Central heating - power flush required ?

[CompoSimmonite]

I intend replacing ALL the house radiators and fitting a new combi boiler (gas aspect will be done by a qualified Gas Safe person). A Fernox TF1 filter will be fitted.
That means all that will be left of the old system will be the pipework.
Is a full power flush needed or would just mains pressure flush be sufficient ?
Cheers

 

[Morris]

Check what the boiler manufacturer requires for the warranty. Ours had to be flushed for the 10 year warranty to be honoured.

 

[JOEPRO]

I'm no expert but I have maintained my 1980s oil heating system for 25+ years. I also replaced the oil boiler myself with a new condensing boiler a couple of years back.

At the time I avoided power flushes incase this caused leaks or damage to existing pipes and fittings inside the house.

My heating system was well maintained by me including rads coming off for flushing about 10 years prior. So whilst the water was black - the system was relatively clean.

My approach was to fit the new filter Magnet on the return line to new boiler. Then to monitor it closely for the coming days, weeks & months. Initially the contamination was fairly heavy first few days. Then the magnet steadily cleaned up until the point where no deposits were being caught. So now I check it every 6 months or so and find only a light coating. Worked for me and the magnet definitely does a great job.

 

[dave h 2]

Kind of hard to do with the rads off

 

[DanZac]

As above. I replaced all our radiators a few years ago (10ish). Before removal I drained and refilled then ran the system with a cleaning product for a few days, then drained and flushed a couple more times before changing the rads.

Pipes that I thought might not have drained that well (there's a couple of downstairs rads that are dead ends) I disconnected the radiators and flushed the pipes separately.

I replaced all the old single rads with double panels and fitted TRV's, which made a huge difference to the temperature of the house, and the boiler coped with.

Post replacement I fitted a magnet thing, ran it with cleaner and flushed again, then inhibiter to manufacturers spec.

10 years on and I top the inhibiter up every year and clean out the magnet thing, but there is very little debris in the system and the magnet never has more than a light coat of black debris on it.

The manufacturer requirement for powerflush prior to fitting a new boiler for the garuntee, is the bit that you get stuck with if your replacing the boiler.

 

[CompoSimmonite]

Just a thought.
Some of the pipework will be replaced and others altered to resite radiators. This is a three bed semi with simple layout.
What is the opinion of also replacing ALL the pipework with Hep20 plastic ?

 

[gaz1]

if you want a proper power flush its all straight pipes cut and taken out of the floor jet washed and brushed

no power flush or mains pressure will clean them properly

once they gunge up they will lower the flow and no amount of cleaning other than cut take out and clean them will do it

i dont like plastic as copper outlasts them and the connections as well

plastic connections are a replacement part and they will leak in time

 

[bricol]

I did a mains pressure (high around here) flush of the systems using the connections where one rad was removed -other than soaking the bedroom wall when the hose clip failed, it didn't do much.

Sticking a Fernox filter in the system (cheap at the time) pulled loads of magnetic crap out in a few weeks - cleaning every few days. Tailed off until it had nothing on it year to year.

 

[OJCar]

Check what the boiler manufacturer requires for the warranty. Ours had to be flushed for the 10 year warranty to be honoured.

This.

We had a new boiler fitted in the autumn, flush was needed for the warranty.

 

[CompoSimmonite]

When be bought the house, 42 years ago, the central heating was installed with very messy microbore. I therefore replaced it with 15mm. All that remains of the original, approx 45 year old, pipework is the main 22mm pipework. Never had a leak other than minor weep at compression fittings of divert valve.
I know copper isn't cheap but do people reckon it'd be worth replacing everything (and recouping some of the cost by weighing in two copper cylinders and pipework) ?

 

[dave h 2]

This.

We had a new boiler fitted in the autumn, flush was needed for the warranty.

If you have trouble with the new boiler whistling on an existing system the power flush is the first 'get out' they will use.
Replacing all the pipes gives you a chance to rationalise the layout, lot of work though.

 

[gaz1]

Check what the boiler manufacturer requires for the warranty. Ours had to be flushed for the 10 year warranty to be honoured.

as a boiler company i wouldnt honour the boiler warranty fitted to an old system as im not sure the state of that system in the first place

as a plumber ive seen really bad states of gunged up plumbing pipes

this pic is why i wouldnt honour a new install within old radiator system



that stuff within the boiler parts and they are really refined nowadays and those boiler parts are going to fail for fun

 

[hunter27]

Stick with the copper pipe and extend / alter the system if necessary in copper. No one ever removes all the pipework cuts it into straight lengths, jet washes and brushes it then refits it
When the benchmark book is filled in with your installer he will have to state what he has done re flushing and inhibiting the system, if you have to get the manufacturer in to a fault that could be related to the system water being dirty they will take a sample to check before working on it.

 

[dobbslc]

The old cylinder in my house.

I could push my finger through the bottom of it when I took it out.
Very close to a kitchen full of water

 

[Morris]

as a boiler company i wouldnt honour the boiler warranty fitted to an old system as im not sure the state of that system in the first place

as a plumber ive seen really bad states of gunged up plumbing pipes

this pic is why i wouldnt honour a new install within old radiator system

View attachment 488215

that stuff within the boiler parts and they are really refined nowadays and those boiler parts are going to fail for fun

Whether you would honour it is irrelevant. If the boiler manufacturer requires a power flush for the warranty then that's your part of the bargain kept, you have complied with their condition.

 

[brightspark]

i got a new boiler fitted just filled the system with centinel sludge remover and ran for a week /drained the full system took all radiators off flushed them out with a hose pipe outside . fit new thermostatic valves new boiler fitted with a magnatec refilled it and added the fernox inhibitor and its been ok since for the last 9 years just clean the filter every year . none of the pipes have krap in them and all rads get hot

 

[Ross365]

I'm planning to have a new boiler (oil) fitted this summer. I think my system is at least 40 years old (it was here when i bought the house in 1993). I've changed the Fernox inhibitor at regular intervals (and the water is clear) but I've never flushed it.

Is there anything I could start to do now to help it easier to flush when the contractors arrive?

 

[gaz1]

no point until the weather changes to being warmer

then strip down and flush all you can do, down each rad pipe cap and then move to the next rad until all are done and then repeat

 

[Morris]

I'm planning to have a new boiler (oil) fitted this summer. I think my system is at least 40 years old (it was here when i bought the house in 1993). I've changed the Fernox inhibitor at regular intervals (and the water is clear) but I've never flushed it.

Is there anything I could start to do now to help it easier to flush when the contractors arrive?

This is pretty much how our system was. I changed the inhibitor religiously and when the system was flushed virtually nothing came out. The new boiler has been in four years now and every service the magnetic filter is clean.
I'm no expert but I doubt that there is anything you can do over what you have done.

 

[DanZac]

Is there anything I could start to do now to help it easier to flush when the contractors arrive?

Not my normal stance, but I'm a firm believer in "if you're going to pay someone to do a job, then let them do the whole job".

You can almost guarantee that whatever you do in advance wont be what the contractor wanted or would have done, so let them do it the way they want to do it and to a standard that they're happy to guarantee.

There's no point paying someone to do something and then doing half of it yourself.