Sludge in Rads

[madge1]

We've got sludge in a few downstairs radiators, and I'd like some advice please.

At the moment we're undergoing building work, and part of that involves a new boiler etc. There's a couple of rooms downstairs where the previous occupants didn't have the heating on, and as a result I think there's sludge in the system.

As part of the new boiler the heating engineer put in a lot of Sentinel. After 4 weeks, the radiators are getting better (a lot better in fact) but there are still some cold spots.

I've asked him to remove the rads and flush them out with a hose. He doesn't want to do this, and instead wants to replace the TRVs on the relavent rads. Despite one of the problem rads having a new TRV last year (and being no better with it).

Surely this is just urinating in the wind, and will have no effect on the cold spot in the middle bottom of the rad? Just don't understand it, as he's been really good with the rest of the install.

thanks

 

[Hugh Jaleak]

Correct flushing of an existing system is a condition of the warranty on a new boiler. Any failure of components in a new boiler may not be covered by the manufacturer if they deem the system wasn't cleaned correctly prior to the boiler being fitted to it. (Powerflushing seems to be accepted method.)

You are paying for the work, insist the work is done to your satisfaction! A new TRV wont eliminate cold spots!

 

[Madrab]

Any new boiler install must have the system cleaned before it's fitted, even brand new rads and piping should be flushed 1st to remove installation debris/flux etc.
If not for a proper all round install then at least to ensure the manufacturers warranty is validated, as they will specify the system is cleaned prior to commissioning. Be that through a chemical mains flush, removing rads in an old system and doing them individually or powerflushing properly.
I can't understand his reluctance to cleaning out the system properly if he's a reputable installer.

Damn, pipped...and wot Hugh said

Is he a builder or a plumber/central heating engineer?

 

[madge1]

he is a heating engineer. With a excellent reputation (and as I say i've no complaints with any of the actual installations he's done).

He's a Accredited Worcester installer, and we've already recieved the warranty acceptance back from Worcester so I'd like to think he's installed it correctly.

When I asked whether they should have done a powerflush before install I got this email back "We have flushed your system and will add flushing agent when all work is finalised". and "only calls for a flush (not power flush) we have and will continue to honour everything required by boiler manufacturers"



It's just on this element that he seems to be dragging his heels - albeit in the same email he did say "The TRVs could be giving problems
pr this may require removing the radiators in question and clearing them in the garden."

But we now seem to be bunging in 100 quid of TRVs when I doubt very much it'll have an effect.

 

[Madrab]

As Hugh suggest, adding new TRV's will not eliminate cold spots, all they do is open and allow hot water into the rad and close when warm enough.
It goes without saying that cold spots are areas of the rad that the hot water cannot circulate to, this is undoubtedly caused by unwanted material in the rad.
Push for the "or removing the rads and cleaning in the garden" direction

 

[madge1]

exactly what I thought! Undoubtedly the Sentinel - he put more in today apparently - will continual to break down the sludge in the radiator so it will slowly get better.

But taking off the rad (or even replacing it) will do the job in a much shorter period of time.

 

[Madrab]

I assume, if he's an accredited installer, that there has been a magnetic filter installed on the return pipe of the system?
He may be taking the direction whereby the added cleaner will eventually move all the magnetite (sludge) into solution and the filter will catch it but unless he has instructed you to clean the filter once a week until what it catches reduces to almost nothing then it's not a satisfactory approach IMO

 

[madge1]

there is a decent worcester filter on the return just before the boiler; again he's cleaned that out today. So that'll help - in the longer term.

I'm tempted to take a radiator off this weekend, then prove to him that the problem is solved in that rad - but now he's installing the new TRVs he'll probably claim that's solved the issue.

 

[Madrab]

Yep, sound like he's going down the, cleaner to dissolve the sludge and filter to catch it, direction. Perfectly acceptable if it sorts the issue but not really an all round job IMO. Much better to clean the whole system out 1st but it is a whole lot more work.

Leave the rads a couple of days after the TRV is fitted if you can and see if the cold spots remain, if so, then hose out the rad and if it miraculously fixes the cold spots then there's your answer.

 

[madge1]

to be honest, if it works, fine. I'll be happy. But it'll take a while unfortunately (the previous occupants let the heating system get in a bit of a state), and we're coming up to the coldest time of year again.

And the fact that he doesn't accept he may not be 100% right rankles. I only wish I was a slightly more competant DIYer when it came to plumbing.