System overpumping into f & e tank.

[Ryan Jones]

From what you've described I'd say the piping layout is wrong. You say that the vent is after the HW motorized valve. So where does your system vent when you have heating only? I'd call a plumber quick whilst this is the least of your problems!

 

[Bunker]

Mods to move to Central Heating forum? 🙂

 

[quilkin]

Oops, I wasn't aware there was a separate forum, sorry. Probably better there if it can be moved.
Ryan, the vent (and the feed as well) are immediately before the pump, i.e after all the returns have joined via the boiler.
Alexmurchison, I turned everything off for 2 hours and then turned on hot water only. Pipes to & from hot tank, and return pipe through pump, all get hot quickly, as expected. Doesn't appear to be any blockage there. No filter or bypass, although there is a rad in the bathroom (next to hot tank)which is on the hot water circuit - but that heats up OK.
I just can't understand, if it's a blockage, why it would still be a problem with both heating & water activated, but not with just heating activated. Which section could the blockage be in? If the problem occured only with 'just hot water', or only with 'just heating', it would be obviously a blockage in the relevant section.

 

[alexmurchison]

hmmm, baffles me, just a thought but is the pump, "pumping" in the right direction ? not towards the feed and vent !

 

[Bryzer]

Any suggestions, or will the pipework have to be re-routed in order to overcome this issue?

 

[quilkin]

Ah! Just found a site which says this: 'The resulting rust will end up causing a blockage, usually at the point where the cold feed enters back into the system' - so I just tested, and yes, just at that point, between the feed & expansion connections (only 2 inches!) the magnet is attracted - nowhere else!
Too late now to drain down and remove pump, but tomorrow I will do so, I should be able to dig out any blockage there, it's so close to the pump. Watch this space....

 

[Whyme]

glad you found it but we said blockage from the off.. the magnets attracted to hardened black sludge not rust. thats how magna cleans work they attract magnatite sludge and trap it. Thats also why pumps fail on sludgy systems because they create a magnetic field and it sticks and hardens...Think you should thank everybody who screamed blockage pal :smile:

 

[peteheat]

And another plumber loses a days pay........................

 

[thompsonbrown]

if your draining down to remove blockage. I would also change position of the vent & cold feed pipe work. install a air vent b4 the cylinder and replace that ball-a-fix for a gate valve.

 

[Bunker]

..and the water in the system has the inhibitor replaced at least annually

I know you said you'd put some chemical cleaner in, Id do that again then after flushing out add plenty of good quality inhibitor as whatever you have been putting in, has been failing you.

 

[diamondgas]

if your draining down to remove blockage. I would also change position of the vent & cold feed pipe work. install a air vent b4 the cylinder and replace that ball-a-fix for a gate valve.

You'd fit a valve on an expansion pipe? Scary!! Don't EVER do that quilkin!!

quilkin and Bryzer ... You'd benefit from having someone check out the pipework configuration pump speed and bi-pass settings on both your systems. Systems shouldn't pump over unless there's an issue with the layout... IMHO 🙂

 

[quilkin]

Thanks everyone for all help & suggestions. Overpumping into the header stopped now, there was rust (red rust, not black sludge) in the return pipe to the pump, just betwen the f & e pipe connections. Nowhere else, pump itself was clean; there was a bit of rust in the 3-way valve so it was sticking a bit (I cleared that before starting this thread) but not enough to block it. Also no sludge or rust visible in the manifold connections to the microbore parts.
Yes I'll put some more inhibitor in after cleaning again, I think the original problem was the expansion pipe dripping onto the tank overflow so over time the inhibitor all disappeared. Either that or my plumber didn't add any when the boiler & tank were replaced 3 years ago.

 

[Whyme]

Rust, dont see that much. Glad too hear its all sorted for ya.:yes:

 

[Bunker]

i had the same a few weeks ago, stuff was red but was built up from the rubbish at the bottom if the f&e tank.

 

[diamondgas]

i had the same a few weeks ago, stuff was red but was built up from the rubbish at the bottom if the f&e tank.

I hope you didn't leave that valve on!!!

 

[Bunker]

I hope you didn't leave that valve on!!!

Nah, I turned it off lol!!

(no, replaced it with comp union)

 

[quilkin]

Did someone leave a dead body in that tank?:tongue3: Seriouosly though my red stuff was packed hard, rusty-red not blood-red.

 

[peteheat]

Good photos Bunker.

Many consumers believe that cleaning the F + E tank tank and removing the blockage is the answer to their problems, it is on a temporary basis.

They are but symptoms of what is happening in the heating system, symptoms that if addressed properly can mean the difference between a short time to a replacement heating system and getting another ten years without major expenditure.

 

[diamondgas]

:iagree: It's fixing the symptoms but not the cause 🙂 :iagree:

 

[Bryzer]

Thanks for all the input. Problem now resolved. The oftec registered heating engineer who installed the recent boiler (about 3 years) never took out the hot water cylinder thermostat from the old gravity feed system. Quite alarmed really. Installing a pumped system with a blockage in the pipework leaves me feeling let down by one of your peers.:disappointed: