have an annoyed wife and not a litigious client to bother about. A bunch of flowers and a meal out will probably sort her out!

Tony

 

[ChrisR]

Things can always go wrong - one of the endearing features of plumbing.

"Stopcock" in iv), under the boiler may not be what you want - look for a drain cock on the boiler, which will be a very small thing. Depending on which type you have you may be able to use the filling loop to let water out, don't use the pressure felief valve or it'll leak. Drain cock on a pipe somewhere is usually a better bet, but they can give bother too!

 

[doitall]

Just to add to what Chris said about draincocks

I always fix the hose and open the draincock with the system water turned on as it will release the washer if its stuck.

 

[DarrenSL]

Thanks for the tips. I'll have a stab at it later in the week and let you know how I get on.
First things first, I'll get hold of that emergency plumber number. Just in case

 

[geoff@cetltd]

don't forget to replenish the inhibitor

 

[ChrisR]

Put something under the draincock, it'll leak...

 

[DarrenSL]

don't forget to replenish the inhibitor

My plumber told me that I didn't need inhibitor when he replaced my boiler 2 years ago and converted my 20 year old gravity fed microbore system to combi. I thought it was odd at the time but took his word for it.

He also fitted trv's to all the rads. I assume thats because the boiler has some sort of cross over valve? (Worcester Platinum)

 

[geoff@cetltd]

Well, there are people in here who are better placed to answer that than me

I certainly have some in mine

 

[Gasman1015]

Your plumber was telling porkies.
Add some to the system before refilling.
No room stat either then.? Plumber was a lazy git as well.

Worcester Platinum.. no such animal.