Potterton suprima
- Thread starter onlyfitidealboilers
- Start date
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yo i dont think you understand how pump overrun works or how its wired because what you are saying does not make sense\!
Im always ready to learn even at 75, I understood that when the boiler fires up from cold the pump is fed from the switched live through the pump over run, and when the boiler begins to get hot the over run stat switches over so that the the pump is fed from the permanent live. This action reverses when the boiler cools down.
Am I on the ropes?.
sorry mate no! the pump is wired back to the boiler and is controled by the pcb & thermister keeps the pump running when the zone valves close.
like i said the boiler puts 240v on the pump not the external controls.
like i said the boiler puts 240v on the pump not the external controls.
If the boiler and pump are connected to the switched live through the mv, the switched live is getting its power from the permanent live
if its wired like this then you cannot have pump overrun as the mv will close opening the micro switch breaking the connection between permanent live and switched live.
This is unfair I`ve got two of you at me now. Wink, I did not say that the boiler was connected to the permanent live, only the pump.
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sorry mate no! the pump is wired back to the boiler and is controled by the pcb & thermister keeps the pump running when the zone valves close.
like i said the boiler puts 240v on the pump not the external controls.
Why don`t you listen, at no point have I said that the pump was controlled by the external controls.
I ain`t down yet.
errrr emm it kinda looks like you said the pump is controlled by the external controls here, I still think we should hit you with a brick anyway
errrr emm it kinda looks like you said the pump is controlled by the external controls here, I still think we should hit you with a brick anyway [/quote]
You are correct, but this is only for a brief period until the boiler gets hot and would make no difference other than delay the pump from starting for a brief period until the boiler gets warm, I understood that this was a bonus, why pump cold water through a hot cylinder?. Keep the brick handy you may deed it!!!!.
[/quote]You are correct, but this is only for a brief period until the boiler gets hot and would make no difference other than delay the pump from starting for a brief period until the boiler gets warm, I understood that this was a bonus, why pump cold water through a hot cylinder?. Keep the brick handy you may deed it!!!!.
errrr emm it kinda looks like you said the pump is controlled by the external controls here, I still think we should hit you with a brick anyway
You are correct, but this is only for a brief period until the boiler gets hot and would make no difference other than delay the pump from starting for a brief period until the boiler gets warm, I understood that this was a bonus, why pump cold water through a hot cylinder?. Keep the brick handy you may deed it!!!!.[/quote]
Correction, please read by first post again because I cannot see any where where I said the the pump was controlled by the external controls.
Anyway getting tired no so I`m of to bed. Hope to here from you in the morning.
ha ha
piccaso is correct; if the pump is connected through the MVs then the circuit would be broken when the MVs close. Unfortunately I was not able to reply to piccasso before I had a few ha ha`s etc. So I thought I would lie low hoping that someone else would enter the argument the sort of query as follows:ha ha
“What is the importance of the pump being connected to the permanent live or pump overrun stat on the boiler, as most boilers have a high limit stat?.”
To which I would have replied as follows:
“On boilers with cast iron or steel primary heat exchangers the overrun pump stat prevents the water temperature from rising beyond the boiler thermostat set temperature. Because when the boiler switches off by this thermostat, the heat in these heat exchangers, would still be transferring the heat contained within them into the water causing the boiler to kettle or even boil. Whereas the pump overrun stat will cause the pump to continue running after the boiler has shut down and will dissipate this heat into the system or heat store until the boiler cools down.” Now going back to my original reply to your query. I stated the fact that it was possible that the pump could continue to run if one of the MVs failed to close, assuming that it was, the “S” plan system. The reason that I stated this is surely I am not on my own in finding that I went to do a boiler change; you have had to run a separate permanent live to the pump overrun stat to connect to the new boiler because this was omitted on the old boiler. I have come across many instances where the original boiler had been installed with only a twin and earth supply to the boiler, being switched live, neutral and earth, making it impossible to connect to the permanent live. Also in some cases, where the earth was sleeved and used to connect to the permanent live, in the false belief that the boiler would be earthed through the cold water inlet.
This brings me to the question regarding pump overrun stats. Most manufacturers of low water content boilers, insist that you fit the overrun stat, but why? As these low water content primary heat exchangers would not be transferring a great deal of heat when the boiler shuts down. As well as the fact that the fan continues to run for a while and therefore speeds up the process of cooling the exchanger. I look forward to your replies with interest.
Cheers
spraggo
just to give my point of view
Spraggo your wrong, I'm siding with picasso your argument
and to the origonal post
then I'd say,probs nowt wrong with it
items 13 and 14 may have some relevence
From the installation instructions
Matt
Spraggo your wrong, I'm siding with picasso your argument
and to the origonal post
then I'd say,probs nowt wrong with it
items 13 and 14 may have some relevence
From the installation instructions
Matt
matt, sorry mate the pump is running on its own for hours! not mins!
M
mysteryman
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.
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
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