Valiant Eco tec 3 yr old install dilemma

[matz]

You need to put a bag or condom over the vent pipe to see if its pumping over.

Depth cold in F&E tank?

Distance between vent pipe and water cold?

Tony

will leave it off overnight and check in the morning...

 

[matz]

You need to put a bag or condom over the vent pipe to see if its pumping over.

Depth cold in F&E tank?

Distance between vent pipe and water cold?

Tony

depth of water in tank when cold 6"

distance between tip of vent pipe and water surface in the tank er its in the water by 1". The vent is a 22mm arm created in such a way that its actually sagging. When uprighted, the tip of the pipe is 2" above water. Its been in the water for some time as its corroded.

 

[simond]

The Vaillant 415 and 418 have a high flow resistance but can be used with microbore, you just have to size the pump correctly.

That in itself isn't the problem, it is the dirt, and why it is perpetuating.

 

[Agile]

depth of water in tank when cold 6"

distance between tip of vent pipe and water surface in the tank er its in the water by 1". The vent is a 22mm arm created in such a way that its actually sagging. When uprighted, the tip of the pipe is 2" above water. Its been in the water for some time as its corroded.

Ideally reduce the water level to 100 mm or 4". Bend ball valve arm to adjust the fill level.

Sounds to me that dipping vent pipe may have been the whole cause of your problem!

Immediately tie it up and still do the test with a bag as well.

Didn't you or anyone else ever question it?

Tony

 

[matz]

ok done all that! So what is happening when the vent pipe is under water that doesnt happen when its above?

Re. questioning it, its never registered with me to check it, I guess with hindsight I should have checked. As for anyone else, well the original installer was in the loft so I dont know why it wasnt noticed then....

thank you for your help

 

[Agile]

Because its under the water it forms a loop which has a low flow resistance and can easily cause circulation and when the tank water is circulated it brings in dissolved oxygen which rusts the radiators and blocks microbore pipes.

Was the tank water warm? That indicates circulation from the heating system.

Tanks should be cold !

Any heating engineer should always look at an F&E tank and identify issues like that and ensure they are rectified properly.

Of course there are a few cowboys who will see them and leave them to create a future series of remedial jobs!

Tony

 

[matz]

tank was warm yesterday but cold just now when I went up to tie the vent pipe back - CH had been on prior both times. Well I've done what you said plus tied a latex glove to vent so presume I need to see if water goes in there...

RE. the initial installers they are a local prominent independant company with maybe a dozen vans on the road - prices are keen as presume they need the work to keep their guys busy (keen not cheap!) I'm at a loss as to why they didnt mention the vent. I kind of think that with these volume type firms they are just in and out, job done and on to the next one rather than poking about trying to make sure an old system is working at its best...


well I will now watch how things go. If water comes out the vent, is it supposed to and if not whats causing that?!

 

[Agile]

Other problem is those firms have to employ who they can and often young and relatively inexperienced people. Or old ones who are just not so good.

Which is why a good self employed is often the best because he has to be quite good to make a living. Also they usually have a more helpful attitude to the customers rather than its just a job!

Tony

 

[Bunnyman]

Or u can have old inexperienced

 

[matz]

just as a matter of interest, I've just been up the loft after boiler been running for the first time for a few hours, rads very hot and the 15mm pipe that leads from the base of the expansion tank is warm and the 22mm pipe that vents into the tank is stone cold. Is the tank being heated up by water returning up the 15mm feed pipe?

sorry if I have the terminology wrong here!

 

[Agile]

As the system water expands then water will flow into the tank through the feed pipe.

So the feed pipe will be hot but the rate of expansion flow and the mass of water already in the tank usually means the tank water does not get any more than gently warm at the most.

Tony

 

[matz]

ah ok, seems thats normal then. I was assuming tank was getting warm due to vent pipe discharging but seems its the feed pipe. So if vent pipe not discharging, its not what they call pumping over?

 

[Agile]

Pumping over is the worst problem because as the water drops down from the vent it becomes very aerated.

That can cause rads to rust and pin hole at the rate of one a day!

Your immersed vent is slightly less bad but still very bad!

Now treat you water again and I have high hopes you may be back to as near normal as you can get with microbore!

Tony

 

[Steelmasons]

Because its under the water it forms a loop which has a low flow resistance and can easily cause circulation

Rubbish....

Please refrain from calling a "feed and expansion cistern" a TANK...

 

[Bunnyman]

An that's y our industry is thought of as full of Cowboys an chancers, because people who know Fook all make comments outside of their area of expertise!