Interesting day for my CH...

[wildebeest]

It all started yesterday with a popped 3A fuse on the domestic heating/HW system. The Potterton Suprima 30 which has had its brain removed and replaced with a board with a black button rather than the flush reset button was flashing like a Christmas tree.

The fuse was duly replaced after first checking to see nothing was on fire.

Boiler fired, great I thought as I was running the hot water. I've not got a thermometer but it was way above the 60degrees the tank is set to. Radiators still cold, even with demand.

Boiler cuts out after 2 minutes so I think hey up, somethings wrong. This morning, before phoning British Gas(homecare contract) I thought I would see if it fires. Noises like an empty builders skip being dragged across tarmac from the pump and I quickly shut the whole lot down.

Gas man arrives and deduces a failed pump - one issue... the olives and joints had been soldered in place by the house builders! Smart? Why? He cuts the pump out and the pump is jammed of plastic bits and swarf. This is when his troubles really started, the joints on the 3 way valve started to leak - yep you've guessed it, soldered in at the olives as well! System drained as there is still debris in the pipes and corrosive water he beats a retreat to return shortly.

So, at the end of all that

What is the normal life for a CH pump?
What preventative maintenance should I have done myself?
How often should you flush systems out?


Happy New Year everyone

 

[gasglider]

1) A pump in a well designed, clean system can run for years. - I have removed pumps of 35 years old, that were still doing their job perfectly, however as an average, based on experience, 12 - 15 years would be a common life expectancy.

2) Unless you are a competent DIY'er, then there probably isn't much you can do in the way of maintenance. Pumps need to run with their motor shafts slightly above horizontal, a) to allow for initial and subsequent venting of air / gases, and b) for the rotor shaft to run in water (which acts as the lubricant) whilst putting mimnimum strain on the bearings and impeller. other problems with pumps are nearly always linked to bad system design and poor initial installation /cleaning / flushing of the system. You could check the concentration of Corrosion Inhibitor in the system water, as a general aid to the system as a whole.

3) As described above, a well designed system, that has been correctly dosed with inhibitor would never need flushing. However, the level of inhibitor will dilute over the years, and it is good practice to flush the system whenever any additional work, such as installation of new radiators is undertaken.

 

[JohnD]

the plastic bits and swarf ought to have been flushed out at commissioning, as should the cigarette ends, bits of brick dust etc that get into pipes during installation. there might be other bits lurking in the system too.

I suppose a mains flush or powerflush would have a fair chance of dislodging bits of rubbish. A powerflush costs hundreds of punds and will not be covered by your maintenance contract

A Magnaclean will trap the black sediment which forms when radiators corrode, and stop it accumulating in pipes, boiler or pump where it can eventually cause problems. On an old open vented system I think it is very useful. You can get other devices which trap circulating particles but AFAIK they are not generally found on domestic systems.

I am just a householder.

 

[wildebeest]

cheers for the replies.

I am presuming that the cost of a Powerflush (TM) , compared to just filling up the system as is with water/inhibitor may prevent similar problems in future if something else gets jammed in the pump is lower? I would rather prevent now and try to put things right that should have been done as standard 10 years ago when installed. That said - will a powerflush shift everything that's stuck in there?

When he comes back he is going to take the new pump off and flush with it bypassed - I have read that this is the norm anyway. In the T's and C's, apparently if I do not take up the flush when recommended previously and the system breaks, parts such as pumps will not be covered.

I really did feel for the BG guy as the system was falling apart in his hands and the call controllers had dumped 9 jobs on him in a 9-14:00 window.

 

[JohnD]

in your case, as there is known to be swarf and plastic fragments, I should think a powerflush will give the best results. You can expect it to get a lot of old sediment out too.

 

[petit_pablo]

In the T's and C's, apparently if I do not take up the flush when recommended previously and the system breaks, parts such as pumps will not be covered.

Unless he actually records it on the computer that he has recommended a flush i doubt you would get charged unless it goes again within a few months.

I really did feel for the BG guy as the system was falling apart in his hands and the call controllers had dumped 9 jobs on him in a 9-14:00 window.

Thats a normal day! The office doesnt grasp that we cant do that much work in half a day.

 

[petit_pablo]

Incidently, depending on where you live in the country, a powerflush will cost you £595 minimum, i always recommend a magnaclean with it for an extra £100

 

[JohnD]

but apart from the pain of paying for it, it would be an advantage to remove as much swarf and shavings as possible, the sooner the better.

 

[Nige F]

Name and Shame the original Builder .....wise move of yours getting a BG contract Don`t feel sorry they fitters earn c. £35k a year

 

[wildebeest]

BG came back today to redo the pipe work and found some more debris - an M6 bolt in the aerject thingy.

All seems to be OK now and it's certainly warmer than it has been over the past 2 weeks.

Just wondering how quickly the sound of air bubbles in the system (pipe work near boiler/airing cupboard) should finish? Could it be the pump is set too quickly?

 

[bengasman]

Sounds a proper powerflush is needed, incidentally, you don’t have to have that done by bg; they tend to charge twice the going rate.
A flush is not part of the maintenance, you either do it at the installation, or as remedial work when it was not done at the installation.
When you have a service contract, no need to do anything yourself apart from bleeding the rads if you have any suspicion on air in them.
You should not have to do it in your case, but on the better safe than sorry principal, you could put a bottle of inhibitor in every 3 years.