hot water pumping over the f&e tank

[1sammyjones]

just fitted a new 3 port valve to a fully pumped system , customer had said that for years water had been pumping over the f&e tank , what would cause this ?? also radiators are getiing really hot although the controls are all off , after fault finding that i wired the 3 port in correctly , as stat wasnt turning off due to a wire in wrong terminal , sorted that out but the rads are still getting really hot even thou stat and programmer are both off ?? any suggestions please , go easy on me , im new to this game .. thanks 🙂

 

[doitmyself]

1. What's the water depth when the system is cold?
2. What's the vertical distance between water level and top of the vent pipe bend?
3. What's the vertical distance between water level and the pump?

 

[1sammyjones]

theres a good 50 mm plus.. between the vent and water level , depth of water is 20mm below overflow so i aasume it isnt a blocked feed overwise it would be overflowing correct ?? , and the distance from pump to tank is prob 2 meters

 

[lame plumber]

is the pump positioned correctly in regard to neutral point. I am assuming this is a gravity feed converted to fully pumped at some stage and done badly.

 

[1sammyjones]

yes although was thinking of changing the pump as sounding like it was running dry when on 3rd speed , the reason i went round the house first of all is because one radiator was getting hot while all controls off , now all radaitors are getting hot with controls off , , i changed the 3 port valve was a honeywell but changed it to a danfoss , i wired it in the same as the honeywell except the extra earth it has , also i exteneded the vent as well see if it would stop pumping over as well , but seems to be doing it again

 

[secret squirrel]

Was it pumping over before?

Why did you change the valve?

What has changed?

Are you sure the valve is in the correct way round?

 

[Ollieg]

B for bath on a 3 port.

Must be wired wrong if timer is off and things getting hot or failed cyl stat or prog.

Also if only 1 rad got hot b4 and now all get hot what's changed?

 

[1sammyjones]

i changed the valve coz one of the bedroom rads was getting hot so i thought maybe the 3 port was letting by , and yeah its the right way round , also as far as the wiring goes , i just wired them into the same as the old one , it had been pumping ober for ages the customer said , and when i looked at the vent it was scaled up alot as well , the heating system was quite dirty do you think this might have something to do with it ???

 

[doitmyself]

There's a good 50 mm plus.. between the vent and water level

The distance from water level to the opening in the vent is not really relevant (unless it's dipping in the water!). The important distance is from the water level to the top of the bend in the pipe. This should be at least 450mm.

depth of water is 20mm below overflow

Is that when the water is cold? If so, the level will rise when heated and some will escape via the overflow.
The cold water level should be about 50mm above the outlet at the bottom of the tank. This can be adjusted by bending the arm downward. Just make sure the valve opens before the water level reaches the outlet.

the distance from pump to tank is prob 2 meters

That's more than enough.

 

[GasmanxxxR1]

relitive position of cold feed and open vent, plus possibility of blockage in said pipe work can lead to pumping over, boiler still firing when theres no demand is probs a wiring issue

 

[Simon F]

one radiator was getting hot while all controls off , now all radaitors are getting hot with controls off

was the 1 rad HOT or warm? if it was just warm then probably a bit of reverse circulation taking place, where is the cylinder return piped in?
or 1 hot rad, (usually bathroom) piped into the hot water.
if the heating/ hot water is on with no call for it from programmer/thermostat then it has to be a faulty component or a wiring fault
pumping over, as asked before is the pump in the right position, after vent then feed
( vent, feed, pump)
also the pipe between vent and feed could well be filled with rubbish causing pumping over.

 

[Killy Bing]

Blockage between the feed and vent? Has it got an old air seperator on it? They tend to become block