hw in f+e tank

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recently changed to a fully pumped system from gravity hw, but water seems to now be pumping straight in to the f+e tank in the loft, tried turning down the pump,no good, even does it cold, striaght from switch on.any ideas?the reason for the change is due to the old boiler(ideal concorde) died after 30 yrs, replaced with ferroli sigma, so connected the dhw heating pipes to the flow and return of the central heating circiut. everything is nice and hot, unfortunately this means the loft as well!
 
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where exactly is the pump on the pipework? It should be after the connection to the vent, not before.
 
sorry , the pump is on the return pipe of the ch system next to the boiler, this is located in the garage adjoining the house.
 
markd said:
recently changed to a fully pumped system from gravity hw, but water seems to now be pumping straight in to the f+e tank in the loft, tried turning down the pump,no good, even does it cold, striaght from switch on.any ideas?the reason for the change is due to the old boiler(ideal concorde) died after 30 yrs, replaced with ferroli sigma, so connected the dhw heating pipes to the flow and return of the central heating circiut. everything is nice and hot, unfortunately this means the loft as well!

You need to be more specific about your problem.

Is the water actually pumping into the tank (and therefore maybe overflowing?) or do you just mean it gets a bit warm?

Moreover, why is the pump on the return? This would mean that it is sucking water around the system. Also, if what you mean by "pumping into the tank" is that water comes out the vent, you have put the pump in the wrong place.

Also, have you installed the system yourself. If you have, you are a bodger and you should stay away from it in future.

Incidentally, use capital letters (e.g. for names) in your post - it makes overall reading easier - instead of just a lump of, what appears to be, a non-descript jumble of letters.
 
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Moreover, why is the pump on the return? This would mean that it is sucking water around the system. Also, if what you mean by "pumping into the tank" is that water comes out the vent, you have put the pump in the wrong place.

Many pumps are on the return side, and on some new installations. In general its not necessarily a definite cause of a problem.

Also, have you installed the system yourself. If you have, you are a bodger and you should stay away from it in future.

markd, take no notice of this it's one of sterose's stock joke lines. If you take offence the next line is to tell you have no sense of humour. :D :

Incidentally, use capital letters (e.g. for names) in your post - it makes overall reading easier - instead of just a lump of, what appears to be, a non-descript jumble of letters.

Surely not sterose, after all you made sense of it and even managed to give a reasonable piece of information in your first paragraph, (it just went downhill from then on). markd did have enough commas and a question mark which helped.

Are you having a bad day? There was a short period where your posts were becoming quite helpful, but you seem to have got back to the old vitriol, where reason gives way to verbal violence (or have I just missed the subtlety of another sterose wittisism mmm? :D: ).

Now, here is a non-descript jumble of letters:
kjsdhnughuryouhf jhfbcuyegfurohfmoidfsdhgfxbueyriurmcrpimkfkhdueie875tono4yc94497yb49797y97yt9cn7y9785yt97nf pirfcm094,9,9i,c-439mn9 y945yb 974yn 084nc97q3tyb 79q384yu0 8 u5087n0 8yu5tm0ump ut40 fu2. :LOL:
 
The pump was already on the return leg of the system (as are many), i saw no reason to change the location, perhaps you know different. I have since been advised that maybe raising the open vent pipe may solve the problem, so i tried it, it solved the problem when the system is running on heating and hot water but i still get a trickle from the vent when demanding hot water only. any more ideas please?
 
Raising the vent pipe will not help!!

Part the installation will have to replumbed so that it can operate as a fully pumped system

Gravity hot water installation does NOT have any pumps, valves or restriction between the boiler and the F&E cistern. Water flows from the boiler to the cylinder by natural movement

Now you have upset the system by making it fully pumped without altering the plumbing. Further more, with a pump in the safety loop (feed and vent) you have committed a plumbing sin.

Suggest you have vent and feed provided BEFORE the pump. Then the pump. After that two two-port valves or a three port mid-position valve.
 
DP wrote:
...with a pump in the safety loop (feed and vent) you have committed a plumbing sin.

Where did this come from DP? markd's pump is in the boiler return pipe as I read it.
 
