Potterton suprima

[nickso]

Check that you have not got a blocked cold feed. It will be the pump overrun control which is keeping the pump running. Any suggestion that the pump and not the boiler is controlled by the end switches on two port valves is nonsense.

If it is an installation with two 2 port valves [known as an S Plan], there should be a bypass before the two valves so there is still circulation through the pump during overrun. It is commonly omitted.

It would not be nonsense if it was wired up without using the PL on the boiler, as already explained

but it's not so it is.

 

[Liverpool18X5]

right ok we was right it was the pcb keeping 240v on the pump all the while.

 

[onlyfitidealboilers]

dont know yet changing it on tuesday! am sure it is that tho

 

[matt1e]

Check that you have not got a blocked cold feed. It will be the pump overrun control which is keeping the pump running. Any suggestion that the pump and not the boiler is controlled by the end switches on two port valves is nonsense.

If it is an installation with two 2 port valves [known as an S Plan], there should be a bypass before the two valves so there is still circulation through the pump during overrun. It is commonly omitted.

It would not be nonsense if it was wired up without using the PL on the boiler, as already explained

also as already explained if it was wired without using the PL on the boiler then the boiler would also be firing

dont know yet changing it on tuesday! am sure it is that tho

providing the pump is wired back to the boiler pump terminals, It will be mate,

 

[spraggo]

providing the pump is wired back to the boiler pump terminals, It will be mate,[/quote]

With respect, you seem to have missed my point. The PL on the boiler is the pump terminal.

 

[picasso]

spraggo you have to make the distinction between permanent live and pump live, most modern boilers require a permanent live (240v) to run the display, pump overrun, fan overrun ect and then a switched live which can be anything between low volts dc to 240v ac, if the boiler doesnt require a permanent live then it doesnt have pump overrun.

 

[matt1e]

providing the pump is wired back to the boiler pump terminals, It will be mate,

With respect, you seem to have missed my point. The PL on the boiler is the pump terminal.

no I'm not mate, you're missing mine, as you missed seco's earlier

if the pump was switched via the internal switch in the motorised valve then the boiler would also be switched via this too ala s-plan
so if the pump was running all the time due to a stuck m/s then the boiler would also be firing too as seco services mentioned earlier
don't get me wrong I have seen gravity systems where there is a two port valve fitted on the CH side (to stop the upstairs rads getting hot on HW only) where the pump is switched via the valve so yes in certain situations you could be right but its unlikely in this case

If this perticular boiler has been wired correctly it has to have the pump wired back to its pump terminals with no exception
therefore if it is wired correctly the pump is controlled by the boiler
so if the pump is permanently running......................?

Matt

 

[Axel]

But can he get the new PCB out of the wrapper without evidence of breaking the seal on the packaging??!!

 

[spraggo]

Forgive me for banging on about this but I based my original reply regarding “pump running on,” based on an actual experience that I once had. However, it seems that I am not explaining this very clearly so I would like to give it one more try as follows:
The Boiler was connected from external live to its L N E terminals. The switched live was connected but the pump overrun or, pump live, was not connected.
The Pump was connected via the permanent live between the spur box and L on the programmer, continuing through the micro switches on the motorized valves and acted as the switched live to the pump and boiler by using the “S” plan. The pump overrun was bypassed.
It was found that the micro switch on the hot water MV was faulty by not opening when the MV closed. The boiler was retaining its own heat and only firing occasionally by the action of its own thermostat.

Cheers

spraggo

 

[powell30]

But surely this would cause overheat trips.

This is a solid lump of cast iron....where does the latent heat go if you wire as above???

 

[matt1e]

Forgive me for banging on about this but I based my original reply regarding “pump running on,”

before we go any futher

pump runs during the night every so often, blr doesn't fire tho.

if it was a m/valve issue the boiler would fire up as well.

providing the pump is wired back to the boiler pump terminals, It will be mate,

With respect, you seem to have missed my point. The PL on the boiler is the pump terminal.

no I'm not mate, you're missing mine, as you missed seco's earlier

if the pump was switched via the internal switch in the motorised valve then the boiler would also be switched via this too ala s-plan
so if the pump was running all the time due to a stuck m/s then the boiler would also be firing too as seco services mentioned earlier

based on an actual experience that I once had. However, it seems that I am not explaining this very clearly so I would like to give it one more try as follows:
The Boiler was connected from external live to its L N E terminals. The switched live was connected but the pump overrun or, pump live, was not connected.
The Pump was connected via the permanent live between the spur box and L on the programmer, continuing through the micro switches on the motorized valves and acted as the switched live to the pump and boiler by using the “S” plan. The pump overrun was bypassed.
It was found that the micro switch on the hot water MV was faulty by not opening when the MV closed. The boiler was retaining its own heat and only firing occasionally by the action of its own thermostat.

Cheers

(Please take note of the bold items in your quote then refer to the earlier quotes)
I don't doubt you at all that you came across a system wired like this many systems are wired different (rightly and wrongly) many boilers eg low water content ones don't req an over run facility
however

If this perticular boiler has been wired correctly it has to have the pump wired back to its pump terminals with no exception

with respect

Matt