steaming water in F&E tank

[schuey1972]

Hi, I have a problem, the only way I can get my heating to stay on (bolier not to trip out) is to remove water from my F&E tank which is steaming hot!!!!! and is constantly overpumping, the only way I can stop this pumping is to disable the pump completley (remove a wire - not great but only way), which obviously means I have no heating at all although hot water seem to operate pefectly OK on a gravity feed alone???? (am I OK leaving the hot water to operate in this way?), I have been told that this extra water which never seem to reach the overflow outlet can only be coming from a split coil within the hot water cylinder, is there any way of 100% condeming the cylinder ? Also with just hot water either with or without the pump running the boiler casing remains at a normal luke warm feel, however when heating is running (after water removal from F&E tank) the bolier casing gets very hot but all rads heat up with no probs. Some extra info that may or maynot be of use, I had the pump and 3 way valve both replaced in Feb 2011 (both were very soiled up) and also removed all downstairs rads in the spring (all between 3-8 years old but had cold bottom centres again due to soiling), flushed through, refitted, drained system, added inhibitor, refilled system and bled all rads the heating and hot water were all working fine after this. I have tried a magnet on all pipes in and around tanks/pump/valve etc and all are non magnetic. F&E tank is on the same framework as the cold tank which are both just above the hot cylinder. Sorry it's a long 1st post but I am getting deseperate now the weather is taking a change. Look forward to any help/suggestions.

 

[JAK99]

Hi.If the problem is a split coil within the HWC, then you will get dirty water coming out of the hot water tap, because the CH water is mixing with the indirect ("normal water") water within the HWC. So the water coming out of a hot water tap will be contaminated with inhibitor etc from within the CH system. If the hot water coming out is uncontaminated, then the coil inside the HWC is not split. So now you can confirm or eliminate at least this possibility. jak99

 

[schuey1972]

Hi jak99, thanks for response, the hot water from the taps is perfectley clean. Could this be due to the components in the 10 way board being incorrectly wired since new pump and valve fitted?? As looking at wiring diagrams compared to what I have fitted (Y-Plan) I only have 5 wires coming in (tank stat, pump, 3 port valve, controls and 1 other either from boiler or main electrical feed??????) I have no room stat anywhere in the house although I am looking at installing a wireless one for ease, are these easy to install or can it be wired without?? My father is a part-p qualified electrician so would be doing any wiring changes and we are thinking of starting again to eliminte the wiring as all does not seem to match as it should but we cannot understand why this would cause the overrun of this steaming water.

 

[Js58gas]

It's sounds like you have a restriction somewhere in the system . I noticed you said you tried putting a magnet on the pipework to pin point magnetite, I had a job last week where I did the same thing looking for a restriction around the cold feed area but did not stick. I had to cut the pipe to put in a gate valve and what I found was the 22mm pipe was restricted down to about 8mm and I cut out about 3m of pipe from there. So this shows just because the magnet does not stick it does not always mean there is no restriction. Also is the water in the f and e tank dirty if it is I would cut the CF/OV area just to make sure there is no non magnetic sludge in the pipework. I hope this helps

 

[JAK99]

Hi. Sorry, I don't know much about electrical wiring, so cannot help in that respect. Are you absolutely sure that the hot water is being pumped out to the feed & expansion tank, ie the one that serves the boiler? If so, it could mean that the boiler thermostat has failed: the boiler carries on heating the water, when it shouldn't; and the only way for the hot water to go is up into the F&E tank. I would test the boiler thermostat. Not sure how, though, since I am not an electrician.Jak99

 

[JAK99]

Any luck? JAK99

 

[PowerFlushAssoc]

Very likely: Because of the obvious presence of sludge and the pump burning out, it is likely, that the "H" (down feed pipe and vent pipe) branch has a hardened sludge build-up / block. You should be able to find it by following the return pipe from the pump back until you reach a section where two pipes branch straight up, to the F&E tank. You will need to cut out and clean / replace this section. If you don’t remove the sludge in the rest of the system, by power flushing, the hardened block / restriction will just build back over time. Draining the system down in not enough if you are already experiencing problems from sludge.


Test: see if a magnet sticks to this section. Copper pipes are non-magnetic so if it sticks, it is attracted to the sludge build-up inside the pipe. Another way of testing (not as accurate) is slowing the pump down from 3 to 1. If it stops over pumping; it’s a build-up / restriction not a block which should be in this section.

 

[WHPES]

Easy way to check if the coil in your cylinder is split - before you go to bed, turn off your mains water and hot water / heating ang boiler, Before anyone draws water in the morning, look at your tanks and see if the water in both has gone to the same level (assuming they weren't the same level to begin with)

Heavy corrosion in the system and blockages are usually an indication of fresh water getting in and causing corrosion, often through a split coil.

 

[schuey1972]

Hi, tried the magnet test - no luck there, pump is only set to no 1 already but strangley enough the last 2 evenings the haeating has come on and stayed on no probs without even having to remove any water from F+E tank ??????? I have done nothing except give the boiler a few hard bangs on Weds eve when nothing I seemed to do stopped it from tripping out after that it was fine and hes been since although it does still get very warm to touch the casing ????? could it be anything in the boiler ???? looks like I am going to have to call out a professional soon, thanks for all the suggestion though, a real head scratcher.

 

[jase158]

just answered your own question, you gave boiler a whack which obviously sorted problem out, temporarily, so need to get a pro in to have a look.

 

[diamondgas]

schuey1972 .. Hi and welcome to the forum

At no time should you have a constant flow of water coming out of your open vent pipe or steaming hot water in the header tank .... Depending on how long this has been going on tends to decide whether you rip it all out or try and repair, to be honest!!

How old are we talking regards 'y'plan install?

Personally you need to address the pumping over now to stop any further damage!

 

[schuey1972]

Hi, boiler and all tanks approx 15 years old, pump and 3 way valve less than 1 year old, but today, again boiler kept tripping out until I gave the thermostat knob a twist back and forth a few times and then been on fine since then all be it a very warm-hot boiler case to touch, but still overpumping in F+E tank, could it be there is more than 1 problem, I think so.

 

[jase158]

I'm not a gas engineer but sounds like a heat problem. get an engineer in asap, they will know what they are doing.

 

[schuey1972]

All sorted, boiler serviced inc new stat and presurised heating system fitted