My understanding is that the optimal position for the pump is after the vent and feed pipes on the flow pipe. Also the vent and feed pipes should not be further than 150mm apart on the main pipe.

This is copied from "Plumbing" by Treloar:

"The cistern must be placed in such a location that it will not be affected by the position and head of the circulating pump. A minimum dimension of the maximum head developed by the pump, divided by three needs to be maintained between the water level and the pump to prevent undue water movement in the f & E cistern."

So I guess that means if the maximum head made by the pump is 6 metres then there has to be a minimum 2 metre vertical distance between the cistern and pump.
 
Maybe I was taught wrong, but I have practiced not to instal any valves, fittings or other restrictions (like pump) in the feed or the vent pipe.

With the pump on the return, the flow is at positive pressure and the vent is connected to it. I would not be surprised if the pump is between the feed connection and the boiler. Above is speculation on my part- why else would there be pump over? Remember the three tee rule?
 
Maybe I was taught wrong, but I have practiced not to instal any valves, fittings or other restrictions (like pump) in the feed or the vent pipe.

Agree completely.

With the pump on the return, the flow is at positive pressure and the vent is connected to it.

You're right, I hadn't thought of it like this.

I would not be surprised if the pump is between the feed connection and the boiler. Above is speculation on my part- why else would there be pump over? Remember the three tee rule?

Bit like Christmas and New Year, they always fall in the same year, just the wrong ends. :D: The pump will always be between the feed and the boiler, but as you say, with the pump on the return, the vent will be at positive pressure (unless the boiler is bunged up).
 
John Reginald's book "Central Heating" states that pumping over (water coming out of the vent pipe) is usually caused by the cold feed and expansion pipe being connected to the return and with the circulating pump being between this connection and the boiler. Unless the vent pipe is high enough or the boiler creates a high resistance pumping over may occur".
 
oilman said:
Moreover, why is the pump on the return? This would mean that it is sucking water around the system. Also, if what you mean by "pumping into the tank" is that water comes out the vent, you have put the pump in the wrong place.

Many pumps are on the return side, and on some new installations. In general its not necessarily a definite cause of a problem.

Also, have you installed the system yourself. If you have, you are a bodger and you should stay away from it in future.

markd, take no notice of this it's one of sterose's stock joke lines. If you take offence the next line is to tell you have no sense of humour. :D :

Incidentally, use capital letters (e.g. for names) in your post - it makes overall reading easier - instead of just a lump of, what appears to be, a non-descript jumble of letters.

Surely not sterose, after all you made sense of it and even managed to give a reasonable piece of information in your first paragraph, (it just went downhill from then on). markd did have enough commas and a question mark which helped.

Are you having a bad day? There was a short period where your posts were becoming quite helpful, but you seem to have got back to the old vitriol, where reason gives way to verbal violence (or have I just missed the subtlety of another sterose wittisism mmm? :D: ).

Now, here is a non-descript jumble of letters:
kjsdhnughuryouhf jhfbcuyegfurohfmoidfsdhgfxbueyriurmcrpimkfkhdueie875tono4yc94497yb49797y97yt9cn7y9785yt97nf pirfcm094,9,9i,c-439mn9 y945yb 974yn 084nc97q3tyb 79q384yu0 8 u5087n0 8yu5tm0ump ut40 fu2. :LOL:

:D
 
Pumping over usually takes place when the feed is on the suction side of the pump (which is fitted on the return to the boiler). The pump sucks in water from the radiators as well as the F&E cistern. Soves this water into the boiler and out into the flow pipe. If the resistance on the flow is too great, water has to go someplace- it goes out of the vent pipe into the cistern, down the feed into the suction side of the pump. Couldn't be simpler. Move the feed to front of the pump, pump over stops because bothe feed and vent are now at positive pressure
 
Cheers DP that sounds about right, i'm not sure where the feed is connected, but if it is to the return pipe then it could be the problem. i'll call tommorrow and check! (not my house). P.S does moving the pump to the flow pipe have the same effect? only that would be easier to move. pps. what is the three tee rule?
 

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