Central heating upgrade - flush or not to flush

[WELLY417]

Hi
We are currently upgrading our heating system from a back boiler to combi set up. Corgi bloke is going to be doing just the gas fittings and installing the boiler. The rest will be DIY.
Was planning to flush the system but now wondering if this is worth the effort? Reason being that all the radiators will be coming off because of plastering / moving and adding radiators / fitting TRVs and we will be hosing all the crud out of the radiators before refitting. I have read that sludge builds up pretty much just in the radiators so, having cleaned them all out (and will also be installing a Magna clean filter) is a system flush necessary?
Best guess is existing system about 15 years old and what we drained off when removing radiators looked pretty clean and seemed to have inhibitor added.
If plumbing experts out there still think a system flush is needed, then I could do with advice on:
1) All radiators are currently removed on ground floor. Is there any way of flushing out the pipe work without having to refit all the radiators to do it?
2) Flush before or after new boiler & TRVs installed (or both!)
3) Product recommendations for flush?


Any replies much appreciated.

 

[Bahco]

As I have been previously informed, your boiler warranty is validated by having a powerflush.

I think it is a good idea if you are planning on staying in the house for yrs.

Choice is yours on whether you wish to fork out for one.

 

[Agile]

I think he is not thinking anout a power flush just a flush!

All that is required is that the system is clean. How you achieve that is up to you.

If its clean then why do you want to waste £100 on a Magnaclean which does not trap anything which is non magnetic!

My suggestion would be to flush as best you can with mains water and then run the system with X800 for a few hours and then drain and add X100 and that should be fine IF its as clean as you say!

Tony

 

[JohnD]

even after washing the system out and adding a Magnaclean, a lot more grime will be loosened if you add a chemical cleaner such as X400. If you have already fitted the magnaclean, it will trap the loosened stuff and prevent it re-settling in nooks. It is a good idea to add and circulate this for a week or so before you start washing out the rads as it will make the sediment loose.

 

[AlanE]

I have read that sludge builds up pretty much just in the radiators

Wrong!! And if you have microbore pipes the crud can easily block them or at least reduce the flow.

With waranty repairs affecting the heat exchanger the manufacturer may well carryout a water analitic check to confirm if it has been properly flushed. If not no waranty - after all correct flushing is part of the installation instructions.

 

[WELLY417]

Many thanks for all the comments. Seems like i will be doing a flush after all. I wasn't trying to say the system is squeaky clean, just that the sludge that is in the radiators seems to have settled at the bottom of them and that the circulating water looks clear to the eye.

Still a bit confused on when to flush ? By my way of thinking it would make sense to do it before new boiler is fitted to avoid crud getting into it. However, have also heard that flush is required after upgrading the system because bits get in from the new fittings (quite a lot of pipe work will also be replaced due to moving radiator positions).

If a flush is needed before fitting new boiler, the main problem will be having to refit all downstairs radiators before adding the system cleaner. There are no radiator hanging brackets in place and the walls need replastering so rads would have to be removed again after flushing (corgi guy booked a while back to come this week. Walls should have been sorted by now a ready to fix rads. Long story .... builders) So, if anyone can come up with an alternative way to clean system without putting rads back on it would save a lot of work.

Last thing - on the Magnaclean. Fitting it because i assumed DIY flushing will not get system 100% clean and this would help with the rest. Also, at £60 (e-bay) a lot cheaper then paying for a power flush. Waste of time / money?

 

[Agile]

I would say that if the system is properly cleaned then a Magnaclean is not necessary.

If anyone does fit one then it should have a gauze filter washer on the outlet as it does not attract lime based dirt.

A magnaclean is often fitted by someone who is not properly cleaning a system.

Tony

 

[JohnD]

this gauze filter for lime... how do you fit it, and where does it come from?

 

[clf-gas]

A magnaclean is often fitted by someone who is not properly cleaning a system.

Tony

A bit harsh is that Tony, I would say a Magnaclean is fitted to keep systems clean. As you already know a powerflush is not 100% no matter how professional you are.


Ho and a guase lime filter, Ive never seen one, got a link to some info, TIA.

 

[Agile]

They are sold by BES for 23p but often used on washing machine hoses so many washing machine shops sell them.

Just a rubber washer with a domed gauze centre. Essential if you fit a Magnaclean and I am surprised Chris Adey does not supply them with his products.

Tony

 

[corgiman]

A magnaclean is often fitted by someone who is not properly cleaning a system.

Tony

A bit harsh is that Tony, I would say a Magnaclean is fitted to keep systems clean. As you already know a powerflush is not 100% no matter how professional you are.


Ho and a guase lime filter, Ive never seen one, got a link to some info, TIA.

I agrewe with clf Tony that is a bit harsh

we fit boiler buddies as standard now as not matter how well or how long you powerflush you are going to miss bit as we like a bit of added protection with a visual aid for the customer so they can tell us if we need to come back and flush it again.

Sorry but from what I have seen powerflushing is at best OK and slightly better than the way I used to flush for years

X400 four weeks and a hose pipe

 

[clf-gas]

They are sold by BES for 23p but often used on washing machine hoses so many washing machine shops sell them.

Just a rubber washer with a domed gauze centre. Essential if you fit a Magnaclean and I am surprised Chris Adey does not supply them with his products.

Tony

Argh!! With you Tony

Stopping loose flakes of limescale from within the pipe

 

[gas4you]

My suggestion would be to flush as best you can with mains water and then run the system with X800 for a few hours and then drain and add X100 and that should be fine IF its as clean as you say!

Tony

If your new boiler has an aluminium HE then DO NOT flush with X800 for more than 3 hours absolute maximum, unless you want to fit a new HE

Flush with X800 before you remove the old boiler, then when clean fit new boiler and just hot flush as per MI's then drain and refill with a good quality inhibitor such as Sentinel or Fernox

 

[croydoncorgi]

What's not been mentioned yet is that the pipework at the lowest parts of the system (ie. under the Ground floorboards) will probably contain some or lots of sludge. If you can arrange to disconnect pipes in that area (and having made sure there are no opens anywhere else!), you can flush the primary Flow and Returns with a hose from the new boiler position BEFORE you actually connect it. Especially if you've circulated some X400 for a while using the OLD boiler, pump etc., most of the sludge collected in the pipework should come out quite easily. If it's impractical to connect a drainhose onto the opens under the Ground floor, if there are no electrical cables at risk, it makes little impact if a small amount of water flows out onto the ground under the building, especially in the summer, and the sludge will quickly dry out and cause no problem down there. Could be argued that it's preferable to putting it down the drain and screwing-up the sewage plant! (Assumes you are actually at ground level!!!)

 

[samthediyman]

Tony: I think all the boiler manufacturers, the power flush association, kamco, fernox, etc. all disagree with you. So much that manufacturers do not work on boilers that have not been power flushed; as sludge is related to 80% of breakdowns. There is no current better ways to clean your system from sludge.