hot water circulating pump "off-delay" relay switc

[steveuk1971]

what i basicaaly need is...... you know an extractor fan in a bathroom that when you turn the light on the fan comes on too automatically and stays on all the while the light is on but when you turn the light off then the fan keeps running for 60 seconds before turning itself off.

I am basically wanting to do the same but my light switch is my room thermostat and the fan is a circulating pump. If you see what I mean.

Is there an external "60 second off delay" control/switch or other device I can wire into the "switched-live" circuit to the pump?

Thanks.

 

[breezer]

what i basicaaly need is...... .

which is exactly what i posted a link to

 

[didthathurt]

The only one I could find that might do the job is the one Breezer suggested, here
http://www.tlc-direct.co.uk/Products/BGDT20.html
though, as he says, you may need to couple it to a relay to handle the load of a pump.

I think the pipe stat is the best idea - the problem is you need to keep water flowing until the internal temperature of the boiler has reduced sufficiently. If you connect it in parallel with the boiler's supply to the pump then either it or the room stat will command the pump to operate. Experiment until you find the temp at which the kettling stops and you should have what you need.

One word of caution, kettling in boilers is often due to excessive scaling within the heat exchanger and is solved by replacing the exchanger.

 

[steveuk1971]

what i basicaaly need is...... you know an extractor fan in a bathroom that when you turn the light on the fan comes on too automatically and stays on all the while the light is on but when you turn the light off then the fan keeps running for 60 seconds before turning itself off.

I am basically wanting to do the same but my light switch is my room thermostat and the fan is a circulating pump. If you see what I mean.

Is there an external "60 second off delay" control/switch or other device I can wire into the "switched-live" circuit to the pump?

Thanks.

Can anyone advise if this will work?? http://www.tlc-direct.co.uk/Products/EK320A.html

http://www.tlc-direct.co.uk/Technical/DataSheets/Elkay/EK320A.pdf

Thanks.

 

[gittish_bass]

Hey guy's hold up a minute, what make is the boiler?

steveuk1971 wrote:

I did have a pump-over-run circuit on the boiler itself, but this integral boiler switch/relay/overrun is broken and to save money on a whole new boiler PCB

pump over run can be thermostatic delay, not only timed electrically,
we may be talking pence not pounds

Regards

 

[steveuk1971]

Hey guy's hold up a minute, what make is the boiler?

steveuk1971 wrote:

I did have a pump-over-run circuit on the boiler itself, but this integral boiler switch/relay/overrun is broken and to save money on a whole new boiler PCB

pump over run can be thermostatic delay, not only timed electrically,
we may be talking pence not pounds

Regards

PCB would be for a Ferroli Sigma 40-60 boiler. Any idea?

 

[breezer]

Can anyone advise if this will work?? http://www.tlc-direct.co.uk/Products/EK320A.html[/QUOTE]

if you read the pdf you linked to you will see the answer to your question

 

[gittish_bass]

yep its PCB for the sigma, even if its on temp - unlikely, PCB activates pump. you could check wiring elec spec in installation inst.


http://www.ferrolicommercial.co.uk/Documents/Archive/Installation_Instructions/Sigma.zip

http://www.ashfordheating.com/images/uploaded/ferroli_boilers.pdf

 

[wportre]

I think every low water-content boiler has the same potential issue and I had the same (time-delay) idea for solving it. But the pipestat idea is a good one.

My boiler is a Keston 170, a very early condenser. I realise a lot of the more sophisticated functionality is now standard but the 170 is a simple heat/no heat device. So I immediately had to put a pipestat on to get a lower return temperature, with a relay to take out the pipestat and push the return temperature back up (to the boiler's internal thermostat level) when heating water. Adding another pipestat or even a time-delay on the pump adds more complexity, which already causes trouble for visiting technicians.

So, the question is, is there a simple control board that will replace the Honeywell connection panel and provide a little of the necessary logic? All I need is a couple of relays to control the pump and boiler but with more sophisitcated inputs than just valve switches so that the state of pipestats can be considered.

i.e. I originally had:

HW or CH valve open?
Yes=boiler and pump on

Which I turned into
HW or CH valve open?
Yes=pump on

HW valve open?
Yes=boiler on
No:
CH valve open?
Yes:
Return pipestat closed?
Yes=boiler on

And now I want it to become
HW or CH valve open?
Yes=pump on
No:
flow pipestat open?
Yes=pump on

HW valve open?
Yes=boiler on
No:
CH valve open?
Yes:
Return pipestat closed?
Yes=boiler on

Any ideas?
Thanks
WP