New Central Heating System, Need Flushing?

Eastender

We're taking out old system boiler and fitting a new combi boiler, Vaillant eco tec plus 831, replacing all old rads having a bigger 22mm pipings.

Now the installer thinks that because it's a new heating system, it does not need a flush, but I'm doubtful. Also he seems not keen on installing a filter and inhibitor.

warmhands.coldheart

Easty, seems like your going through all the issues I've been through.. I insisted on having the system flushed and Inhibitor added..... just in case.... plumber had all the gear anyway.. didn't get the filter fitted in the end as thought other two would be sufficient.

gas4you

If there are any old pipes left they will contain crud and need X800, or the equivalent, to flush the system

If all pipework and rads are new, then you will need it flushed with X300 or equivalent.

You are always best off having a magnetic cleaner of some sort fitted as not fitter will EVER get a system fully clean with a powerflush. 80-85% clean on a good day.

Are you sure they don't mean increasing the gas supply pipe to 22mm?

Eastender

gas4you wrote: »

If there are any old pipes left they will contain crud and need X800, or the equivalent, to flush the system

If all pipework and rads are new, then you will need it flushed with X300 or equivalent.

You are always best off having a magnetic cleaner of some sort fitted as not fitter will EVER get a system fully clean with a powerflush. 80-85% clean on a good day.

Are you sure they don't mean increasing the gas supply pipe to 22mm?

Pipes were smaller size before and he said it will need to be upgraded to 22mm. Surprised to learn that even with a new rads and new pipes, it needs to be flushed. If not flashed, can I insist that he fits a magnetic cleaner (filter?).

keystone

Eastender wrote: »

Pipes were smaller size before and he said it will need to be upgraded to 22mm.

That will be the gas pipe and thats all to do with flow rate. The new heating pipework will require some parts to be in 22mm but by no means all of it. If he want to do the lot in 22mm I doubt his motives tbh.

Surprised to learn that even with a new rads and new pipes, it needs to be flushed.

Of course it does. The reason for flushing it is to remove the products of installation - bits of wire wool, flux, shards of copper, bits of solder - which will be in the pipework and are inevitable. These need to be removed because they will only hasten corrosion of the system if left in. It doesn't necessarily mean powerflush either - as G4U has said X300 will get this stuff out.

If not flushed, can I insist that he fits a magnetic cleaner (filter?).

The latter is not a substitute for the former and is only efficacious if installed on a clean system in the first place.

Regarding the flush you may find that the boiler manufacturer will void your warranty if the system is not flushed after installation whatever the mores of the installer. That should be sufficient incentive!

He should know better. If he won't do it then find a new installer.

Cheers

gas4you

You are the customer, paying your good money for his services.

You can have whatever you want fitted if you want to spend more money.

Eastender

keystone wrote: »

That will be the gas pipe and thats all to do with flow rate. The new heating pipework will require some parts to be in 22mm but by no means all of it. If he want to do the lot in 22mm I doubt his motives tbh.

Of course it does. The reason for flushing it is to remove the products of installation - bits of wire wool, flux, shards of copper, bits of solder - which will be in the pipework and are inevitable. These need to be removed because they will only hasten corrosion of the system if left in. It doesn't necessarily mean powerflush either - as G4U has said X300 will get this stuff out.

The latter is not a substitute for the former and is only efficacious if installed on a clean system in the first place.

Regarding the flush you may find that the boiler manufacturer will void your warranty if the system is not flushed after installation whatever the mores of the installer. That should be sufficient incentive!

He should know better. If he won't do it then find a new installer.

Cheers

Thanks for explaining so clearly.:A

When we're living in a coucil flat and had an old combi boiler replaced to a condensing combi and upgraded 3 rads.

The council contractor did not flush the system, when I asked them he said the water was clean which he demonstrated with the pipes and then they fitted a limescale filter instead of a filter for preventing metal particles.

At least I'll insist on flushing the system and fitting a filter like Fernox TF1, to increase the life of the Vaillant and reduce breakdowns.

cyclonebri1

It's as Keystone said, there will be all sorts of wire wool fragments, bits of rad thread and all the other stuff. If not it can react with copper It needs to be flushed, insist on it.

The bit about invalidating warranty is very true should anything fail.

I expect he's talking about increasing or lengthen the runs of 22mm copper as the 15mm branches are too long to adequately feed the rads, could be gas pipe though.

Check that he has done the gas feed calcs to ensure you have the correct feed to the new boiler.;)

southcoastrgi

+1 on the above